SIGMA 2023

ASTROSOC 39 Figure 2. Astronaut Serena Auñón-Chancellor harvests red Russian kale and dragoon lettuce from Veggie on Nov. 28, 2018. Credits: ESA/Alexander Gerst Figure 3. The first growth test of crops in the Advanced Plant Habitat aboard the International Space Station yielded great results. Credits: NASA

ASTROSOC 40 Lahiru Gamage Level Three Undergraduate Faculty of Indigenous Medicine References Image Courtesy • Wheeler, R. M. (2017). Agriculture for Space: people and places paving the way. Open Agriculture, 2(1), 14–32. https://doi.org/10.1515/opag-2017-0002 • Space, G. P. I. (n.d.). Growing plants in space. NASA. https://www.nasa.gov/content/growing-plants-inspace • Habitat, P. (n.d.). Plant Habitat-04. NASA. https:// www.nasa.gov/content/plant-habitat-04 • Monje, O., Stutte, G. W., Goins, G. D., Porterfield, D. M., & Bingham, G. E. (2003). Farming in space: Environmental and biophysical concerns. Advances in Space Research, 31(1), 151–167. https://doi. org/10.1016/s0273-1177(02)00751-2 • Sempsrott, D. (2021). BRIC-24: An experiment frozen in time and space. NASA. https://www.nasa.gov/feature/bric-24-an-experiment-frozen-in-time-andspace • Figure 1 - Heiney, A. A. (2017, April 6). Space Agriculture planted in History – Kennedy Space Center. https://blogs.nasa.gov/kennedy/2017/04/06/ space-agriculture-planted-in-history/ • Figure 2,3 - Space, G. P. I. (n.d.). Growing plants in space. NASA. https://www.nasa.gov/content/growing-plants-in-space Biological Research in Canisters (BRIC) It is a petri-dish fixation unit (PDFU) flight hardware introduced to study microbial organisms including plants, mosses, algae, and cyanobacteria growth and other related factors in microgravity. It was very useful in studying the changing patterns of genes in space, plant stresses related to microgravity, and the defense mechanisms of plants in space etc. Thus, this experiment opened up to the development of new methods in space farming. In conclusion, space farming is an emerging science that is growing rapidly and despite its numerous challenges, it has gained interest all over the world. It is very valuable not only in improving space technology and in that it will benefit future generations on space expeditions but also in improving Agriculture on Earth.

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ASTROSOC 42 ek; G+kpf;F mg;ghy; fhzg;gLk; re;jpud; njhlf;fk; gy xspahz;L njhiy tpy; cs;s Nfyf;]pfs; tiuMuha;tjw;fhf kdpjdhy; gy jrhg;jfhyq;fshf mjp njhopDl;gk; tha;e;j njhiyfhl;bfs; tpz;ntspf;F Vtg;gl;l tz;zNk cs;sd. ,e;j tupirapy; `gpy; njhiyfhl;bapd; mLj;j gupzhkkhf fUjg;gLk; N[k;]; ntg; tpz;ntsp njhiyfhl;bahdJ Kf;fpa ,lj;ij tfpf;fpd;wJ. Muk;gj;jpy; ,j; njhiyfhl;bf;F 'mLj;j jiyKiwapd; tpz;ntsp njhiyfhl;b' vd;W ngauplg;gl;lJ. vdpDk; N[k;]; E. ntg; vd;gtupd; epidthf 2002k; Mz;L nrg;nlk;gu; khjk; N[k;]; ntg; vd;W ngau; khw;wg;gl;lJ. N[k;]; ntgpdJ gzpfspy; ehrh cld; ,ize;J INuhg;gpa epWtdk; ESA kw;Wk; fNdba epWtdk; CSA ck; ,ize;J nray;gLf;fpd;wd. ,jd;gb 1996k; Mz;L ,j;njhiyfhl;b njhlu;ghd jpl;lk; Kd;nkhopag;gl;lJ. gpd; Rkhu; 25 tUlfhy Ma;tpd; gpd; 2021k; Mz;L brk;gu; 25k; jpfjp fhiy 7.20 kzpastpy; gpuQ;R fahdhtpy; ,Ue;J Mupahd; 5 VTfyd; %yk; Vtg;gl;lJ. mjid njhlu;e;J 2022k; Mz;L [dtup khjk; R+upa-G+kp L2 yq;nuQ; Gs;spia mile;J mjd; gzpfis Muk;gpj;jJ. ,jd; Kjy; fl;lkhf 2022k; Mz;L [{iy 11k; jpfjp ntg; njhiyfhl;b %yk; vLf;fg;gl;l SMACS -0723 vd;w Nfyf;]p $l;lq;fspd; gbkk; kf;fs; ghu;itf;F ntspaplg;gl;lJ. ,jid njhlu;e;jJ ,jw;F Kd; `gpy; njhiyfhl;b %yk; vLf;fg;gl;l fupdh neGyh(crania nebula)> WASP-96b> ];Bgd; Fapd;]; (Stephan quiets)> njw;F tisa neGyh (southern ring nebula) Mfpa gbkq;fs; ntg; njhiyfhl;b %yk; kPz;Lk; vLf;fg;gl;L mjd; czu;- jpwid ntspgLj;Jk; tifapy; kf;fs; kj;jpapy; ntspaplg;gl;lJ.

ASTROSOC 43 Vd; N[k;]; ntg; thdpay; njhiyfhl;b? N[k;];ntgpd; rpwg;gk;rk; vd;dntd;why ; ,J mfrptg;G kpd;fhe;jiyia mbg;gilahf nfhz;L nraw;gLk; xU tpz;ntsp njhiyfhl;bahFk;. kw;Wk; ,jd; Kjd;ik fz;zhb 6.5kPl;lu; tpl;lk; nfhz;l 18 mWNfhztbt gFjpfshy; MdJ. ,jdhy; ,J cau; czu;jpwd; kw;Wk; cau; njspTjpwd; kpf;fjhfTk; fhzg;gLfpwJ. MfNt `gpy; njhiyfhl;bapdhYk; ghu;f;f Kbahj my;yJ gjpT nra;a Kbahj tpz;ntngUntbg;gpd; gpd; ,g; gpugQ;rk; ,Uz;l gpuNjrkhf fhzg;gl;lJ. mf;fhyj;jpy; el;rj;jpuq;fNsh Nfyf;]pfNsh Njhd;- wpapUf;ftpy;iy khwhf mZJzpf;iffshd GNuhj;ud;> epA+j;jpud; kw;Wk; ,yj;- jpud;fNs fhzg;gl;ld. gpd; gpugQ;rk; Fspu;r;rpaila mZJzpf;iffSf;- fpilNa madhf;fk; ,lk;ngw;wd. ,jd; tpisthf Ijurd;> Jj;Njupak; Nghd;w mZf;fspd; Njhw;wKk; mjd; kPs; madhf;fKk; ,lk;ngWk;. ,t;thwhd kPs; madhf;fy; fhyfl;lj;jpy; ,g; gpugQ;rk; xspGftplh jd;ikia nfhz;bUe;jJ. ,e;epiyikfspy; fl;Gy xspaiy %yk; mtjhdpg;gJ njsptw;wjhFk;. MfNt ,t;thwhd re;- ju;g;gq;fspNyNa cau; njspTjpwd; kpf;f mfr; rptg;G epwkhiy Njitg;gLfpd;wJ. vdNt kPs; madhf;fy; fhyfl;lj;ij gw;wp mwpe;J mJ njhlu;ghd Ma;tpw;F ntg;njhiyfhl;bapd; gq;fspg;G mtrpak; MFk;. 1. ,Uz;l Afj;jpd; KbTk; Kjy; xsp kw;Wk; kPs; madhf;fk; glk; 1:`gpy; kw;Wk; N[k;];ntg; %yk; vLf;fg;gl;l Fuq;F jiy neGyh sp $Wfis ntg; njhiyfhl;b %yk; mtjhdpf;f$bajhf ,Uf;Fk;. ,jd; fhuzkhfNt ,j; njhiyfhl;b ,e;e Afj;jpd; mjp etPd njhiyfhl;bahf miof;fg;gLfpwJ.ntg;njhiyfhl;bapdJ kpf Kf;fpa Nehf;fk; gpugQ;rj;jpd; xt;nthU fl;lq;fisAk; Muha;e;J mjd; tuyhw;iw mwptjhFk;. ngUntbg;gpd; gpd; Njhd;wpaKjy; xsp njhlf;fk; Nfyf;]pfs;> el;rj;- jpuk; kw;Wk; fpufq;fspd; gupzhk tsu;r;rp tiu mwpe;J nfhs;tjhFk;. ,jdbg;gilapy; N[k;]; ntg; njhiyfhl;bapd; gpugQ;rk; Fwpj;j Njly;fis gpd;tUk; ehd;F tiff;Fs; mlf;fyhk;.

ASTROSOC 44 2. Nfyf;]pfspd; Njhw;wk; Nfyf;]pfs; gw;wp tpQ;QhdpfspilNa ,d;wstpYk; gy Nfs;tpfs; fhzg;gLfpd;wd. Nfyf;]pfspd;Njhw;wk;> mtw;wpd; tbtk; kw;Wk; Nfyf;]pfSf;Fk; fUe;JisfSf;Fk; ,ilNa cs;s njhlu;G vd gy jug;gl;l Nfs;tpfs; fhzg;gLfpd;wd. N[k;]; ntg; njhiyfhl;bahdJ fhyk; gpd;Nehf;fpa epiyapy; cs;s tpz;ntsp $Wfis mtjhdpg;gjhy;> ntg; njhiyfhl;b %yk; fpilf;Fk; ,we;jfhy Nfyf;]pfspd; fl;likg;GfisAk; jw;NghJs;s epfo;fhy Nfyf;]pfspd; fl;likg;GfisAk; xg;gpLtjd; %yk; Nkw;$wpa Nfs;tpfSf;fhd jPu;Tfis ngwyhk; vd tpQ;Qhdpfs; ek;Gfpd;wdu;. glk; 2: ntg; njhiyfhl;bapdhy; ngUntbg;gpd; gpd; Njhd;wpa xspUg; nghUl;fis mtjhdpj;jy; el;rj;jpuj;jpd; mbg;gil fl;likg;G mZthFk;. el;rj;jpu $l;lq;fs; Nru;e;J Nfyf;]pfs; cUthFk;>mNjNtis Nfhs;fs; el;rj;jpuq;fis ikakhf nfhz;L ,aq;Fk;. nghJthf el;rj;jpuq;fspd; gpwg;gplk; neGyh MFk;. mjhtJ neGyh vd;gJ thA kw;Wk; J} R glyk; epuk;gpa $l;lkhFk;. `gpy; njhiyfhl;b %yk; ,jid mtjhdpg;gJ N[k;]; ntg; njhiyfhl;bapDld; xg;gpLk; NghJ kpfTk; njsptw;wjhFk;. Vndd;why; el;rj;jpuq;fs; ntspapLk; xspahdJ thA kw;Wk; J}Rfshy; xspGftplhJ jLf;fg;gLfpwJ. Mdhy; N[k;]; ntg; njhiyfhl;bapd; mfrptg;G kpd;- fhe;jiyfis fhuzkhf kpf njspthf mtjhdpf;f KbAk;. 3. el;rj;jpuq;fs; kw;Wk; Nfhs;fspd; gpwg;G

