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STELLAR CHRONICLE 51 . densities of water and silicon are both very high. Super-Earths with a radius of up to 1.5 Earth.Ocean planets or rocky planets with a sparse atmosphere are likely candidates for radii. Because we don’t have anything like in our own solar system, the true nature of these planets is unknown. They are exoplanets with temperatures hot enough to melt metal that have been discovered.Kepler-452b was the first planet of Earth’s size discovered orbiting a near-solar twin.Kepler-22b is a super-Earth that may be engulfed by a massive ocean. They may be lurking on the outskirts of our solar system. Just 6 light-years distant, a faint, frozen super-Earth orbits a fast-moving star. 4.4 Terrestrial planets: Terrestrial planets are smaller than Earth and made of rock, silicate, water, or carbon. More research will be done to see if any of them have atmospheres, oceans, or other signs of habitability. UL SPACE CLUB

STELLAR CHRONICLE 52 . Terrestrial planets are smaller than Earth and made of rock, silicate, water, or carbon. More research will be done to see if any of them have atmospheres, oceans, or other evidence of habitability .Earth, Mars, Mercury, and Venus are all terrestrial, or rocky, planets in our solar system. Terrestrial planets are those that are half the size of Earth and have a radius equal to or greater than twice that of Earth, however some may be significantly smaller. Our galaxy could include more than 10 billion terrestrial planets. The TRAPPIST-1 system’s seven Earth-size planets are considered to be terrestrial (4 are super-Earth size).In binary (two-star) systems, habitable terrestrial planets may exist.Kepler-11b is a terrestrial planet that orbits its star 10 times closer than Earth orbits the Sun. 5. Habitable Zones The majority of the discussion of habitable planets has been on Earth like planets with globally abundant liquid water. The surface of an \"aqua planet\" like Earth freezes if it is too distant from its sun, and the water will evaporate due to greenhouse effect if it is too close. The habitable zones of \"land planets\" (desert worlds with limited surface water) are larger than those of aqua planets. A land planet has two benefits over an aqua planet; for planets near the inner border of the habitable zone: 1. The air in the tropics is unsaturated, thereby it can emit longwave radiation at rates exceeding the usual runaway limit. 2. The dry air forms a dry stratosphere that inhibits hydrogen escape. Because there is less water for clouds, snow, and ice near the outer edges of the habitable zone, the land planet is better suited to withstand global freezing. Without initially passing through a sterilising runaway greenhouse, an aqua planet like Earth might lose most of its hydrogen and become a land world when the Sun brightens. Venus could have been a livable land planet as recently as one billion years ago. The majority of past studies of the habitable zone implicitly assume an ocean-covered planet with plenty of liquid water, similar to Earth. A planet like this is known as an \"aqua planet.\" The aqua planet will become completely frozen if it is too far away from its star. When an aqua planet, such as Venus in the past, gets too close to its star, the atmosphere fills with water vapour (steam). This causes a greenhouse effect to spiral out of control, resulting in the entire evaporation of the oceans. However, before the seas evaporate, the atmosphere becomes humid at all elevations, the cold trap dissipates, and UL SPACE CLUB

STELLAR CHRONICLE 53 . hydrogen escapes quickly. This sets off a race between evaporation and hydrogen loss to space. The end consequence would be a dry planet in either situation. Another type of habitable planet with little water and no oceans; it may be covered in enormous dry deserts, but it may also have rich water locally. A \"land planet\" is a dry world like this. On land planets, the runaway greenhouse effect has never been discussed before. Because air circulation regulates the latitudinal surface water distribution, the greenhouse effect of a land planet differs from that of an aqua world. On a land planet, the tropical atmosphere and stratospheric atmosphere can both be exceedingly dry, therefore runaway greenhouse and hydrogen escape thresholds may not apply. Climate Mode: It is considered that water encased in deep aquifers and hydrous minerals does not evaporate, contributing to a greenhouse effect. Rainfall, evaporation, and snowmelt are all expected to contribute to the shift in soil moisture. The rate of evaporation from the soil surface is a function of the soil wetness and the \"potential evaporation,\" or the hypothetical rate of evaporation from a completely wet surface.\" The bulk formula is used to determine the potential evaporation from the surface, which is proportional to the surface wind and the difference in absolute humidity between the air and the surface. The surface is judged to be entirely wet when soil moisture surpasses 10 cm. The evaporation rate is believed to be proportionate to the soil moisture when the soil moisture is less than 10 cm. The snowpack is represented as a single reservoir, the amount of which is predicated on the balance of new snowfall and snowmelt. When the surface skin temperature rises over the melting point, snowmelt occurs. Limits of Habitability: 1. Cold outer limit There are three possible surface states of a cold planet. (a) There is no permanent ice or snow on the planet. Ice and snow may be present during certain seasons. (b) As on Earth today, permanent ice or snow partially covers the planet. (c) The whole surface of the planet is covered in permanent ice or snow. This \"snowball\" state could have happened on early Earth. Snowball Earth does not appear to have caused a mass extinction on Earth (oxygenic photosynthesis appears to have survived); biota may have survived in the subsurface and in liquid water oases. It is assumed that when the Sun is dimmed to 77 percent of the solar constant (the current level of sunlight incident on Earth), total freezing UL SPACE CLUB