ASTROSOC 45 kdpjd; tpz;ntspia gw;wp Muha njhlq;fpa fhyk; Kjy; ,d;W tiu gy Ntw;Wfpufq;fs; fz;Lgpbf;fg;gl;Ls;sd. N[k;]; ntg; njhiyfhl;bapd; kpf Kf;- fpa gad;ghLfspy; xd;W Ntw;Wfpufq;fspd; tspkz;lyq;fs; gw;wp Muha;tjhFk;. ,jpy; cs;s nfhuhdhfpuhg; njhopEl;gk; %yk; Ntw;Wfpufk; cs;s ,lj;ij fw;gid nra;ayhk;> ,jd; %yk; mjd; mikT> Nfhil> Fspu; Nghd;w thdpiy khw;wq;fis fw;fyhk;. MfNt G+kpia xj;j tspkz;lyj;ij nfhz;l fpufq;fis fz;lwpa ,J toptFf;Fk;. ntg; njhiyfhl;bapy; cs;s czu;jpwd; kpf;f fUtpfshy; vLf;fg;gLk; glq;fspd; %yk; ngwg;gLk; epwkhiyia mstpLtjdhy; mf;fpufq;fspd; taJ kw;Wk; jpzpTfsAk; mstpl KbAk;. kw;iwa fpufq;fs; kw;Wk; Nfyf;- ]pfs; kl;Lkd;wp ekJ #upaFLk;gj;ij gw;wpAk; Mokhf fw;gJ kpf Kf;fpakhdjhf tpQ;Qhdpfs; fUJfpd;wdu;. mjw;F jw;NghJ N[k;]; ntg; JizGupfpwJ. Kd;Ng $wpaJ Nghy; ,j; njhiyfhl;bapd; %yk; Nfhs;fspd; tspkz;lyq;fis kpf Jy;ypakhf Muhayhk;. mjdbg;gilapy; nryt;tha; fpufjpd; Nkw;gug;G kw;Wk; tspkz;ly $Wfs; njhlu;ghf Muhag;gLfpReferences 4.Ntw;Wfpufq;fSk; capupdq;fSk; ● About Webb/NASA. (n.d.). https://jwst. nasa.gov/content/about/index.html ● Early Universe - Webb/NASA. (n.d.). https://jwst.nasa.gov/content/science/firstLight.html ● Galaxies Over Time - NASA JWST. (n.d.). https://jwst.nasa.gov/content/science/galaxies. html ● Telescope, N. J. W. S. (n.d.). Webb Rules Out Thick Carbon Dioxide Atmosphere for Rocky Exoplanet (Spectrum). Flickr. https://www.flickr. com/photos/nasawebbtelescope/52988301957/ in/album-72177720305127361/ ● Star Lifecycle - Webb/NASA. (n.d.). https://jwst.nasa.gov/content/science/birth. html ● Other Worlds - Webb/NASA. (n.d.). https:// jwst.nasa.gov/content/science/origins.html ● Optical Telescope Element: James Webb Space Telescope. (n.d.). https://jwst.nasa.gov/ content/observatory/ote/index.html glk; 3: el;rj;jpuq;fspd; gpwg;G njhlu;ghf ntg;njhiyfhl;bapdhy; mtjhdpf;fg;gl;l fOF neGyhtpy; gilg;G J}z;fs; glk; 4: ntg;gpdhy; mtjhdpf;fg;gl;l TRAPPIST-1-C Nfhdps; epwkhiyAk; mjd; %yk; Muhag;gl;l mf;Nfhspd; tspkz;lyKk; wJ. NkYk; #upa FLk;gj;jpy; cs;s tpz;fw;fs;>thy;el;rj;jpuq;fspd; epwkhiyfis mtjhdpg;gjd; %yk; mtw;wpYs;s fdpkq;fs; njhlu;ghd fw;ifnewpf;F cjTk; . ,J G+kpapy; vjpu;fhyj;jpy; Vw;gLk; fdpkq;fspd; jl;Lghl;b jPu;thf mikAk;. Level One Undergraduate tpQ;Qhd gPlk;

ASTROSOC 46 ASTROSOC A Dip into the Fabric of Space-Time: A Brief Summary of Cosmological Concepts 46

ASTROSOC 47 Scientific inquiry is a beautiful thought-organism birthed to explain natural observations, backed by experimental models. This thought process has brought about changes to how we perceive natural phenomena from one form to another through millennia. “Cosmology”, a prominent field tying together both theoretical and applied sciences, is a such changing area of study. Primarily focused on describing the large-scale nature of the universe, “cosmology” can be loosely defined as the physical study of the universe as a whole, including its composition and chronology in the form of evolutionary dynamics. The idea that the universe possesses evolutionary dynamics was rather foreign and fantastical at first; many great minds themselves believed it to be static throughout time. However, mathematical considerations gave way to predictions that not only accounted for a static model of the universe, but also models where it continuously expands, and expands to a limit followed by contraction as well. While many representations of the universe have come to light throughout the ages, we can consider Albert Einstein’s theory of general relativity to be our main point of reference in this discourse. Within this theory, Einstein outlined the relationship between the geometries of space-time with the mass-energy-momentum distribution of space-time. This is given by the Einstein Field Equation (EFE) as follows1 . The FLRW Metric: Mapping the Geometries of the Universe To start off, the geometry of the universe is built up by considering the assumptions given under the Cosmological Principle. The Cosmological Principle: Fundamentally required for the mathematical description of a dynamic universe, this principle considers that, at a large scale, the universe is isotropic and homogenous. And thus giving an isotropic and homogenous geometry to the universe as well. Following this, we can consider three simple geometric models for the universe; a close-ended or spherical shape, a flat shape, or an open-ended or hyperbolic shape. The mathematical characteristics of these three geometries can be represented separately through metric tensors, most often represented collectively through the Friedmann-Lemaitre-Robertson-Walker (FLRW) Metric. These are given as follows. 1 The terms represented through this equation as well as their significances will be of focus throughout this article.

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ASTROSOC 49 As the FLRW metric is a diagonal metric its inverse is simply the metric containing the inverse of all the elements of the FLRW metric. For a diagonal metric we can obtain the connection coefficients as follows The set of expressions obtained from the above are necessary to calculate the Ricci tensors, which are related to the connection coefficients as mentioned below. While this seems to be a rather long computation, very few coefficients are in fact non-zero in value, and most of those that are non-zero are in fact equal to quite a few others, making the simplification easier. However, care must be taken at each step as the indices can be easily confused. Following the computation of the Ricci tensors, the Ricci scalar can be obtained as follows. 2 It should be noted that the notations μ, ν, σ, α, β are merely indices. They can be represented to take the quantities ct, r, θ, and ϕ as accordingly

ASTROSOC 50 Evidence on an Expanding Universe: Cosmological Red-Shift The FLRW metric provided a rather striking insight into the evolutionary dynamics of the universe. Let’s consider a geodesic; or a path that a free particle takes in space-time, unaffected by any nongravitational force. It can be seen that a space-time pathway where the spatial coordinates remain constant and only the time coordinate changes, satisfies the conditions needed to make it a geodesic4. This is a direct implication to show that the spatial coordinate grid defined by the FLRW metric changes (expands or contracts) along with the changes in the universe. This can be rephrased as the grid of space itself being expanded (or contracted) similar to any change the universe itself shows, thus changing the distance between any two points in the fabric of space-time as time progresses. The importance of introducing the scaling factor ɑ(t)is recognized here, as the grid expands according to this factor in the three different geometries. Furthermore, the time derivative of the scaling factor shows the rate at which the universe is expanding, and the second time derivative shows the acceleration at which the universe expands. While the theoretical implications of this was largely thought of to be false (even by Einstein, who at the time proposed a static model of the universe), the work of Vesto Slipher, Georges Lemaitre and Sir Edwin Hubble soon gave experimental evidence to an expanding universe. Observations that the spectra of galaxies showed larger redshifts as the distances to these galaxies from Earth increased, gave rise to the thought that the galaxies themselves were moving away from Earth. Lemaitre proposed the theory that these were in fact moving as the universe itself was expanding, proceeding on to calculate a constant that gave a linear relationship between the observed redshift of a galaxy and the distance to it from Earth. This was independently derived by Hubble as well, and is now coined as the Hubble-Lemaitre Law. Lemaitre parameterized the observed redshift (z=Δλ/λ) using the scaling factor as dependent on time) as The prominence in redshifts observed by distant galaxies cemented the concept that out universe was indeed, expanding. Friedmann Equations: Elegant Solutions, Groundbreaking Implications Published in 1924, Alexander Friedmann presented two equations that provided solutions to Einstein’s Field Equation in the form of the rate and acceleration of the expansion of the universe. By considering the as a perfect fluid universe at large scales the stress-energy tensor can be represented by The derivations mentioned previously would give . This was related to the expansion of the universe by the Hubble constant (which is

ASTROSOC 51 These two equations tell us about the expansion rate (å), and the expansion acceleration (ä) of the universe respectively, and their relationship to the geometric curvature (k), mass-energy density (ρ), pressure (p), and the cosmological constant (Λ). The latter four parameters are those that can be experimentally obtained, and thus highlights the importance of research into the field of cosmology, as determining these parameters give the nature of the space-time fabric itself! To rephrase this, these equations provide insights into a variety of models of the universe that are determined by the four parameters themselves. Einstein’s Static Universe Let’s take a look at the flexibility of the Friedmann equations by considering a static universe first. Here we have no expansion (å = 0) and thus no acceleration of expansion (ä= 0) of the universe.Einstein assumed that the pressure was also zero here. This gives us the following from the Friedmann equations. Since the mass-energy density has to be positive, we can take that both Λ > 0 and k > 0 here. However, as we saw earlier, k = {−1, 0, +1} only, thus the solution gives that k = +1. This implies that the static universe is geometrically a sphere, and that the cosmological constant varies according to the inverse square law. This theory however was disproved by the experimental evidence of cosmological redshifts in galaxies.

ASTROSOC 52 De Sitter’s Empty Universe Here, de Sitter assumed that the large scale universe could be considered to be empty and thus both the mass-energy density and pressure terms are zero. Assume here that Λ > 0. This shows an interesting result as it interprets the universe to expand exponentially (increasing acceleration of expansion) due to the presence of the cosmological constant. While it is an obvious notion that matter is present in the universe, de Sitter’s universe is yet a valid state of the universe as it represents a universe where the effects of the cosmological constant overcomes the effect of mass-energy density. In this model, as the universe expands at an accelerated rate, matter is spread apart more and more, thus resulting in the ambient temperature of the universe to drop. Eventually matter will be spread out so thinly that ρ → 0 and the temperature of the universe reaches absolute 0. This is considered as the “Heat-Death” of the universe. An arising question here is exactly what does this cosmological constant mean? While Einstein added the parameter as a form of counter-gravity to ensure that his field equation modeled a static universe (which was the accepted model at the time), this later became vital in describing the dynamics of the universe. Later studies related the cosmological constant to dark energy rather closely, using it as an explanation for the accelerated expansion of the universe. We can observe this through further examination of the Friedmann equations and the state equation for the universe. The Chronology of the Universe This representation of the first Friedmann equation and the introduction of three parameters for matter/ radiation (Ω ᴍ/R), dark energy (ΩΛ), and curvature (Ωk) provide an understanding into the origin, geometries, and possible time-evolutions of the universe6. The above relationship allows to model the evolution of the universe by deriving one parameter based on the knowledge of two. This can be summarized by the figure below7. 5 This is only due to ease of simplification here. However, similar results are obtained for = ±1 difference being that the results are to be interpreted in terms of the respective geometries. 6 The mathematical treatment here is rather simple. For example, taking Λ = 0 → ΩΛ = 0 we have Ω/ − 1 = Ω. If the observed density of the universe is less than the critical density then Ω/ < 1 giving Ω < 0 implying that = −1 or that the geometry of such a universe is open-ended. 7 By substituting into the 1st Friedmann equation for different cases of Λ, we can derive relationships to express the rate of change of expansion (slope of the () vs. graph).

ASTROSOC 53 The various models for the expansion of the universe that can be derived from the Friedmann equations along with the necessary parameters. A case of particular interest is the ΩΛ > 0, = 0 situation, which is what cosmologists believe to be accurately depicting the universe with current existing experimental data. This is also known as the Lambda-Cold-Dark-Matter (ΛCDM) model (image courtesy: (Lambourne, 2010)). In the future following Friedmann’s work, experimental evidence was published in 1998 showing that the universe was definitely expanding at an accelerated rate, which would only be possible if ΩΛ > 0. This was the first evidence for the presence of dark energy in our universe, and propelled the currently accepted ΛCDM model of the universe. Furthermore, experimental evidence suggests that the universe is mostly flat geometrically. And thus is an account of the field of cosmology, an ever growing study area with many a research opportunity. In the course of time, research into high-energy cosmic events, and mapping the expanse of dark energy in the universe will be fruitful for a better understanding of our universe. And perhaps, even result in the proposal of newer theories, propagating ripples of scientific thought and development through the minds of the community… REFERENCES: 01. Lambourne, R. J., 2010. Relativity, Gravitation and Cosmology. 1st ed. Cambridge: Cambridge University Press. 02. Schutz, B. F., 2009. A First Course in General Relativity. 2nd ed. Cambridge: Cambridge University Press. 03. Tong, D., 2019. University of Cambridge Lectures. [Online] Available at: http://www.damtp.cam.ac.uk/user/tong/gr.html [Accessed 2023]. W. M. D. A. L. B. Tilakaratna Demonstrator Department of Physics Faculty of Science University of Colombo.

ASTROSOC 54 The Glitch ‘Commander Broody, we are all set for departure’. My second in command said as I was staring out the window of our spaceship, mesmerized by the scene before me. 24 hours ago, a group of people managed to pass a massive milestone in the entire history of mankind. Those people were able to reach a place where no man ever has succeeded in arriving, since its first photographing in 1959. “A place that cannot be seen”. For a curious race like humans, those few words are enough to spark countless rumours and theories. They have attempted all possible ways to at least get a glimpse of this unseen territory and it was the Soviets who triumphed in that task. In 1959 the space probe ‘Luna 3’ successfully managed to deliver images of this place, clearing and clarifying the theories surrounding it. But that was just the beginning of a whole new obsession for curious minds. After numerous failed attempts, the project ‘Selene - V’ succeeded. What is Selene-V you ask? Well, that is a project to carry 5 people to a destination unknown to mankind. And I, ‘Commander Broody’, was chosen to lead the mission. ‘Isn’t it mesmerizing commander?’ Natan said as he tapped my shoulder to bring me back from my little reminisce. Natan is the second in command for this expedition mission. “Yes. It’s fascinating. Just like from the pictures, I would say,” I said letting out a little chuckle and walking out of the observation deck to the main lobby. In the lobby were my other crew members who were all suited up and prepared with the gadgets for the exploration. “Since everyone is ready. Let’s start our expedition.” I declared, officially commencing our adventure to explore the dark side of the moon.

ASTROSOC 55 A.Jalani J. Perera Level Four Undergraduate Faculty of Science We left our spaceship and started exploring the surface of the moon while gathering samples of the dust and rocks we found. Our team’s technical specialist Lesley was monitoring and recording all the signals and other types of waves that were in the atmosphere while Chris was capturing the moon’s surface through camera lenses. The surface was not far from what we had already seen from the pictures from ‘Luna 3’, ‘Apollo 8 ’, and ‘Yutu-2’. It was covered in craters of all sizes with no traces of lava flowing to the surface unlike in the Near side. The first day of the mission was completed without any hitches. “Alright everyone, we have completed all the tasks for today. Let’s head back to our ship to analyze what we have gathered,” I directed. After returning to the spaceship everyone went their separate ways to analyze the information they had gathered in their respective fields. I sat down on the observation deck’s couch and set my coffee aside on the table. As the commander, it was my responsibility to record the occurrences and enter the log about the exploration for the day. Since the day passed without any surprises or significant discoveries, the log was uneventful, and I managed to wrap it up without taking much time. I took my coffee back and started sipping it while gazing at the surface of the moon, where thoughts of the historic achievement of space exploration we accomplished lingered in my mind. My train of thought was interrupted by the figure of Natan barging into the deck. “Commander, Chris found something bizarre. You need to come and see it right away,” he gasped, trying to catch his breath. I bolted out the door following Natan into Chris’s chambers where he went to analyze the photos he took. There I found all my other crew mates gathered around a table that had a few photos scattered over it. “What happened?” I asked Chris, closing in on the table. “Take a close look at these two images.” he pleaded while handing me the pictures. Those images were almost identical shots of the parts we explored earlier today. Although their times of capturing were a few seconds apart, I was unable to detect any abnormalities between them. It took me a couple of minutes to notice something strange in one of the photos. I looked at Chris in bewilderment. Before my eyes was something beyond our known reality. In one of the images, there was a tiny part in it where it looked blurred. Almost similar to what a glitch in a computer display would look like. “But how can this be possible? Did you check your equipment? It could have been malfunctioning,” I said looking at Chris in utter disbelief. “No Broody. It wasn’t a fault caused by my cameras,” Chris replied shaking his head. “Do you think we are in a Fabricated space, like a VR?” Lesley murmured. The room fell into a dead silence as everyone was lost in thought about this bizarre discovery with their eyes glued to the two photographs in my hands. Image Credit: • https://cutewallpaper.org/22x/ q52i5tmd6/106882174.html • https://www.drewexmachina.com/2019/10/04/ luna-3-shedding-light-on-the-dark-side-ofthe-moon/

ASTROSOC 56 Generating much speculation and confusion, dark energy remains as one of the most elusive astrophysical phenomena to be unraveled. Its presence is inferred as a form of energy which accelerates the expansion of the universe. Another extreme feature, black holes are regions in space with gravity incredibly strong that even light is unable to escape from it. While the possibility of black holes being the source of said dark energy has been proposed for some time, recent experiments have sought to test this claim and quantify the strength of this relationship. the correlation between growth of a black hole’s mass and the accelerating expansion of the universe, whereby they propose that black holes are indeed the astrophysical origin of dark energy. New light on the dark… On 20th February 2023, the paper titled “Observational Evidence for Cosmological Coupling of Black Holes and its Implications for an Astrophysical Source of Dark Energy” appeared in The Astrophysical Journal Letters, to much acclaim by the Astrophysics community. The work was published by an international group of collaborators led by Duncan Farrah of the Institute for Astronomy, University of Hawai’i. The study claims to have found observational evidence for The dark, the black and the virtual By observations of the light from distant galaxies which are redshifted (doppler shift towards larger wavelengths), it is understood that the universe is not static but that it is expanding. Further observations showed that this expansion is also accelerating. Notably, this occurs in spite of the gravitation between objects which ought to pull them closer together, slowing down the expansion. Thereafter, the notion of “Dark Energy” was introduced as the driver of this rapid expansion. The paper makes the case that the famous Kerr black hole solution at infinity, is incompatible with an expanding universe. Models that are more realistic at infinity predict that the mass of a black hole can increase with the expansion of the universe, independent of the usual mergers and accretion of gas. This effect called An Unlikely Coupling: Black holes as sources of Dark Energy

ASTROSOC 57 at which the object becomes cosmologically coupled and k(≥0), the cosmological coupling strength. This constant k is a measure of relation of black hole mass increase relative to the rate of expansion of the universe. For a black hole with a gravitational singularity, this coupling strength should be zero. However, for the case of vacuum energy interior solutions to the black hole model; that is, if the black hole’s mass is coupled to the expansion of the universe, k~3 is predicted theoretically. Searching in the dark The team studied the growth of supermassive black holes in five dormant elliptical galaxies to compute their coupling strength k. Dormant galaxies were chosen because if a mass increase occurs in them, it should be due to the cosmological coupling and not standard black hole processes. The resulting probability distributions for k points to a most likely value of 3 and hence a combined result was inferred as k=3.11 with 90 % cosmologically coupled mass growth was in fact observed even in dormant galaxies, where there is insufficient matter to account for significant mass gains in the central black holes. Furthermore, it was deduced that the likely source of dark energy in the black hole context is the vacuum energy, a background energy that exists throughout the universe. Even inside vacuums, particle-antiparticle pairs named “virtual particles” pop in and out of existence and disappear promptly. Hence if this energy in any region of space (including vacuums) is measured, a small non-zero value ought to be found. Models and parameters General Relativity describes spacetime by a “metric” which determines the distances that separate nearby points and it is specified using a coordinate chart or grid that is laid down over all spacetime. The Robertson-Walker (RW) metric contains a scale factor which describes how the size of the universe changes over time. The paper points out that the way in which the black hole’s mass changes in time depends on the black hole model, and it is described in terms of the RW scale factor, the scale factor

ASTROSOC 58 confidence. Notably, the results exclude k=0 at 99.98 % confidence, greatly disfavoring the possibility of zero coupling and thus, the existence of singularity-containing black holes. Musings in the dark remnant black holes as the astrophysical origin for dark energy. The exact mechanism for this cosmological coupling, is however unknown and only theorized as of yet. Statistically promising and efficiently beautiful in marrying two elusive phenomena, more work will confirm if this result will indeed go down as a necessary revolution in the field of Cosmology. References • Farrah, D., Croker, K. S., Zevin, M., Tarlé, G., Faraoni, V., Petty, S., Afonso, J., Fernandez, N., Nishimura, K., Pearson, C., Wang, L., Clements, D. L., Efstathiou, A., Hatziminaoglou, E., Lacy, M., McPartland, C., Pitchford, L. K., Sakai, N., & Weiner, J. L. (2023c). Observational Evidence for Cosmological Coupling of Black Holes and its Implications for an Astrophysical Source of Dark Energy. The Astrophysical Journal, 944(2), L31. https://doi. org/10.3847/2041-8213/acb704 Holes yet to patch Pramudith Fernando Level Three Undergraduate Facalty of Science Motivated by the significant agreement of these results with other sources, the study makes the grand proposition that stellar With these results, the study proposes that these black holes contribute a cosmological constant energy density, as their masses increase proportionally to the expansion. This makes them suitable sources of dark energy, whose density is constant throughout spacetime. The study ventures to test whether all of the observed dark energy density ΩA is due to k~3 black holes. With the assumptions that black holes couple with k=3, that they are the only source of ΩA, and that they are made solely from the death of massive stars, it was found that the Illustration of a supermassive black hole located at the center of a galaxy total black hole mass is in fact consistent with the established dark energy density value of ΩA=6.8. https://cdn.spacetelescope.org/archives/images/screen/heic1419a.jpg Main Image: • https://unsplash.com/photos/an-artistsimpression-of-a-black-hole-in-the-sky9dhTSsEXc_M