STELLAR CHRONICLE 54 . happens on land planets. The aqua planet, on the other hand, is completely frozen 90% of the time. As a result, a land planet has a higher resilience to total freezing. The tropics of a land planet are dry and characterised by absolute humidity on a physical level. As a result, the tropics of a land planet are less cloudy and less susceptible to snow fall than those of an aqua planet. As a result, the climate becomes warmer. Land planets are less humid than aqua planets and have lesser greenhouse effects. At the freezing point, however, this effect is negligible since the cold environment contains very little water vapour in any instance. Land planets, for example, have fewer clouds because they are less humid. The other reason is that land plants accumulate less snow than aqua planets. This is attributable not just to the drier environment, but also to the fact that daytime temperatures are higher due to low thermal inertia. Habitable planets are divided into four groups based on whether they are wet or dry, and whether their obliquity is high or low, as determined by some idealised tests. It is commonly known that the polar areas receive more insolation throughout the course of the year than the equator if the obliquity is high enough. Earth-like \"upright\" planets have different freezing limitations than high-obliquity planets. High-obliquity aqua planets are likewise more resistant to freezing than low-obliquity aqua planets. 2) Hot inner limit The commencement of the runaway greenhouse effect usually marks the inner border of the habitable zone. When there is enough water vapour in the atmosphere, the atmosphere becomes optically thick to thermal radiation, resulting in a runaway greenhouse. The saturation vapour pressure, temperature, and optical depth are all interrelated by the physical properties of water for an aqua planet.The temperature affects the saturation vapour pressure. As a result of the saturation limitation, the optical depth is a function of temperature. The greatest rate at which thermal radiation can be transmitted to space in the limit of an optically thick atmosphere is a fixed quantity known as the \"runaway greenhouse limit\" or \"critical flux\". The atmosphere heats up until nearly all of the water on the surface and in the atmosphere has evaporated, at which time the saturation vapour pressure no longer limits the temperature at which the planet may radiate, as in the traditional runaway greenhouse effect. The surface of the aqua planet would get extremely hot as a result of the large amount of water it holds, and the planet would be sterilised. UL SPACE CLUB

STELLAR CHRONICLE 55 . Conclusions: A pale blue dot isn't the only model for an Earth-like habitable planet. On our globe, there is an overabundance of water that ends up in the global ocean. Ice caps are examples of terrestrial cold traps. They do, however, have a limited capacity. On a land planet, however, atmospheric circulation regulates the distribution of available surface water. At high latitudes, water is trapped. As a result, a dry planet is resistant to both full freezing and runaway greenhouse. A thinner atmosphere would restrict energy flow from the equator to the poles, further stabilising the land planet against the runaway greenhouse effect. Topography is believed to improve the stability of cold traps, hence assisting in the stabilisation of the land planet. Nonzero obliquity, on the other hand, would make the polar traps less stable and thus the distinction between land and aqua planets would be reduced.An obliquity of zero is not necessarily unrealistic: in our own solar system, both Venus and Mercury have obliquities of zero. It's reasonable to assume that numerous planets in the inner edge of habitable zones, particularly those of small obliquities will be seen in stars colder than the Sun. The planet's continued habitability would not be in dispute if the change to a land planet was driven by geological processes (e.g., subduction of the oceans into the mantle). However, if the transition were made solely through hydrogen escape during a moist greenhouse phase, surface temperatures would rise significantly, putting the planet's continued habitability in jeopardy; a thinner atmosphere than today would help much. Venus has most likely evolved as a result of an out of control greenhouse effect. It's likely, but not certain, that early Venus possessed liquid-water oceans. It's plausible that Venus may have evolved into a habitable land planet if it had liquid water oceans. Venus could have remained habitable until as late as 1 billion years ago in this state. In conclusion, the habitable zone for land planets is far bigger than that of more traditional aqua planets. Moreover the habitable zone of the land planet is three times larger than that of the aqua world. 6. Closest known habitable exoplanets The search for habitable exoplanets and life outside our solar system is one of the most thrilling scientific opportunities of our time. Nonetheless, the high cost of building facilities to handle this topic, as well as the high public interest in the conclusions of such study, necessitate the thorough design of experiments that can yield a major gain in our understanding.At present, the majority of study in this discipline has focused on using a “systems science” approach to collecting and analysing large amounts of data for specific planets in order to make assertions about their habitability and potential for life. This UL SPACE CLUB

STELLAR CHRONICLE 56 . technique is challenging to apply because of the diversity of exoplanets, both observed and predicted, as well as the limited data that can be obtained using astronomical instruments. We can make use of a supplementary strategy based on conducting surveys of important planetary features and applying statistical marginalisation to answer bigger issues than a limited sample of objects can address. The primary idea of this comparative planetology technique is to get the most out of each sort of measurement by employing it widely instead of requiring many different types of observations on a single object. The abundances of water and carbon dioxide in the atmospheres of terrestrial exoplanets are a proof of concept that would test the habitable zone theory and lead to a better understanding of habitable planet frequency. Since the discovery of the first exoplanet orbiting a sunlike star in 1995, scientists have discovered over 4,000 more. NASA’s Kepler space observatory, which launched in 2009 with the goal of determining how frequent Earth-like planets are throughout the Milky Way galaxy, was responsible for more than half of these discoveries. Astronomers have long hoped to find the first true “alien Earth,” and recent exoplanet discoveries have revealed that small, rocky worlds like our own are prevalent throughout the cosmos. A planet must be small (and thus rocky) and orbit in the “habitable zone” of its star to qualify as potentially life-friendly. The “habitable zone” is loosely defined as a location where water can exist in liquid form on a planet’s surface.Other criteria, such as the planet’s atmospheric makeup and how active its parent star is, will be examined when telescope technology improves. While Earth 2.0 is still a mystery, here are some of the closest known analogues to our home planet. 1. Gliese 667cc 2. Kepler-22b 3. Kepler-69c 4. Kepler-62f 5. Kepler-186f 6. Kepler-442b 7. Kepler-452b 8. Kepler-1649 c 9. Proxima Centauri b 10.TRAPPIST-1e UL SPACE CLUB