ASTROSOC 59 What is meant by SBR? It would be more convenient if I started with the question, what are the benefits of conducting Space Biology Research (SBR)? In space, profound changes are made to the animal physiology. These changes mainly occur due to the change in gravity. Space radiation also plays a major role in this. All the organisms on Earth are adapted to functioning under the conditions of gravitational force. However, when they are in space the gravitational force is very low (microgravity). Therefore, in order to adapt to these new changes, the body goes through some physiological changes that affect the function of the organism. In addition to those factors that were mentioned above, organisms have adapted to the atmospheric pressures of Earth and periodic cycles of light and darkness over the past millions of years. Those conditions are altered in space crafts like the ISS (International Space Station). While cycling the earth at a speed of 17,130 miles per hour, the crew members of the ISS experience sunrise and sunset 16 times per day. Simply put, this could change the Circadian rhythm of any organism. The fundamental and most important objective of space biology research is to build a proper understanding of how spaceflight affects biological systems in space crafts, as well as in ground-based experiments that are designed to mimic the aspects of spaceflights. Through this research, scientists are trying to understand what are the biological mechanisms that organisms use to adapt to spaceflight and the alteration of gravity in general. Those experiments are designed to examine processes of metabolism, growth, stress responses, physiology, and development to get insight into how organisms repair cellular damages and protect themselves against infections and diseases in conditions of microgravity while being exposed to space radiation. After all, the ultimate goal of all of these efforts is to keep astronauts healthy during space missions. Research with Microbes Space is a very harsh environment. Scientists have done experiments in extremely harsh environments on Earth where they have found forms of microbes called Extremophiles. So, the question remains, could they survive in space? Rodents-One of the most commonly used model organisms Space Biology Research with Rodents and Microbes

ASTROSOC 60 To test whether they can survive or not in space, there are two ways. One is to expose them directly to actual space conditions. The second way is to expose them to simulated space conditions. Microbes can be either harmful or not. The balance between those two types is essential to maintain a healthy environment. For that, it is crucial to understand how microbes work in space. Especially because in space people live in very close, sealed environments, and because of that control of disease-causing harmful microbes is necessary while at the same time maintaining a balance between useful microbes. Types of microbes that are not harmful on the Earth could be harmful in space. Because the human immune system starts to degenerate due to microgravity conditions. Studies have shown that microorganisms experience a series of changes in their cell structure, metabolism, and growth patterns due to reduced gravity and lack of a solid surface. When considering how host cells and microbes behave in microgravity, in more advanced systems with both bacteria and human cells, microgravity can affect the way microbes interact with their host cells and cause cells to mutate, developing a higher resistance to immune defenses of the host. Another problem is bio-corrosive microorganisms. These microbes grow on metallic surfaces and have the ability to damage both equipment and hardware. Since the tools and the resources for a long-duration spaceflight are limited, understanding how such microbial species grow and interact with each other and metallic surfaces in this environment is essential. The situation that could arise because of these corrosive microbes is more deadly unlike in cruise ships on Earth. Presence of certain microbes may be important for the proper growth of some plants in space and also crucial for the production of bio-regenerative life support systems in the future. Therefore, developing an appropriate microbial ecosystem within the spacecraft is one of the vital things for the success of long-duration spaceflight missions. Research with Rodents Multiple interacting biological systems, including bones, muscles, heart, blood flow, and the immune system can be altered because of space. Hence, it is necessary to understand how such alterations affect the entire organism. This can be achieved by working with research model organisms such as mice and rodents. There are components of rodent biology that are directly related to human biology. Almost every gene found in humans has been found in closely related forms in rodents. This means there is a relatively high genetic similarity between humans and rodents. The effects of microgravity are observed to rapidly affect rodents because of their shorter life spans (shorter life cycles compared to humans). When studying rodents, scientists use both similarities and differences between humans and rodents to gain insight into changes brought about by space flights. In order to help those experiments, constantly conducted in space, scientists at NASA’s Ames Research Center in California’s Silicon Valley have developed the Rodent Research Hardware System. With the help of this equipment and protocols, scientists are able to partner with NASA to conduct a variety of experiments in the unique laboratory of the International Space Station, without the need to develop and test a new system for each mission. Figure 1_NASA’s Rodent Habitat module with both access doors open. NASA’s Ames Research Center in California’s Silicon Valley developed the hardware platform that allows scientists to perform valuable research with rodents in space. Rodent studies provide inform Credits: NASA/Dominic Hart

ASTROSOC 61 Some of the experiments that have been conducted in the laboratory of ISS are as follows. 1. Rodent Research 10, focuses on the effects of spaceflight on regenerative bone formation. Bone health depends on the process of tissue regeneration during which cells continue to break down and build up the structure of bones. Regenerative Homeostasis keeps the biological systems stable over time. Therefore, it keeps the bone structures stable as well. Bone disuse in microgravity and space radiation can rapidly disrupt this process. Simply it causes the bone tissue repair to malfunction, resulting in 1.5 % bone loss per month. Therefore, in order to maintain the bone mass, as a countermeasure, the crew on board the space station have to undergo extreme daily physical conditioning of about two hours. Here, researchers investigate the cellular and molecular mechanisms underlying the bone regenerative deficit due to disuse in microgravity. In terms of genetics, basically, the study investigates the role of a gene known as CDKN1A that produces the CDKN1A protein that inhibits cell cycle progression in cells. Expression of the CDKN1A gene is induced by both radiation and microgravity. 2. Rodent Research 23, the study of how spaceflights affect eyes. During long-duration space flights astronauts could experience eye conditions such as swelling of the eye nerve and folding or flattering of eyeballs. This could lead to the use of glasses and have the potential to affect astronauts on long-duration human space missions to destinations like Mars. Rodent Research 23 specifically studies the effects on the structure and function of the arteries, veins, and lymphatic vessels that are needed to maintain vision in rodents. Rodents that have spent around five weeks in space are examined for this purpose. Overall, the importance of these researches which are conducted in space is to increase the safety of astronauts as well as to improve their lives as they go on longer space expeditions. It is important to understand the effects of spaceflight over time, whether they get worse or better, whether they are permanent or revert back upon returning to Earth, and to determine whether there is any possibility to prevent the adverse effects before they appear or to at least lessen their impact on the astronauts’ health. References • https://www.nasa.gov/general/rodentresearch/ • https://www.nasa.gov/centers-and-facilities/ ames/ames-sends-rodents-cells-andmicrobes-to-space-station-on-spacexmission/ • https://science.nasa.gov/biological-physical/ programs/space-biology Image Courtesy • https://www.nasa.gov/wp-content/ uploads/2023/03/habitat_1_0.jpg • https://www.nasa.gov/wp-content/ uploads/2022/01/rr-hardware-systemacd13-0108-056-0-1-0.jpg?resize=2000,1119 • https://science.nasa.gov/_ipx/w_1536&f_ webp/https://smd-cms.nasa.gov/wp-content/ uploads/2023/04/rodent-cover-cropped_0- jpg.webp%3Fw=1400 Figure 2_The Rodent Research Hardware System includes three modules: (left) habitat, (center) transporter, and (right) animal access unit. Credits: NASA/Ames Research Center/Dominic Hart K. M. Dilan Lakshitha Kumarasingha Level Three Undergraduate Faculty of Science

ASTROSOC 62 Ptolemy cluster Butterfly cluster Galactic center The Cover Story 62

ASTROSOC 63 Lagoon nebula Trifid nebula Sagittarius star cloud This breathtaking image of the Sagittarius arm of the Milky Way was captured by Sahan Liyanage, a member of the Astronomical Society, on a fine night of June, 2022, using his Nikon D7500, Nikkor 18-140mm f/3.5-5.6 camera. Being one of the main spiral arms of the milky way, sagittarius arm can be seen to the naked eye as a faint band of light that stretches across the sky on a moonless dark night. This image represents a part of that arm, the region that lies within the sagittarius constellation. With the aid of a telescope, a binocular or a high resolution camera, you can get a view of this bright region, consisting of the gas and dust clouds. What lies behind these clouds is the Sagittarius A*, the supermassive blackhole at the heart of our galaxy. In addition to the galactic center and the sagittarius arm, this photograph has captured many deep sky objects, such as the Ptolemy cluster, Butterfly cluster, Lagoon nebula, Trifid nebula, and the sagittarius star cloud. © Sahan Liyanage Astronomical Society University of Colombo 63

ASTROSOC 64 Figure 1: AI-generated image of the multiverse Peeping into the Multiverse Exploring the Multiverse Theory and the Astonishing Possibility of Infinite Parallel Universes What is the Multiverse? Have you ever wondered how our universe was formed? What lies beyond what we see? Is our universe one out of many universes which could exist? If those exist, could there be other different versions of you living in different realities? These are some of the many questions that scientists, philosophers, and science fiction writers have been trying to seek answers to! The concept of the multiverse is not mere fiction, but also has some scientific basis in various theories that attempt to seek answers to these intriguing questions! In this article, we are going to embark on a journey to look at some of the main ideas behind the multiverse theory and unravel the mysteries and wonders of the so-called multiverse. The multiverse is a hypothetical collection of potentially diverse observable universes. It is the hypothetical set of all universes, which together are presumed to comprise everything that exists, including the entirety of space, time, matter, energy, information, and the physical laws and constants that describe them. (Aguirre, 2023) As Britannica.com states, the multiverse is the idea that beyond the observable universe, other universes may exist as well. The observable universe is the region of space and time that we can observe using modern technology. This doesn’t mean that there exists nothing beyond our observable universe. Despite the tremendous advancements of modern technology, we are humbled by the realization that our current capabilities still impose constraints on our understanding and exploration of the universe! There are different models of the multiverse that are predicted by scientific theories. Let us explore some of these fantastic theories: The Inflationary Multiverse: This theory is based on the idea that our universe had undergone a rapid period of expansion, called inflation, shortly after the Big Bang. During this process, it is assumed that different regions of space inflated at different rates, which eventually created bubbles of space-time that separated each other. It is assumed under this theory that each bubble became a universe with its own physical constants, initial conditions, laws, and different realities. (Linde, 2014) The Quantum Multiverse: This is based on the idea that quantum mechanics, the fascinating theory which describes the behavior of subatomic particles, allows multiple possibilities. These possibilities give rise to different parallel universes. For example, in a parallel universe, you may have become a celebrity! Let us take another interesting example, suppose you flip a coin, then

ASTROSOC 65 Figure 2: AI-generated image of the bubble universe there exists a universe where it lands head and another universe where it lands tail. (Siegfried, 2019) The String Theory Multiverse: Another interesting theory! The string theory is an interesting framework that tries to unify the particles of nature and all the forces. According to it, there are dimensions that we can’t observe beyond the three we know! It predicts that these dimensions may be curled up in different shapes and sizes. This further predicts that there exist many shapes resulting in different physical universes with different laws and realities. (Smolin, 1997) Figure 3: AI generated image of the universe as predicted by String theory Is there any evidence that supports the Multiverse Theory? While we have explored intriguing scientific theories about the multiverse, some may question its existence, dismissing it as nothing more than a creation of profit-driven science fiction filmmakers. Are there any pieces of evidence to support this theory? Let us continue our journey to seek whether there exists evidence! Although we talk about the multiverse, it is impractical to observe the so-called multiverse. However, there are few indirect ways to infer its existence! Scientists look for anomalies that could explain the existence of other universes! The cosmologist could discover that our universe is exquisitely fine-tuned. This means that the physical constants and initial conditions seem to have precise values for the existence of life. For example, if the electromagnetic force were slightly different, chemical bonds crucial for life’s complexity would not occur; if the cosmological constant were slightly different, the universe would either collapse or expand too fast for life to evolve, and many more. This leads us to a strange question, “Why are the physical constants and initial conditions precisely what they are?”, and “Why is our universe so special?”. As suggested by the multiverse theory, one of the possible answers is that it is not special, it is just one of the many universes with different values for those parameters, and luckily, we happened to live in this universe that supports life! (Carter, 1974) Now can you imagine how many possible universes may exist? Infinite, isn’t it?