STELLAR CHRONICLE 57 . 7. Settling in an Exoplnet_Pros and Cons Space colonisation is one of the exclusive domains of science fiction books and films, but with substantial improvements in rocket propulsion and design, astronautics and astrophysics, robotics, and medical, it is rapidly moving closer to becoming a reality. The advent of a worldwide pandemic, one of multiple reasons involving both natural and man-made calamities long championed in pro-colonization rhetoric, has re-validated the imperative to establish mankind as a multi-planet species. The long-term habitation of the International Space Station by rotating teams of astronauts, scientists, and medical professionals has provided us with a wealth of data that we can use to establish parameters for keeping humans alive and healthy in the harsh environment of space for long periods of time. Several major efforts on Earth have attempted to replicate as closely as possible the conditions of off-world habitation in order to test the limits of human endurance. To be sure, there are numerous daunting challenges facing future space colonists, including radiation protection, the impact on the human body from living and working in cramped, low-gravity environments for extended periods of time, and the psychological toll of isolation, confinement, and separation from one’s family and society. Advances in building design, alternative fuel production, 3D printing, and low-gravity environments could all be direct or incidental benefits to space colonisation. Humanity’s best hope for long-term survival is space colonisation. As a result, space colonisation is projected to have enormous moral value. Colonising space, on the other hand, entails dangers, risks whose potential harm may easily outweigh all the benefits of humanity’s long-term future. We have an obligation to eliminate space colonisation-related dangers and make space colonisation as safe as feasible, from a (weakly) negative, suffering-focused utilitarian perspective. To do so, we must begin developing real-world space colonisation governments. Given the near-total lack of development in space governance in recent decades, it is unclear whether real space colonisation governments can be developed in the near future, and before it is too late. When it comes to habitable exoplanets, the biggest disadvantage is their distance from Earth. For example, Proxima Centauri b (or Proxima b[4]) is an exoplanet in the habitable zone circling the red dwarf star Proxima Centauri, which is the closest star to the Sun. It is located in the constellation Centaurus, about 4.2 light years (1.3 parsec) from Earth, making it the nearest known exoplanet to the Solar System. That is, even if we move at the speed of light, it will take us 4.2 years to get there. Travelling at the current fastest spacecraft’s UL SPACE CLUB

STELLAR CHRONICLE 58 . speed – the Parker Solar Probe, which will reach 692,000 km/h (430,000 mph), or 0.064 percent the speed of light, by 2025 – would take more than 6,500 years. Even if that were conceivable, the journey would be one-way. There would be no way to coordinate a rescue in time if something went wrong on the route. Apart from the dangers of harmful radiation in space to which these space passengers would be exposed. Since they would be without the safety of a magnetic field, this high radiation could cause a slew of devastating ailments. As a result, we are still a long way off from having an Earth-like planet to which humans could one day go. Mars is a viable exploration option, and it already plays a significant part in research and advancements in this field.However, living there will be considerably different from ours – and likely quite tough. We must accelerate technological advancement if we are to colonise other planets without suffering. There have been numerous reasons presented in favour of and against space colonisation. The survival of human civilization and the biosphere in the case of a planetary-scale calamity (natural or man-made) and the availability of extra resources in space that could enable human society to expand are the two most prominent arguments in favour of colonisation. Concerns about the commodification of the cosmos enhancing the interests of the already powerful, including major economic and military institutions; enormous opportunity cost compared to expending the same resources here on Earth; exacerbation of pre-existing detrimental processes such as wars, economic inequality, and environmental degradation are among the most common objections to colonisation. There has yet to be established a space colony. A space colony would establish a precedent that would create a slew of sociopolitical issues. The simple development of the required infrastructure poses a slew of technological and financial obstacles. Space colonies are typically envisioned as organisational and material structures that must meet almost all (or all) of the demands of huge groups of people in an environment that is both hostile to human life and unavailable to maintenance and supply from Earth.It would entail technology that have yet to be created in any meaningful sense, such as controlled ecological life-support systems.It would also have to address the unknown problem of how humans would behave and flourish in such environments in the long run. A space colony would currently be a very expensive endeavour due to the existing cost of delivering anything from the Earth’s surface into orbit. There are currently no plans in place by any large-scale organisation, either government or private, to create space colonies. Many suggestions, predictions, and plans for space settlements have been UL SPACE CLUB

STELLAR CHRONICLE 59 . proposed over the years, and there are a significant number of space colonisation proponents and groups operating. 8. Conclusions and Future Studies The field of exoplanet research has been developing at an astonishing pace, ever since the first discovery of exoplanets around a solar-like star, 51 Peg (Meyer and Queloz 1995). In various detection techniques, the transit method provides the most robust instrument ever to measure the physical parameters of these intriguing hot Jupiters. Combined with the measurement of radial velocity of the host star, this planet may generate density, which may provide clues about the history of its formation. The discovery of new transiting planets by ground and space projects in the next few years will certainly increase our knowledge of these objects. We are beginning to be able to do comparative planetology, and new insights on the true mass distributions of these objects will be provided in the near future. The current situation has been compared by some authors to the state of stellar evolution knowledge just before the creation of the first HR diagram. With more than 150 exoplanets discovered to date, we are approaching the point in which statistical studies on these objects begin to be worthwhile. The future of exoplanet research: This is an exciting time for exoplanet research. With the continual increase in the number and types of exoplanets there is no doubt that there is much to learn and, as we move from the era of exoplanets to one-size-fits-all, all new research areas to improve upon. could. For example, in the case of our solar system, moons must be located near exoplanets, and these may provide lifelong habitats. The search for exomoons is on, but nothing has been found so far. Much of what we know about exoplanets – including extreme examples like potential diamonds and Earth lava – is still impressive technology that requires very detailed and precise measurements before anything can be verified. The CoRoT and Kepler space telescopes have revolutionised the field of exoplanets, and we can look forward to a thrilling era before the future of space technology. Based on what has been learned so far, these new systems are designed to detect minor planets orbiting bright stars. Since host stars illuminate a large number of discovered planets, this can be determined by radial velocity tests on grounded observations. Plato: ESA's PLATO (Planetary Transit and Starry Oscillation) policy is scheduled for launch in 2026. Plato is designed to detect and image a large number of extraterrestrial planets, searching for hundreds of thousands of bright UL SPACE CLUB