ASTROSOC 66 Another piece of evidence that supports the existence of the multiverse is the cosmic microwave background. This refers to the radiation that is assumed to be left out by the big bang which fills the universe. It is observed to have the same temperature and intensity in all directions! However, tiny fluctuations have been observed, which are observed to be the seeds of the formation of galaxies and other structures in the universe. It is assumed that some of these fluctuations may be caused by quantum fluctuations during inflation, but some may also be caused by the interaction or collision of our universe with other universes. (Penrose, 2010) The multiverse theory has led to so many interesting consequences! It has a great deal of influence on our thinking. Are there other universes that exist, if they do, are they like ours? Could they contain copies of ourselves, living different lives and making different choices? Some may contain life forms that we cannot even imagine! The multiverse theory also raises some philosophical and ethical questions. Figure 4: AI generated image of the cosmic microwave background radiation ) What are the consequences of Multiverse Theory?

ASTROSOC 67 Kavinda Rashmadu Level Two Undergraduate Faculty of Science If there are many possible realities out there, does that make our existence less or more significant? Does it affect free will? How do we cope with the paradoxes and contradictions of the multiverse? If there are parallel universes where anything can happen, does that mean that logic and causality break down? These are some of the many questions that scientists and philosophers have been exploring. The multiverse theory is not just a concept but has some scientific basis. However, the multiverse theory is still controversial and there is no definitive proof about it. It may remain forever beyond our reach or comprehension, or it may one day be confirmed or refuted by new discoveries or experiments. Until then, we can only wonder and imagine what lies beyond our observable universe, and whether we are alone or not in this vast and mysterious multiverse. Let us end the fascinating journey we embarked on to unravel the wonders of multiverse theory here. In the end, the multiverse theory reminds us that our universe is a captivating playground for human imagination. References Image Courtesy • Aguirre, A. (2023, Jun 18). multiverse. Retrieved from britannica: https://www.britannica.com/ science/multiverse • Carter, B. (1974). Large number coincidences and the anthropic principle in cosmology. Confrontation of cosmological theories with observational data, 8. • Linde, A. (2014, Mar 9). Inflationary Cosmology after Planck 2013. Retrieved from arxiv: https:// arxiv.org/abs/1402.0526 • Penrose, V. G. (2010, November 16). Concentric circles in WMAP data may provide evidence of violent pre-Big-Bang activity. Retrieved from arXiv.org: https://arxiv.org/abs/1011.3706 • Siegfried, T. (2019). The Number of the Heavens. Cambridge: Harvard University Press. • Smolin, L. (1997). The life of the cosmos. Oxford: Oxford University Press. • Figure 1 :a realistic image of multiple parallel universes spreading far and far with less brightness - Image Creator (bing.com) • Figure 2: a realistic image of bubbles of spacetime that separated each other and became different universes with less color and brightness - Image Creator (bing.com) • Figure 3: a more realistic image of different shapes of curled up dimensions that result in different physical universes - Image Creator (bing.com) • Figure 4: a realistic image of the cosmic microwave background with tiny fluctuations and a collision of two universes - Image Creator (bing. com)

ASTROSOC 68 Observation of Solar Radio Bursts using CALLISTO Solar radio bursts are sudden, intense bursts of radio waves originating from the Sun. These bursts are often associated with solar activity and can provide valuable information about the Sun’s behavior. There are five types of solar radio bursts. Type I solar radio bursts are narrowband bursts of radio waves that occur at meter wavelengths. They are typically associated with solar flares and are caused by the acceleration of electrons in the Sun’s outer atmosphere, known as the corona. Type II solar radio bursts are broadband bursts that occur at decameter wavelengths. They are often associated with coronal mass ejections (CMEs), which are massive expulsions of solar material and magnetic fields from the Sun. These bursts are produced by shockwaves generated as CMEs travel through the solar corona and into the interplanetary medium. Type III solar radio bursts are narrowband bursts that occur at decameter or longer wavelengths. They are typically produced by fast-moving electrons in the Sun’s corona. Type III bursts are often observed in association with solar flares and can be used to trace the paths of accelerated electrons. Type IV solar radio bursts are broad, continuum bursts that occur at meter wavelengths. They are associated with the eruption of large solar flares and the subsequent formation of post-flare loops, which can emit synchrotron radiation at these wavelengths. Type V solar radio bursts are a rare type of burst that can occur during the decay phase of a solar flare. They often show complex spectral features and are not well understood. The following figure shows the different types solar radio bursts detected by the e-CALLISTO global network. Type II Type III

ASTROSOC 69 Solar radio bursts are detected by radio telescopes on Earth and in space, and they can provide valuable insights into solar activity and the processes occurring in the Sun’s atmosphere. The Compact Astronomical Low-cost Low-frequency Instrument for Spectroscopy and Transportable Observatory (CALLISTO) radio spectrometer is designed by the Institute of Astronomy, Switzerland to observe the radio wavelengths of solar flares emissions. The frequency range of the spectrometer is 45 MHz to 870 MHz. The instruments observe automatically, their data is collected every day via internet and stored in a central data base. A public web interface exists through which data can be browsed and retrieved. A total of 76 active instruments form a network called e-CALLISTO. It is still growing in the number of stations, as redundancy is desirable for full 24 hour coverage of the solar radio emission in the meter and low decimeter band. The e-CALLISTO system has already proven to be a valuable new tool for monitoring solar activity and for space weather research. Researchers use the characteristics of these bursts, such as their frequency, intensity, and duration, to study and better understand solar flares, CMEs, and the underlying mechanisms responsible for these phenomena. Studying solar radio bursts is an important part of space weather research, as they can impact communication systems, satellite operations, and power grids on Earth when intense solar activity occurs. The observation station in Sri Lanka is located at the Arthur C. Clarke Institute. The system consists of CALLISTO receiver, 6 m high Log-Periodic antenna and a pre-amplifier. The basic arrangement of log-periodic antenna (the figure below) is two-wire line array elements of dipole antennas with 180o phase shift. The design input parameters, theoretical gain of the LPDA, G=7 dBi, nominal input resistance R = 50 Ω and the frequency range 45 MHz, the lowest (fl ) and 600 MHz, the heights (fn ) were set to achieve the voltage standing wave ratio, VSWR < 1.5. The e-CALLISTO data archive is a public that anyone can use the data for research purpose. The data is available at https://www.e-callisto.org/Data/data.html repository. Profound Dr. Janaka Adassuriya Senior Lecturer Astronomy and Space Science Unit Department of Physics University of Colombo analysis of the solar radio bursts provides the unknown mysteries of solar phenomena. Therefore, this facility is vital to study the structure of solar flare, trigging mechanism and the potential of pre-monitoring of such events. The observation facility is being used by undergraduates to fulfill their final year research projects. Implementation of solar physics research through this kind system will widen the opportunities for the university students. The conditions in the solar wind in the Earth’s vicinity are now referred to generically as “Space Weather”. These conditions include the solar wind speed and density, magnetic field strength and orientation, and energetic particle levels. They are largely controlled by the Sun, which is the source of the solar wind as well as of coronal mass ejections that impact the Earth. Therefore, such phenomena should be predictable in order to minimize the hazard. The solar radio observation is a vital area in such a way that it supports understanding the nature of the violent events of solar flares and CMEs.

ASTROSOC 70 Observational Astronomy beyond the Electromagnetic Spectrum Since Galileo first aimed a telescope at the sky in 1609 AD, mankind’s knowledge of the universe has made dramatic improvements. Starting with the visible light region of the electromagnetic spectrum (EM spectrum), mankind expanded its ability to observe the universe in every region of the EM spectrum. But the curiosity of mankind to explore the universe deeply does not allow us to rely only on the EM spectrum. Based on the theoretical improvements in physics, people have tried to use new types of observational methods beyond the EM spectrum to observe the universe. Therefore, observational astronomy based on gravitational waves, neutrinos, and cosmic rays is a prominent example of this topic. This article explores only observational astronomy based on gravitational waves and neutrinos that have revolutionized our understanding of the cosmos, which lies beyond the reach of EM spectrum-based telescopes and observatories. In 1915, Einstein published a new theory called the Theory of General Relativity. With this theory, Einstein gave a new interpretation of gravity than Isaac Newton did more than 200 years earlier. According Gravitational waves propagate through spacetime itself without the need for any medium and interact weakly with matter. Consequently, they experience less scattering and attenuation compared to electromagnetic waves during their journey through space. There are four types of gravitational waves: Continuous GWs (produced by objects like neutron stars due to imperfections in axial symmetry), ComGravitational Wave Astronomy to Einstein’s theory, gravitational force is described as the curvature of spacetime caused by the presence of mass and energy. This interpretation gave an answer to why (and how) gravity creates an attraction force between masses that Newton’s law of gravitation did not explain previously. When masses are accelerating in spacetime, they create disturbances in spacetime, and those disturbances propagate through space at the speed of light. Those waves are called Gravitational waves (GWs). The existence of GWs was predicted by Einstein in 1916 based on his theory of general relativity. In theory, every accelerating object with mass produces gravitational waves. However, currently, it is only possible to detect gravitational waves produced by “violent and energetic cosmological events” due to technical limitations in current instruments. Binary systems of black holes or neutron stars, supernovae, and axially asymmetric spinning neutron stars are some examples of “violent and energetic cosmological events” that produce gravitational waves.