STELLAR CHRONICLE 60 . stars with ever-changing planets. Plato will have the unique ability to detect and determine the characteristics of the orbits of the planets around our solar system. Ariel: Going beyond the fundamentals of study and understanding, ESA's ARIEL (Atmospheric Remote-Sensing Infrared Exoplanet Large-Survey) campaign will chemically analyse a large, well-defined and diverse sample of exoplanets. For simultaneous detection between a range of visible and infrared waves, the goal would be to study exoplanets. Its launch date has been set for 2029. ARIEL is designed to perform high-speed motion, solar eclipse, and multiband phase-curve visualisation using simultaneous photometry in visible spectroscopy near infrared waves. It will observe and study a range of star species and planetary system structures, notably around 1000 volatile gases, Neptune and Super-Earth. 9. Bibliography and References 1. Introduction to exoplanets Sara Seager, Jack J Lissauer Exoplanets, ed. S. Seager, 3-13, 2010 2. Adapted excerpt from The Lost Planets: Peter van de Kamp and the Vanishing Exoplanets around Barnard’s Star by John Wenz, © 2019 3. Astrochemistry from Astronomy to Astrobiology by Andrew M. Shaw, John Wiley & Sons Ltd. 4. Yutaka Abe, Ayako Abe-Ouchi, Norman H Sleep, Kevin J Zahnle Astrobiology 11 (5), 443-460, 2011 5. jacob L Bean, Dorian S Abbot, Eliza M-R Kempton The Astrophysical Journal Letters 841 (2), L24, 2017 6. https://www.nasa.gov/ UL SPACE CLUB

STELLAR CHRONICLE 61 . Types of Stars MS Lalith Srivathsan, Student Member, UL Space Club When you look up the sky, at night, you would think that all the stars are same, but that’s far from the case, in fact there are a lot of different types of stars, From brown dwarfs to white supergiants this can be categorised according To their mass and temperature as in the hertzsprung Russell diagram. The main variable in star formation is mass and temperature; it is these which provide a wide variety of stars. 1. Red Dwarfs: Red dwarfs are small stars with temperature cooler than that of the sun, and the most common stars in our galaxy and less than half of the mass of sun and burn slowly and live longer and stay a long life relative to other types, and they are positioned under the hertzsprung Russell diagram. 2. Red giants: Red giants are cooler than the sun the sun so they have red orange tinge to the visible light they emit ,living up to their names a largest red giant may be over 100 times the size of a sun, red giant are stars near the end of their life they come above the main sequence on the hertzsprung russell diagram 3. Super giant: Stretching across the upper regions of the hertzsprung Russell diagram are the super giants , that cover a wide range of temperatures ,these stars are truly enormous ,placed in the centre of solar system the largest of these such as the red supergiant the betelgeuse in Orion ,would engulf all the planets out to the orbit of Saturn , like Betelgeuse Rigel in the UL SPACE CLUB

STELLAR CHRONICLE 62 . Orion constellation is also a super giant but it’s a blue white supergiant, supergiants are high mass stars the near the end the of their life, when a supergiant dies it explodes as a supernova then shrinks to become a black hole. 4. White dwarfs: There is a group of very faint stars in the bottom left layer hertzsprung Russell diagram, these are called white dwarfs , they are so faint that ,none is seen to the naked eye, they are small and dense, formed when a main sequence star reaches the end of its life , white dwarf stars gradually cools over time until no longer it emits light 5. Brown dwarfs: The smallest, dimmest and coolest stars are brown dwarfs. They are at the bottom of hertzsprung Russell diagram ,at the lowest part of the main sequence and also known as failed stars and difficult to detect, as the do not have sufficient mass for nuclear fusion to occur. UL SPACE CLUB

STELLAR CHRONICLE 63 . A brief introduction to Radio Astronomy Arya Sudhakaran & Sreya Sanjeev , Student Coordinators, UL Space Club 1. Introduction to Electromagnetic Radiation Electromagnetic radiation (EMR) consists of waves of the electromagnetic field, propagating through space, carrying electromagnetic radiant energy. Electromagnetic radiation consists of electromagnetic waves, which are synchronised oscillations of electric and magnetic fields. Electromagnetic waves are created due to periodic change of electric or magnetic field. Depending on this periodic change, different wavelengths of the electromagnetic spectrum are produced. In a vacuum, electromagnetic waves travel at the speed of light, c = 3× 108 m/s. The wavefront of electromagnetic waves emitted from a point source is a sphere. The position of an electromagnetic wave within the electromagnetic spectrum can be characterised by either its frequency of oscillation or its wavelength. Electromagnetic waves of different frequency are called by different names since they have different sources and effects on matter. In order of increasing frequency and decreasing wavelength these are: radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays. Electromagnetic waves are emitted by electrically charged particles undergoing acceleration, and these waves can subsequently interact with other charged particles, exerting force on them. EM waves carry energy, momentum and angular momentum away from their source particle and can impart those quantities to matter with which they interact. Although all electromagnetic waves travel at the same speed across space, they may differ in their wavelengths, frequencies, and energy levels. Wavelength is the distance between corresponding points of adjacent waves. The energy of electromagnetic waves depends on their frequency. Frequencies of electromagnetic waves range from thousands of waves per second to trillions of waves per second. Longer wavelength electromagnetic waves have lower frequencies, and shorter wavelength waves have higher frequencies. Visible light makes up just a small part of the full electromagnetic spectrum. Electromagnetic waves with shorter wavelengths and higher frequencies include ultraviolet light, X-rays, and gamma rays. Electromagnetic waves with longer UL SPACE CLUB

STELLAR CHRONICLE 64 . wavelengths and lower frequencies include infrared light, microwaves, and radio and television waves. Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum. Radio waves can be generated artificially by transmitters and received by radio receivers, using antennas. Radio waves are very widely used in modern technology for fixed and mobile radio communication, broadcasting, radar and radio navigation systems, communication satellites, wireless computer networks and many other applications. Radio signal strength would vary according to different parameters.we can improve radio signal strength using different types of reflectors. 2. Radio Signals and its Properties: Radio propagation is the behaviour of radio waves as they travel , from one point to another in vacuum, or into various parts of the atmosphere. As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarisation and scattering. In free space, all electromagnetic waves (radio, light, X-rays, etc.) obey the inverse square law, which states that the rate at which radio signal falls is proportional to the inverse of the square of the distance. Signal level = k / d² (1) Where, k is a constant, and d is the distance from transmitter In the case where there is a direct path between a transmitter and receiver. The receiver signal power, Pr is related to distance, d, by the inverse square law . Pr ∝ d-2 (2) However this is an ideal case for a point source. In the real world the signal often decays at a faster or slower rate. Pr ∝ d-n (3) Where n is the loss exponent. The exponent is altered to represent more accurately the real life scenario. In environments like the internals of buildings such as buildings, stadiums and other indoor environments, the path loss exponent can reach values in the range of 4 to 6. 3. Signal Attenuation UL SPACE CLUB

STELLAR CHRONICLE 65 . Attenuation is a general term that refers to any reduction in the strength of a signal. Attenuation occurs with any type of signal, whether digital or analog. Sometimes called loss, attenuation is a natural consequence of signal transmission over long distances. Free-space path loss (FSPL) is the loss in signal strength of an electromagnetic wave that would result from a line-of-sight path through free space, with no obstacles nearby to cause reflection or diffraction.The extent of attenuation is usually expressed in units called decibels (dBs). In the Free Space Path Loss(FSPL) model, the path loss results in the attenuation of signal propagation and can be calculated by the equation. FSPL(dB) = 10log Pt / Pr = −10log [ ������(������) ������(������)λ*λ ][dBm] (4π������)*(4π������) (4) where, G(t) : Antenna Gain of the transmitter G(r) : Antenna gain of the receiver λ : Signal wavelength d : Distance between Transmitter and Receiver The free space propagation model is the simplest scenario for the propagation of radio signals. Here they are considered to travel outwards from the point where they are radiated by the antenna.Free space propagation model gives the condition where there is no interference in line-of-sight path between the transmitter and receiver. In the free space model, relation between RSSI and distance is described as Pr = Pt Gt Gr λ 2 (4πd)2 (4) where, Pr : Received power Pt : Transmitted power Gt =1, Gr = 1 Because, when antenna gains are excluded, the antennas are assumed to have unity gain. It is normally more convenient to be able to express the path loss in terms of a direct loss in decibels. In this way it is possible to calculate elements including the expected signal, etc. P(dBm) = 10 log10 P = Pt (dBm) + 20 log10 (λ) - 20 log10 4π - 20 log10d (5) UL SPACE CLUB

STELLAR CHRONICLE 66 . P(dBm) = Pt (dBm) - 20 log10 (4πd)/������ (6) Wavelength of radio frequency carrier, ������ = ������ ������ where, c = 3 × 108 [ms-1 ] f = 2.4[GHz] (7) Over a distance d the relationship between Pt & Pr is given by Pr = Pt ������2/(4πd)2 4. Reflectors Electromagnetic radiation is used for communications and transmission of information. Radio communication through cell phones, television etc utilises the propagating behaviour of EM waves which travel with the velocity of light. These waves carry energy and momentum. Reflectors play an essential role in Radio communications. Different types of reflectors are used for different applications. Some of them are plane reflectors, spherical reflectors, corner reflectors, etc. In our experiment, a plane reflector made of aluminium foil is placed behind the antenna. When integrated into an antenna, the reflector modifies the radiation pattern, thus increasing gain in a given direction. Thus the reflectors increase directionality. 4.1. Back Reflector A metal sheet placed at the back of the radiator serves as a simple back reflector. Any readily available metallic plate, preferably larger than the antenna can be used as the back reflector. If a metal plate is not available, we can use cardboard with an aluminium foil covered on it. A conducting Substance is placed in the path of the wave it will reflect. If the reflector is perpendicular to the wave then it travels in the same path but opposite direction. This forms an interference pattern. The amplitude of the radiant wave depends on the relative phase shift. ● When we place a reflector behind the antenna, there is an increase in the signal strength due to an increase in directionality. ● Reflectors consist of one or more reflecting surfaces and a feed system for transmitting and receiving electromagnetic waves. ● Reflectors can exist as a standalone device for redirecting radiofrequency energy or can be integrated as part of an antenna assembly. Dimensions of the UL SPACE CLUB

STELLAR CHRONICLE 67 . reflector can directly influence the performance of an antenna with an integrated reflector. ● Aluminium cans and aluminium foil can be used effectively to boost wireless signals in the home. Aluminium foil serves by blocking the signal from going in one direction and concentrating it in the other direction. This increases their range and also their strength. Radio waves propagating through a medium usually interact with the transmitting medium such as dielectric medium i.e. buildings, ground, and other components of the environment resulting in different phenomena. Reflections from the earth’s surface, the ionosphere, natural or man-made objects, and atmospheric refraction can create multiple paths between the transmitting and receiving antennas. Depending on the relative path distance, the reflected wave is shifted in phase to the original wave, which can cause interference at the receiver called multipath (Scattering of radio waves eventually leads to the creation of multiple copies reaching the receiver. ) interference. 4.2 Corner Reflector: A type of reflector consisting of either two or three flat sheets that are conductive, intersecting at 90° forming a corner, that allows the reflection of incoming waves is known as a Corner Reflector. The type of reflecting sheets that form corners offers high directive gain thus highly facilitating its use in antenna systems. Principle of Corner Reflector: The principle of Corner Reflector is that when an electromagnetic wave strikes the corner reflector then the incoming ray gets reflected from each electrically conductive surface once. A corner reflector UL SPACE CLUB