ASTROSOC 71 Figure 1: Romano, J. D., & Cornish, N. (2017, April 4). The gravitational wave spectrum. Living Reviews in Relativity. https://doi.org/10.1007/s41114-017-0004-1 pact Binary Inspiral GWs (produced by massive compact binary systems like binary black holes), Stochastic GWs (the most difficult GW type to detect, and a part of this type of GW is believed to be a relic from the Big Bang), and Burst Gravitational Waves (short, unexpected GWs, and there is still no accurate knowledge about these), each characterized by distinct sources and characteristic vibrations. As a result, different types of acceler

ASTROSOC 72 ating objects generate unique gravitational wave signals, allowing us to gather information about their sources (mainly about the dynamics of the system). In the propagation of GWs, they undergo only two significant alterations, namely redshifts (Doppler, gravitational, and cosmological) similar to those observed in electromagnetic waves (EM waves) and a reduction in amplitude resulting from the “inversesquare-law” spreading of wave fronts, which is also similar to the electromagnetic scenario. As a result, GWs can exhibit wavelengths ranging from the millimeter scale to many light years, with their amplitudes being exceptionally low. Consequently, despite GWs carrying a lot of data, detecting gravitational waves poses an immensely challenging task. The first detection of gravitational waves relied on indirect observation of a binary pulsar system. In 1974, Joseph Hooton Taylor Jr. and Russell Alan Hulse discovered the first binary pulsar (later known as the Hulse-Taylor pulsar). Subsequently, in 1981, they measured the orbital-period decay in this system, and the results aligned precisely with Einstein’s theory. For their groundbreaking discovery, they were awarded the 1993 Nobel Prize in Physics. The first direct observation of gravitational waves was made by the LIGO (Laser Interferometer Gravitational-Wave Observatory) detectors on September 14, 2015. A merger of two black holes generated those gravitational waves. This event, known as ‘GW150914’, occurred approximately 1.3 billion light-years away. Subsequently, the 2017 Nobel Prize in Physics was awarded for this direct detection of gravitational waves. Currently, there are two types of detectors that are widely used to detect GWs. 1. Interferometric Gravitational-Wave Detectors - Interferometry is the basic principle that is used in these types of detectors. These types of detectors, like LIGO detectors, have L-shaped arms with lasers traversing along them. As a gravitational wave passes through the detector, it induces subtle stretching and compressing of spacetime, resulting in minute changes in arm lengths. These alterations generate interference patterns in the laser beams, allowing for gravitational wave detection. However, creating this type of setup is challenging due to various types of noise sources and quantum effects. LIGO detectors (two identical detectors located in Livingston, Louisiana, and Hanford, Washington), Virgo (in Italy), and KAGRA (in Japan) are some examples. 2. Pulsar Timing Arrays (PTAs) - PTAs use precise timing measurements of pulsar signals to detect GWs. For this, a type of pulsar with a nearly constant rate of spin called a “millisecond pulsar” is used. As gravitational waves pass through the space between Earth and the pulsar, they cause tiny fluctuations in the arrival times of the pulsar signals. By monitoring multiple pulsars, researchers can detect correlated timing deviations caused by gravitational waves. Using these detectors, GWs in the nanohertz region (10-8–10-6 Hz) can be observed. The European Pulsar Timing Array (EPTA), the North American Nanohertz Observatory Figure 2: Abbott, B. P., Abbott, R., Abbott, T. D., Abernathy, M. R., Acernese, F., Ackley, K., Adams, C., Adams, T., Addesso, P., Adhikari, R. X., Adya, V. B., Affeldt, C., Agathos, M., Agatsuma, K., Aggarwal, N., Aguiar, O. D., Aiello, L., Ain, A., Ajith, P., . . . Bond, C. (2016, February 11). First gravitational wave event observation (GW150914) by the LIGO Hanford (H1, left column) and Livingston (L1, right column) detectors. Physical Review Letters. https://doi. org/10.1103/physrevlett.116.061102

ASTROSOC 73 Figure 3: Miller, M. C., & Yunes, N. (2019, April 1). Basic working principle of “L shaped” laser interferometer: a, laser generator. b, A “beam splitter” splits the laser beam into two identical beams. c, laser beam is reflected by mirrors. d, If a gravitational wave passes through one extends and the other contracts. e, Normally by interference light cancel each other out otherwise light hit the detector. Nature. https://doi.org/10.1038/s41586-019-1129-z. for Gravitational Waves (NANOGrav), and the Parkes Pulsar Timing Array (PPTA) in Australia unite to form the International Pulsar Timing Array (IPTA) to carry out this experiment. Currently, researchers all around the world are developing the technology and planning new detectors to expand the observational capacities of GWs in different frequency regions. The Einstein Telescope and the Cosmic Explorer are two new ground-based laser interferometry detectors currently under discussion. The Einstein telescope is an underground detector with a new design consisting of three laser beam tunnels and a higher resolution than current GW detectors have. Cosmic Explorer, a 40 km L-shaped observatory, is expected to develop based on new sets of technologies for better sensitivity and to reduce the quantum and thermal noises of the detector. A space-based detector called LISA (Laser Interferometer Space Antenna) is also planned to detect lower GW frequencies (10-4 to 10-1 Hz) than ground-based detectors currently achieve (10 to 103 Hz). The launch of LISA is planned for 2034.

ASTROSOC 74 Neutrino Astronomy According to the Standard Model of Particle Physics, all known matter is composed of two families of fundamental particles called Quarks and Leptons. Neutrinos are also fundamental particles and belong to the Lepton group. The neutrino family comprises three types (generally called “flavors”): electron (νe ), muon (νμ), and tau (ντ ) neutrino. Similarly, antiparticles also exist, for each “flavor” respectively. A distinctive characteristic of neutrinos is their electric neutrality. Among all known fundamental particles with mass, neutrinos are the lightest. Therefore, they are weakly affected by gravitational forces and also unaffected by strong forces (since they are leptons). The weak force influences them but acts over a short range. Consequently, neutrinos can pass through ordinary matter without any strong interactions. Name Reaction β- decay n→ p+e- +v̄e β+ decay p → n+e+ +νe β- capture p+e- → n+νe β+ capture n+e+ → p+v̄e Inverse Beta Decay (IBD) p+v̄e → n+e+ IBD on neutron n+νe → p+eTable 1: Common reactions involving electron neutrinos and anti-electron neutrinos (Rosso et al., 2018). After the discovery of neutrinos in 1956, they became ideal astronomical messengers due to their weak interactions with matter. Therefore, neutrino particles can travel vast cosmic distances. Currently, solar neutrinos, supernova neutrinos, and High-energy cosmic neutrinos are the main types of neutrino sources that are focused on in neutrino astronomy. However, detection is challenging due to their weak interactions, making massive particle detectors necessary to capture cosmic neutrinos in significant quantities. Solar neutrinos (SNs) are neutrinos generated through nuclear fusion occurring in the core of the Sun. There are two types of nuclear fusion processes (chain reactions) that can happen in a star: The proton-proton chain (PP Chain - the primary fusion process in stars like our sun) and the CNO Cycle (Carbon-Nitrogen-Oxygen Cycle - a main fusion process in more massive stars than our sun). Each of these processes produces neutrinos. Therefore, Studying SNs is essential to studying stellar evolution and developing a Standard Solar Model (SSM), a theoretical model to describe the internal structure, composition, and behavior of the Sun. The emission of neutrinos in supernovae is more complicated than the emission of SNs. At the core collapsing stage of massive stars (M≥8M◉- M◉ denotes the mass of the Sun), which exceeds the Chandrashekar limit (type II supernovae), emit enormous amounts of neutrinos into the universe. In that situation, about 99% of the gravitational binding energy is emitted in the form of neutrinos and antineutrinos of all flavors. Therefore, the process of stellar collapse into a neutron star or black hole can be studied using these neutrinos. High-energy cosmic neutrinos (HECNs) are elusive and enigmatic particles that originate from distant and powerful astrophysical sources in the universe. Currently, The sources and intensities of cosmic neutrinos remain uncertain, but active galactic nuclei (AGNs), gamma-ray bursts (GRBs), and some supernova remnants like extreme environments are believed to be the astrophysical sources of HECNs. Not only that but HECNs are also generated within Earth’s atmosphere through the decay of unstable particles (mesons) resulting from cosmic ray interactions with the atmosphere. Currently, to detect neutrinos, primarily two types of detectors are used: Scintillation Detectors and Cherenkov Detectors. In scin-

ASTROSOC 75 Figure 4: Katz, U., & Spiering, C. (2012, July 1). Measured and expected fluxes of natural and reactor neutrinos. Progress in Particle and Nuclear Physics. https://doi.org/10.1016/j. ppnp.2011.12.001 tillation detectors, when a neutrino interacts with scintillating material, an electron becomes excited, which it then de-excites by emitting a photon of light. That flash of light is detected and measured by light sensors surrounding the material. Cherenkov detectors detect Cherenkov radiation (electromagnetic radiation, mostly in the visible and ultraviolet regions, produced when a charged particle propagates in a dielectric medium at more than the speed of light in the medium). Suppose a neutrino engenders a charged particle (like in inverse beta decay) with sufficient kinetic energy to produce Cherenkov radiation, by capturing the emitted Cherenkov light, the neutrino’s properties can be analyzed. Generally, Neutrino detectors are placed deep underground or underwater to evade cosmic ray backgrounds and other disturbances. The first underwater neutrino telescope, DUMAND (Deep Underwater Muon and Neutrino Detector), started in 1976. That project failed, but this initiative laid the foundation for studying backgrounds and detector designs and emphasized the significance of neutrinos in astrophysics. Currently, there are many neutrino detectors and observatories around the world. Here are some examples of the main observatories: 1. IceCube Neutrino Observatory: Situated in Antarctica, IceCube is the largest neutrino detector, consisting of a cubic-kilometer particle detector instrumented with photomultiplier tubes (PMTs) to detect Cherenkov radiation produced by neutrino interactions. 2. Super-Kamiokande: Situated in Japan, Super-Kamiokande is a massive water Cherenkov detector containing 50,000 tons of ultra-pure water and equipped with PMTs. 3. SNO+ (Sudbury Neutrino Observatory Plus): Situated in Canada, SNO+ Experiment, successor to SNO, is a 2km underground detector that uses a liquid scintillator detector. So far, a lot of groundbreaking observations have already been made in neutrino astronomy. The first observation of supernova neutrinos was made on February 23, 1987, by Kamiokande, IMB, and Baksan detectors. These neutrinos emitted from a supernova (SN 1987A) happened in the Large Magellanic Clouds, and those detectors detected 12, 8, and 5 neutrino interactions, respectively, which are also consistent with theoretical predictions. Solving the solar neutrino problem and the discovery of neutrino oscillations are some other discoveries made in neutrino astronomy. There is still a lot to discover in neutrino astronomy. The Cosmic Neutrino Background (CNB) is one of the main hypotheses of the standard cosmological model. It is background neutrino radiation containing low-energy neutrinos from the Big Bang. There is no direct evidence for the CNB, but detection of the CNB is important because it gives information about the early Universe at approximately 1 second after the big bang, although Big Bang Nucleosynthesis and the Cosmic Microwave Background provide information about the early Universe at around a few minutes and 300,000 years old, respectively. Not only that, some theories hypothesize the contribution of neutrinos to dark matter as well (ex: sterile neutrinos).