STELLAR CHRONICLE 68 . with a trihedral structure reflects the signal thrice. Corner reflectors confine radiated energy of signals within the metallic plate and this will improve the directivity by reflecting confined energy in the desired direction. It is a passive device used to directly reflect radio waves toward the emission source. Therefore, the corner reflector is a useful device for radar system calibration. The Corner Reflector-Antenna: A beam antenna called the corner, V, or sphenoidal reflector type is described and designed/constructed for the experiment. This antenna consists essentially of a driven radiator or dipole and a reflector constructed of two flat, conducting sheets, or their electrical equivalent, which meet at an angle forming a corner. The radiator is usually located in the plane bisecting the corner angle. Figure:1 shows the diagram of a sample corner reflector. All these reflectors help to improve the directionality of emitted radio signals and thus its strength.That is why reflectors are an integral part of the radio telescopes. Spherical reflectors are most widely used,because it can reflect maximum amount of incident radiation in the opposite direction of incident signal but in the same plane and Of the reflectors discussed above, the corner reflector gives the highest signal strength, each surface of reflector will reflect incident signal once and produce maximum signal strength,followed by back reflector.Reflectors plays a major role in improving the directionality of signals and thus producing maximum signal strength.Understanding the appropriate use of various reflectors are important in radio astronomy studies. UL SPACE CLUB

STELLAR CHRONICLE 69 . Diary Of My Weird Dreams! Aneena A, member , Cosmos Group 10 Feb 2020 Today I woke up at 2 in the morning. The Halcion is not working properly on my sleeping pills. I think I should change my sleeping pills. I am going to read something now. Moreover, I didn't get any sleep. Let's read Dark matter. 11 March 2020 Good morning my diary. oh! I had a great night. Changing my pill was a great idea. I should keep on this Restoril sleeping pill. It helps me to fall asleep faster than before. Today will be a great working day. 18 April 2020 It started a few days ago, the dream that... I don't know how to explain it. I was seeing myself in my dream and the room looked the same but with some differences. In my dream I was sleeping on the sofa..my face was a bit swollen or is that fat. After waking up I felt like throwing up, my head was spinning and a few moments later everything got back to normal. UL SPACE CLUB

STELLAR CHRONICLE 70 . 19 April 2020 I discussed this with my friend, she is a doctor. She says that I should stop consuming this sleeping pill, and this sleeping pill gives me weird dreams and nausea. But it is difficult for me to stop using this pill. Because I love falling asleep. But the problem is that dream. 20 April 2020 2 a.m : Oh shit! It is 2 in the morning. I should take that pill 8 Am : Oh no, that dream. I was somewhere else. Standing beside a river. I was wearing a mask and the river looked like it was filled with dark oil. When I turn back there is a board written [ wear mask: RADIOACTIVE AREA]. That time I realised this place contained radioactive waste and that is dangerous..but that place looks familiar. Oo shit ..now I know that that is the place where I am now my home 28 April 2020 Inside my dream: In this dream I look a bit different. The person in this dream who looked exactly like me has long hair, but I like short hair. I am getting ready to go somewhere. When I just open the door. I saw a different city, I can't even say that is the same place I am living now. (Let's call the person the same as me in every dream as the other me) Now the other me is taking a toy car from the bag and walking towards the road and placing it. Then she switches something. Suddenly the car gets big and all functioning (same as in the movie Any man). If that was mind-blowing but it was just a dream 30 April 2020 In today's dream, I saw some different things. I saw a place that was fully covered with trees and plants. I was searching for the other me and I saw she was sitting on the top branch of the tree. She was thin and did not have that much dress and had long hair to cover her entire body. She was tired of looking somewhere beyond the trees. I climbed the tree and I can do anything when I am in my dream. hehehe... I sit beside her and look. OMG what beautiful scenery UL SPACE CLUB

STELLAR CHRONICLE 71 . and I never saw something this beautiful before the horizon, the trees look like bushes, the rainbow.. Everything is so perfect and beautiful. I turn back and the sun is slowly rising. But I fell From tree and I wake up 1 May 2020 Today I saw something different. The other me has a boyfriend and he is so.. handsome, suddenly I fainted and woke up. I just missed it .Why should I faint? if I didn't ...oo shit..whyyyyy. 3 May 2020 I saw the other me was sitting on the corner and writing something .She looked like she didn't eat or drink for a few days..and the room was a real mess. she was shaking her legs while writing and biting her nails, her face looked like she was suspecting something. Suddenly she pulls her chair with joy when she finds something. I walk towards her and I just go through her book . Oo God it was full of equations and scripts. But the last word that locked my eyes was MULTIVERSE. She wrote that the multiverse exists. and I suddenly woke up from my dream. Yes, Now I get it I was dreaming every day in each universe. I am not the only one living in this world. There is not only one universe exit. There is an aam multi-universe. and also a different version of me living on different types of the earth in different conditions. That's why every dream looks different, one was in a radioactive place, the other was me in a technologically developed place. Each dream is each universe and how I saw all of it. 4 May 2020 Ok! I concluded all of these. This dream started when I started to take the Restoril pill. This pill somehow triggers my brain. How about my brain passing a signal. when it is full of stored energies. How about the westoril pill charging my brain and the signal is the same as a binary number that carries the signal in one's and zero's or How about my brain and the other me's brain are connected somehow. I don't know. How about this is all because the brain gives weird thoughts and dreams. Anyway, the multiverse is true and exists { Inspired by Dark matter by Blake crouch and also from sci-fi movies} UL SPACE CLUB