ASTROSOC 76 In conclusion, gravitational waves and neutrino astronomy allow us to study the most energetic and distant phenomena in the universe by revealing hidden cosmic events that we cannot observe with the EM wave spectrum and offering unique insights into astrophysical processes and fundamental particle physics. Not only that, but they also allow us to test our theories in extreme situations. With cutting-edge detectors and ongoing advancements, both of these fields promise to unveil novel cosmic mysteries, pushing the boundaries of our understanding of the cosmos. Figure 6: Hirata, K., Kajita, T., Koshiba, M., Nakahata, M., Oyama, Y., Sato, N., Suzuki, A., Takita, M., Totsuka, Y., Kifune, T., Suda, T., Takahashi, K., Tanimori, T., Miyano, K., Yamada, M., Beier, E. W., Feldscher, L. R., Kim, S. B., Mann, A. K., . . . Cortez, B. (1987, April 6). The time sequence of events in a 45-second interval, centered on 07:35:35 UT, 23 February 1987 by Kamiokande II detector which associated with SN1987A. The vertical height of lines represents relative energy, while solid lines represent low-energy electron events (as the number of hit PMTs on left-hand scale) and dashed lines represent muon events (on right-hand scale). Physical Review Letters. https://doi.org/10.1103/physrevlett.58.1490 References • Miller, M. C., & Yunes, N. (2019b). The new frontier of gravitational waves. Nature, 568(7753), 469–476. https://doi.org/10.1038/s41586-019-1129-z. • Gravitational waves. (n.d.). LIGO Lab | Caltech. https:// www.ligo.caltech.edu/page/gravitational-waves. • Press, W. H., & Thorne, K. S. (1972). Gravitational-wave astronomy. Annual Review of Astronomy and Astrophysics, 10(1), 335-374. • Schutz, B. F. (1999). Gravitational wave astronomy. Classical and Quantum Gravity, 16(12A), A131–A156. https://doi.org/10.1088/0264-9381/16/12a/307. • Barish, B. C. (2022). Gravitational Waves—A new window on the Universe. Frontiers for Young Minds, 10. https://doi. org/10.3389/frym.2022.858203. • Rosso, A. G., Mascaretti, C., Palladino, A., & Vissani, F. (2018). Introduction to neutrino astronomy. The European Physical Journal Plus, 133(7). https://doi.org/10.1140/epjp/ i2018-12143-6. • Totsuka, Y. (1992). Neutrino astronomy. Reports on Progress in Physics, 55(3), 377–430. https://doi.org/10.1088/0034- 4885/55/3/002. • Mezzacappa, A. (2005). ASCERTAINING THE CORE COLLAPSE SUPERNOVA MECHANISM: the state of the art and the road ahead. Annual Review of Nuclear and Particle Science, 55(1), 467–515. https://doi.org/10.1146/annurev. nucl.55.090704.151608. • Yanagisawa, C. (2014). Looking for cosmic neutrino background. Frontiers in Physics, 2. https://doi.org/10.3389/ fphy.2014.00030. • Schoppmann, S. (2022). Review of Novel Approaches to Organic Liquid Scintillators in Neutrino Physics. Symmetry, 15(1), 11. https://doi.org/10.3390/sym15010011. • What’s a neutrino? | All Things Neutrino. (n.d.). https:// neutrinos.fnal.gov/whats-a-neutrino/. • Neutrino Astronomy. (n.d.). https://www.phys.hawaii. edu/~jgl/nuastron.html. W. D. Ravindu Kalhara Level Three Undergraduate Department of Physics Faculty of Science

ASTROSOC 77 Collided, The Shooting Star Taasha Hewa Matarage Level One Undergraduate Faculty of Science Spesh, sparkling brightly Yes, brightly than the moon, The beauty rising from Ashes, The shooting star, amidst thousands of stars, Delighted and contented with merry while Holding aroused hopes; It whispered, “Let me bring you Luck!” The tears of the moon, The gift from heaven, The shooting star, with very while, It disappeared 77

ASTROSOC 78 Figure 1. Visualization of Quantum Fluctuations; A depiction of the spontaneous and temporary fluctuations in the quantum field, highlighting the inherent uncertainty and dynamic nature of the quantum realm. https://www.pxfuel.com/en/ qury?q=quantum+fluctuation. T he human need for knowledge and understanding has driven scientific progress throughout history, challenging conventional paradigms and introducing new frameworks that transform our understanding of the natural world. Albert Einstein’s special theory of relativity, which combined space and time into a spacetime continuum, was a crucial paradigm shift. The rejection of absolute time led to the concept of mass-energy equivalence and relativistic mechanics. The discovery of quantum mechanics by visionaries like Schrödinger, Dirac, and Heisenberg established the concept of observables as operators and the basic constraint that non-commuting operators cannot be measured concurrently. The revelation of four fundamental forces, including gravity, has altered our scientific knowledge. Gravity, first described by Newtonian physics, underwent a transformation with Einstein’s general theory of relativity, transforming the spacetime arena of special relativity into a dynamic one, allowing gravitational forces to control the cosmic dance. Since the emergence of these two paradigms, physicists have harboured a fervent desire to reconcile and unify them, aiming to encompass the entireStellar Enigma: Decrypting the Cosmic Fade - A Journey through Hawking’s Riddles and Schwinger’s Shadows ty of physics. One of the earliest attempts at unification was put forth by Dirac through his suggestion of a relativistic quantum mechanical wavefunction. Dirac’s equation, resembling Schrödinger’s equation, not only hinted at the existence of antimatter but also laid the foundation for the development of Quantum Field Theory (QFT). In his seminal paper on “The quantum theory of the emission and absorption of radiation” published in 1927,

ASTROSOC 79 Figure 3. ESA [ESA] & NASA [NASA]. (2017, August 7). This computer-simulated image shows a supermassive black hole at the core of a galaxy. The black region in the centre represents the black hole’s event horizon, where no light can escape the massive object’s gravitational grip. The black hole’s powerful gravity distorts space around it like a funhouse mirror. Light from background stars is stretched and smeared as the stars skim by the black hole. https:// www.nasa.gov/image-feature/computer-simulated-image-of-a-supermassive-black-hole Figure 2. (n.d.). Andre Pattenden. Professor Hawking pictured at work in his department. www.cam.ac.uk. https://www.cam.ac.uk/stories/HawkingArchive Dirac addressed the inception of QFT, which offers an intriguing framework to describe the captivating phenomenon known as “Quantum fluctuations.” Within the realm of QFT, quantum fluctuations manifest as the fleeting appearances and disappearances of virtual particles, merely scratching the surface of the vast intricacies that lie beneath. When discussing grand unification and the theory of everything, the name Stephen Hawking stands out, and we simply cannot overlook it. He is undeniably one of the greatest scientific minds to have ever lived, a human whose dedication knew no bounds, even as his body’s muscles ceased to function. His remarkable intuition led to arguably the most significant strides in theoretical physics, aiming to unite Einstein’s theory of gravitation with quantum physics into a comprehensive theory of everything. His groundbreaking work on black holes, known as Hawking radiation, stands as a testament to his brilliance in unravelling the mysteries of the universe. When matter falls into a black hole, driven by its immense gravitational pull, it becomes isolated from the rest of the universe. This phenomenon contradicts the second law of thermodynamics. Recognizing this conundrum, a Princeton graduate student named Jacob Bekenstein put forth a proposal; the event horizon of a blackhole should increase its area as matter enters. Bekenstein argued that this increase in area represents the measure of entropy that would otherwise be lost. Initially skeptical of this idea, Hawking delved into the depths of black hole physics and made a remarkable discovery. His findings revealed that black holes indeed shine with cold light, now famously known as Hawking radiation.

ASTROSOC 80 NWO, Radboud University Nijmegen & Wikipedia. (2017, August 7). From left to right: Dr. Michael Wondrak, Prof. Walter van Suijlekom, Prof. Heino Falcke. https:// www.ru.nl/en/people/wondrak-m, http://www.waltervansuijlekom.nl, https:// commons.wikimedia.org/wiki/File:HeinoFalcke2011.jpg This breakthrough validated Bekenstein’s proposal and unveiled a previously unknown aspect of black hole behavior. In brief, Hawking radiation can be explained as follows. Within the realm of quantum fluctuations in the vacuum, virtual particles naturally arise and quickly annihilate each other. However, in the vicinity of a black hole’s intense gravity, these particles can become separated. This prevents them from recombining and results in one half of each particle–antiparticle pair escaping as radiation. According to Hawking, fleeting virtual particles, influenced by the extreme gravity near the event horizon, undergo a splitting process where one half of the pair gains negative energy and escapes, effectively reducing the mass of the black hole. This intricate interplay between gravity and quantum mechanics has been questioned, as the concept of splitting across an imaginary line can be misleading. Hawking’s conclusions shed light on how the curvature of spacetime near the event horizon can merge with quantum properties, ultimately leading to the evaporation of black holes. In June 2023, theoretical research conducted by Michael Wondrak, Walter van Suijlekom, and Heino Falcke from Radboud University reaffirmed Hawking’s insights on black holes. The study explores Hawking radiation and its role in the eventual disappearance of black holes, also raising questions about the significance of the event horizon. Interestingly, their research focuses more on the Schwinger effect, a phenomenon in electromagnetism. According to the Schwinger effect, strong electromagnetic fields can spontaneously create electron-positron pairs, akin to virtual particles, with one half managing to escape, leading to the decay of the fields. Van Suijlekom suggests that it is the steep curvature of spacetime, rather than the event horizon or black holes themselves, that plays a crucial role in the escape of radiation. Their research demonstrates that while the rate of particle production is highest

ASTROSOC 81 Matteo Ceccanti & Simone Cassandra. (2022, January). Schwinger effect seen in graphene: The electron–hole creation process that occurs after electrons are accelerated to very high velocities. https://physicsworld. com/a/schwinger-effect-seen-ingraphene Shutterstock. (2020, August 28). Black hole “hair” could be detected using ripples in spacetime and Hair may record the information swallowed by the gravitational monsters. https://www.livescience.com/black-hole-hair-gravitational-waves.html. at small distances in a Schwarzschild spacetime, the escape probability is highest at larger distances, which they eloquently illustrate in their paper using escape cones. Furthermore, according to Falcke, the concept of Hawking radiation extends beyond objects with event horizons, encompassing entities like neutron stars, potentially white dwarves, and massive galactic clusters with powerful gravitational effects. Ultimately, this could lead to the evaporation of the universe, similar to the fate of black holes. Pondering questions is an essential driver of scientific progress, and like any theory, it leaves room for numerous inquiries. One immediate question that arises is how this new finding impacts Hawking’s paradox. To understand this mystery, let me briefly explain its essence. According to general relativity, we can only ascertain certain properties of a black hole, such as its mass, charge, radius, and angular momentum (spin), but we cannot obtain any information from inside the black hole itself. Consequently, it does not matter how a black hole was formed or what objects contributed to its mass; if two black holes possess identical mass, charge, and angular momentum, they are considered indistinguishable, regardless of their origins. This implies that black holes lead to a loss of information from the broader universe. Before the formation of a black hole, in principle, we could gather extensive information about the events occurring in that region. However, once a black hole is formed, this information becomes inaccessible. Nevertheless, there is a glimmer of hope that the information may still exist within the black hole, albeit only accessible to entities within it beyond the event horizon, provided they can withstand the extreme gravitational forces. The emergence of Hawking radiation and the notion of black hole evaporation exacerbated this problem. Even though radiation is emitted, it does not contain

ASTROSOC 82 Youhan Wanigasuriya Level Three Undergraduate Faculty of Science References Image Coutesy In a paper published in 2022, researchers discuss a possible explanation for this question. They propose that the gravitational field generated by a black hole extends far beyond its immediate vicinity. Even in Newtonian gravity, objects with mass create a gravitational field that weakens with distance, but never truly reaches zero. Interestingly, this explanation delves into the concept of gravitons, the hypothetical gravity-carrying particles in the standard model. The researchers explore the quantum mechanical state of a black hole and find that the gravitational field it produces far away is dependent on the wave function of the black hole. This wave function relates to information that is otherwise inaccessible in the framework of general relativity. Given this new understanding of black hole evaporation, could we apply the notion of information loss to other celestial bodies as well?If so, just as gravitons may explain information loss in black holes, could the Schwinger effect, which involves photons as electromagnetic force-carriers, explain information loss in an evaporating universe? Is this a possibility of uncovering the hypothetical gravitons which could eventually contribute to the development of a grand unification theory ? A theory of everything. Wondrak, M. F., van Suijlekom, W. D., & Falcke, H. (2023). Gravitational pair production and black hole evaporation. Physical Review Letters, 130(22), 221502. Calmet, X., Casadio, R., Hsu, S. D., & Kuipers, F. (2022). Quantum hair from gravity. Physical Review Letters, 128(11), 111301. Semenoff, G. W., & Zarembo, K. (2011). Holographic schwinger effect. Physical review letters, 107(17), 171601. cover image : https://www.syfy.com/sites/syfy/ files/styles/scale_600/public/2022/01/gettyimages-758305399.jpg https://www.pxfuel.com/en/query?q=quantum+fluctuation. https://www.cam.ac.uk/stories/HawkingArchive https://www.nasa.gov/image-feature/computer-simulated-image-of-a-supermassive-black-hole https://www.ru.nl/en/people/wondrak-m, http://www. waltervansuijlekom.nl, https://commons.wikimedia. org/wiki/File:HeinoFalcke2011.jpg https://physicsworld.com/a/schwinger-effect-seenin-graphene https://www.livescience.com/black-hole-hair-gravitational-waves.html. all the information, as it is independent of the events occurring within the black hole. Consequently, with evaporation, the information is irretrievably lost.

ASTROSOC 83 THE FERMI PARADOX Are We Truly Alone in the Universe? Drake’s Equation Ever since the dawn of civilization, humanity has strived to make sense of the universe and its intricacies, throughout the centuries, as we gradually began to delve deeper into its workings, humanity was struck with one fundamental question: are we alone in this vast universe? In the 1950s, on one summer afternoon, during a discussion with his colleagues, this was the very question that gripped the physicist Enrico Fermi, where is everybody? Simply put, he wondered if we were truly alone in this universe, and if we weren’t, how was it possible that humans never detected even the slightest flicker of signs of life elsewhere. Despite it being an offhand comment, this profound question came to be known as the Fermi Paradox and it became a topic of discussion and aroused the curiosity of many; simply put, is humanity truly alone in this vast cosmos? Figure 1: The Milky Way Building upon Fermi’s original question, in 1961, an astronomer named Frank Drake proposed a formula that could theoretically calculate the number of civilizations currently sending signals in the Milky Way. N = R* × f p × ne × fl × fi × fc × L N : the number of civilizations with which humans could communicate R* : annual formation rate of stars hospitable to planets where life could possibly develop f p : : fraction of those stars with planets ne : number of planets per solar system with conditions suitable for life f l : fraction of planets suitable for life on which life actually appears f i : the fraction of planets with life on which intelligent life emerges f c : the fraction of planets with intelligent life that develops technologies such as radio transmissions that we could detect L : average length of time in years that civilizations produce such signs

ASTROSOC 84 The Kardashev Scale The Great Filter Another possibility, both chilling yet intriguing as to why we have no signs of life yet is the great filter theory, which postulates that every civilization faces a barrier that ends up in them being destroyed, either through external causes such as an asteroid hitting the planet or through internal causes such as climate change or nuclear war, before they gain the capability for intergalactic travel or communication. In 1964, Soviet astronomer Nikolai Kardashev proposed a scale that could measure just how advanced a civilization could be by its energy usage, by which intelligent life is divided into 3 categories. Type 01- A civilization that is able to utilize all the energy on its home planet and store it for consumption. Our earth is on its way to being a type 1 civilization. Type 02- A civilization that can directly consume the energy of the sun, theoretically The commonly cited numbers for these variables simplify the equation to N = 10 × 0.5 × 2 × 1 × 0.1 × 0.1 × L, which simplifies it even further to N = L/10. As we have been broadcasting into space since 1974, even if humanity ceases to exist in 2074, there could be 10 possible intelligent civilizations in our own galaxy within that time frame. Although this number offered a glimmer of hope that life could possibly be out there, in 2023, despite having cutting-edge technology that is capable of detecting the most minute signals, we are yet to find any definitive signs of life. This equation only focuses on the possibility of life in our own galaxy, yet there remains the possibility that somewhere out in one of the numerous galaxies, there might be some form of life, yet unless humanity invents advanced spacecrafts capable of intergalactic travel or makes breakthroughs in quantum communication that allows for speedy communication with other galaxies millions of light years away, that remains a futile endeavor. Figure 2: Proposed image of types of civilizations Figure 3: The Great Filter with timelines of civilizations through a Dyson sphere. Type 03- A civilization that has mastered the capability of harnessing all the energy of its own galaxy, even from objects such as black holes and stars.etc This classification yet again attempts to understand possible other civilizations and their technological capabilities, and how the categorization could affect their possibility of being found or discovered, nevertheless it still remains one of many possibilities. Despite countless years of research into intergalactic life forms and space travel and communication, the great question posed by Fermi remains unanswered. If life exists outside of our planet, have we missed all the signs? Are we incapable of recognizing signs of life elsewhere, or are we searching for the wrong signs? Is it possible that we are simply not advanced enough to understand communication or signs from a sufficiently advanced species? We have yet to unravel the secrets

ASTROSOC 85 W.S. Thishakya De Silva Level One Undergraduate, Faculty of Science. Regardless of whether we will ever find an answer to Fermi’s original question, the fact remains that so far we are the only life detected in this galaxy. To paraphrase Carl Sagan, every young couple in love, every mother and father, hopeful child, inventor and explorer, every saint and sinner in the history of our species lived here on a mote of dust suspended in a sunbeam; this might be the only form of life we’ll ever know. References Image Courtesy • Lohnes, K. (n.d.). The Fermi Paradox: Where Are All the Aliens? Encyclopedia Britannica. https://www. britannica.com/story/the-fermi-paradox-where-areall-the-aliens • Society, P. (2021b, September 9). The Fermi paradox and Drake equation: Where are all the aliens? The Planetary Society. https://www.planetary.org/articles/fermi-paradox-drake-equation • Society, P. (2020, October 30). A Pale Blue Dot. The Planetary Society. https://www.planetary.org/worlds/ pale-blue-dot • Whitt, K. K. (2022). What is the Great Filter, and can we survive it? EarthSky | Updates on Your Cosmos and World. https://earthsky.org/space/avoiding-the-great-filter-earth-alien-civilizations/ • Fig 1.Cover image https://bit.ly/3NqMYcH • Fig 2.https://bit.ly/3Xp1qpX • Fig 3.https://bit.ly/3pnRl03 • Fig 4. https://go.nasa.gov/43SNhEf Figure 4: The Milky Way of this cosmos and we may be still too young of a civilization to recognize other life forms. The other possibility, even more chilling and profound, is that we are truly alone in this cosmos.We, an advanced civilization on a small planet that appears as a mere speck; a pale blue dot in the Milky Way, could possibly be the one and only planet that harbors life that is sentient enough to ask these questions, and to ponder over their implications.

ASTROSOC 86 Galilean Moons Twas in Italy, the year sixteen ten A man named Galileo, looked up when Through his telescope, he saw in the sky Four satellites, that great things imply. Artemis’ aide, deep cratered Callisto Hera’s priestess, the innermost Io Zeus’s cupbearer, icy Ganymede Phoenician beauty, Europa sweet. Twas believed, Earth centred the universe No one accepted poor Copernicus, Yet here were moons orbiting Jupiter Enough to make geocentrists falter. ASTROSOC 86

ASTROSOC 87 Shehara De Silva Level Two Undergraduate. Faculty of Science And lo Io, with all its volcanoes, Plumes of sulfur and molten iron cores Next is Europa, smaller than the Moon With inner water and surface ice, strewn. Big huge Ganymede, icy hence lightweight Deep down a salt ocean, in liquid state And here’s Callisto, silicate rock rife With a thin atmosphere, there’s possibly life. The much acclaimed, four Galilean moons Named after four, over who, God Zeus swoons The first, third, fourth, sixth largest satellites In the Solar System, they’re truly mights. ASTROSOC 87

ASTROSOC 88 INTERVIEW A Talk with Dr. Henry Throop The members of the Astronomical Society of the University of Colombo have received many privileged instances to meet and learn from both local and international wellreputed figures in the field of astronomy. Let it be a deep scientific discussion or a casual conversation, the knowledge and wisdom we can gain from them are immense. Dr. Henry Throop is one such humble individual who always likes to spare his time to join us and share his insights. Coming all the way from the USA, he is a Program Scientist in the Planetary Science Division at NASA Headquarters. He also leads NASA’s Planetary Mission Senior Review and is the NASA POC for the Outer Planets Assessment Group. He has published over 40 articles in scientific journals, focusing on a diverse range of topics like planetary rings, planet and star formation, astrobiology and the origins of life, searching for and co-discovering Pluto’s smallest moon, Styx. However, his contributions to astronomy do not limit to space missions. Dr. Throop has spent much of his time bringing astronomy to the developing world, connecting with schools, universities, and community groups, helping to develop their science programs, and inspiring the next generation of leaders. With his help, most students were able to see the field of astronomy as an achievable career option, rather than just a hobby. Dr. Throop is no stranger to the members of the Astronomical Society, as we have presented many webinars and seminars with him throughout the past years. This interview will peek not only into the subject matter, but also into his life as a scientist, and what helped him to be such a successful individual in life. Q: They say every journey needs a first step. As someone who’s going through a very fascinating journey, we would love to hear about your first step in astronomy and that journey so far. Sure, so I grew up in the United States, and I went to university to study Physics. When I was studying physics, I had the opportunity to do summer research one summer, for doing astronomy. And I thought, “Wow!! this is so cool!”. I had never really done any astronomy before that summer research project. But that summer I got to work with other astronomers, visit some telescopes, and work with data from large telescopes, and I thought, “Wow! This is so neat”. Soon after that I took the chance to apply to postgraduate programs and I applied to a bunch of them, but I didn’t get into most! But I got into one of them, and that is University of Colorado for Astrophysics and Planetary Science. So I ended up going there, and it was terrific, it made me really enjoy astronomy and I’ve been doing it since then. What’s more exciting than following the work of scientists in your favorite field? Meeting and learning from them in person! ASTROSOC 588