STELLAR CHRONICLE 72 . Are we Alone in this Universe, or are there any Aliens? Krishnendu T N, Student Member, UL Space Club This is one of the important questions in space science which we didn't get any appropriate answers till now. It is to spread the importance of UFOs and to promote sky watches for finding UFOs. July 2nd is celebrated as UFO day. The day is celebrated by some on 24th June and others on 2nd July.On 24th June aviator Kenneth Arnold reported nine unidentified flying object sightings.This is considered to be the first widely reported unidentified flying object sightings.He said that he saw a string of 9 UFO flying in the sky.On 2nd July the Roswell incident was happened,the crash of a US army Air forces balloon at a ranch near Rosewell.With that so many conspiracy theories were made and it was clarified by the US government that the crashed object was a conventional weather balloon. Till now, so many studies on UFOs were conducted.It began in UL SPACE CLUB

STELLAR CHRONICLE 73 . 1940s.Mainly there was three projects for investigation.They are project garud,project sign and project Blue book.In the summary of the project Blue book,the Air force stated that \"there were no evidence for the sightings categorised as unidentified were extra terrestrial vehicles it may be natural phenomena\".The project ended on 17th December 1969 and it was the base of several fiction stories and films on ET lives and UFO,which spread the idea of UFO among the public. UFO sightings were also reported in various parts of India.On 1951 members of a flying club had reported sightings of UFO.They described it as a 'Cigar' shaped object.From 2013,there were so many such reports.It was commonly from the region in Chennai and Lucknow.On 4th August 2013 Indian army soldiers had reported a UFO sightings in Ladakh. Recently pentagon have submitted a UFO report to the US government which was published on 25th June of 2021.They have analysed 144 identified objects sightings from 2004 to 2021.They couldn't identify 143 of 144.Only one among them was identified and it was a large deflating balloon. Most of the aliens conspiracy theories were concentrated on Area 51 which is situated near the groom lake,a dry Lake in Nevada desert.It was created during the cold war for testing and developing aircrafts.Many people believe that there are aliens dead body and their vehicles in Area 51 and they are making conversations with aliens but the US government didn't accept that. To know the truth we should watch the sky. The whole world is trying to find UFOs,so let's join them!. UL SPACE CLUB

STELLAR CHRONICLE 74 . Scope of Sounding Rockets in plasma related Researches Manasa K Krishnan, Student Member, UL Space Club 1. Introduction: A sounding rocket payload developed for studies of high-temperature plasmas associated with solar active regions and flares. The payload instruments will record both spectra and images in the UV, EUV, and soft X-ray regions of the spectrum. The instruments, including the Dual Range Spectrograph, the Flat Field Soft X-ray Spectrograph, the Normal Incidence Soft X-ray Imager, the UV Filtergraph, and the H-alpha Imaging system, are described. Attention is also given to the new structural system of the payload, based on a large optical table suspended within the payload cavity, which will support the optical elements in their correct positions and orientations and will maintain these alignments throughout the rocket launch environment. 2. Sounding rocket for solar corona studies Eg: 1) Nasa's MaGIXS (Marshall Grazing Incidence X-ray Spectrometer) Scientists think that the mechanism that heats the corona is related to dramatic outbursts of light and plasma that scientists call solar flares and coronal mass UL SPACE CLUB

STELLAR CHRONICLE 75 . ejections. (These outbursts can strike Earth or spacecraft and wreak havoc on electronics, so MaGIXS and other research on these processes could make future spaceflight safer.). MaGIXS consisted of a telescope, a high-powered camera and an X-ray spectrometer.That last instrument observed what scientists call \"soft\" X-rays, like those doctors use in medical scans.Even though these soft X-rays carry comparatively less energy, observing them could still reveal what's happening inside the sun. And specifically, the scientists behind MaGIXS hope that these X-rays — and the mission's ability to map them and their temperatures to specific solar regions — will provide evidence of either sporadic or constant heating in the corona. 2)FOXS I (Focusing Optics X-ray Solar Imager, or FOXSI) The Focusing Optics X-ray Solar Imager, or FOXSI, is a sounding rocket payload built by UC Berkeley and led by Säm Krucker to test high energy grazing-incidence focusing optics paired with solid-state pixelated detectors to observe the Sun. FOXSI is composed of seven identical Wolter-I telescope modules, as well as Silicon and Cadmium Telluride strip detectors originally developed for the HXT telescope on the Japanese Hitomi mission. The FOXSI payload flew two times, most recently in 2014 and previously in 2012. Like most sounding rockets, FOXSI flew for approximately 15 minutes per mission and observed the Sun for about 5 minutes while in space. During its first flight, FOXSI successfully imaged a solar microflare in the hard x-ray band for the first time. FOXSI's third mission, led by Lindsay Glesener of the University of Minnesota, had a successful launch on September 7, 2018 from White Sands, New Mexico. This iteration of the payload included a combination of Silicon and improved Cadmium Telluride detectors, as well as one configuration, and the payload also introduced collimator technology to reduce the impact of singly-reflected rays. Figure :A high resolution render of the FOXSI-2 payload. UL SPACE CLUB

STELLAR CHRONICLE 76 . 3. Sounding rocket for Solar flare studies 3.1 Hi c flare Quote of a scientist related to mission: Understanding how the Sun works is important to everyday things we do on Earth,” said Winebarger. “Solar flares and eruptions can disrupt radio, GPS communications and satellites that disseminate cell phone signals. By studying how the Sun releases these bursts of energy, we hope to be able to better anticipate them and, in the future, design technology better equipped to withstand these disruptions. Source : NASA-Marshall Space Flight Centre 4. Sounding rocket for Aurora studies 4.1 Nasa's KiNET-X (aimed to investigate the transport of momentum and energy between magnetically connected regions of space in the context of space plasmas.) KiNET-X consists of a single rocket launch carrying seven separable payloads — diagnostic instrumentation the main, alongside four small sub payloads, and barium vapour clouds set to release from two additional, larger sub payloads. UL SPACE CLUB

STELLAR CHRONICLE 77 . Two vapour clouds emitted from the rocket’s payload will generate a magnetic field perturbation,and electrons are likely to be energised, according to NASA's breakdown. 5. Sounding rocket for sun's magnetic field studies 5.1 Nasa's Clasp-2.1(Chromospheric Layer Spectropolarimeter 2.1,) Aims to measure the magnetic field in a critical slice of the sun's atmosphere called the chromosphere. Quote of a scientist related to this project; By understanding the magnetic field in the sun, we can learn to predict when these events are going to happen,\" McKenzie said. One day, the information could help scientists warn energy companies about high-risk events or tell astronauts when it's safe to do a spacewalk. Reference 1. ui.adsabs.harvard 2. www.space.com 3. www.nature.com 4. agup ubs.online library 5. baas.aas.org/pub 6. phys.org/news 7. www.spaceref.com UL SPACE CLUB

STELLAR CHRONICLE 78 . The Airglow and Electroglow of Outer Planets Abhiram T P, UL Space Club member What is airglow? Airglow is the emission by a planet’s atmosphere. This phenomenon originates with self illuminated gases and it has no relationship with Earth's magnetism and sun spot activity. This was firstly identified by a Swedish scientist Anders Jonas Ångström in 1868. Various chemical reactions have been observed to emit electromagnetic energy as part of the process. Airglow is caused by various processes in the upper atmosphere of Earth, such as the recombination of atoms which were photoionized by the Sun during the day, luminescence caused by cosmic rays striking the upper atmosphere, and chemiluminescence caused mainly by oxygen and nitrogen reacting with hydroxyl free radicals at heights of a few hundred kilometres. Airglow of outer planets MARS Unlike Earth’s oxygen-rich atmosphere, Mars is composed mostly of carbon dioxide (CO2). Mars’ glow occurs from a breakdown in these CO2 molecules. The resulting oxygen atoms glowing in both visible and ultraviolet light. Trace Gas Orbiter of ESA VENUS The night airglow spectrum of Venus in the ultraviolet is dominated by the v′= 0 progressions of the gamma and delta bands of nitric oxide. The bands are produced by two-body radiative recombination of nitrogen and oxygen atoms. UL SPACE CLUB

STELLAR CHRONICLE 79 . Since the source of these atoms is in the dayside thermosphere, the night airglow is a tracer of the day-to-night thermospheric circulation. The airglow is brightest at equatorial latitudes, and at longitudes on the morning side of the antisolar meridian. JUPITER Observations of Jupiter's nightside airglow (nightglow) and aurora obtained during the flyby of the New Horizons spacecraft show an unexpected lack of ultraviolet nightglow emissions, in contrast to the case during the Voyager flybys in 1979. The flux and average energy of precipitating electrons generally decrease with increasing local time across the nightside,consistent with a possible source region along the dusk flank of Jupiter's magnetosphere. Visible emissions associated with the interaction of Jupiter and its satellite Io extend to a surprisingly high altitude, indicating localised low-energy electron precipitation. These results indicate that the interaction between Jupiter's upper atmosphere and near-space environment is variable and poorly understood; extensive observations of the day side are no guide to what goes on at night. Previous missions ● Ionospheric connection explorer ● Global-scale observations of the limb and disk ● Thermosphere Ionosphere Mesosphere Energetics and Dynamics NOT A SIMPLE ONE This is an experiment which needs very high technical finishing, funding, and instruments, this will get the preference place near the bottom of the table. It has its own complexities in the experiment mechanism. Resources 1. https://en.wikipedia.org/wiki/Airglow 2. https://www.britannica.com/science/airglow 3. https://www.albany.edu/faculty/rgk/atm101/airglow.htm 4. https://www.smithsonianmag.com/smart-news/green-glow-detected-mars- atmosphere-180975113/ 5. https://sci.esa.int/web/venus-express/-/47935-oxygen-airglow UL SPACE CLUB

STELLAR CHRONICLE 80 . Ionospheric Studies Varun K & Aswathi O.T , Student Member, UL Space Club Figure: Ionospheric Layers Ionospheric Electron Density (IED) ● The ionosphere exists between about 90 and 1000 km above the earth’s surface. ● Radiation from the sun ionises atoms and molecules here, liberating electrons from molecules and creating a space of free electrons and ions. Studying IED ● The ionospheric variability is greatly influenced by both solar-originated processes and the neutral atmosphere origin. UL SPACE CLUB

STELLAR CHRONICLE 81 . ● Scientists have tried to model the ionosphere using theoretical and empirical techniques; however, the accurate prediction of electron density is still a challenging task. ● In recent years, Artificial Neural Networks (ANNs) are showing the potential to handle more complex and non-linear problems Significance of IED ● Due to the ability of ionised atmospheric gases to refract high frequency (HF, or shortwave) radio waves,the ionosphere can reflect radio waves directed into the sky back toward the Earth. ● Radio waves directed at an angle into the sky can return to Earth beyond the horizon. ● This technique, called “skip” or “skywave” propagation, has been used since the 1920s to communicate at international or intercontinental distances. Langmuir probe A Langmuir probe is a device used to determine the electron temperature, electron density, and electric potential of a plasma. It works by inserting one or more electrodes into a plasma, with a constant or time-varying electric potential between the various electrodes or between them and the surrounding vessel. The Langmuir probe has been a standard tool for measuring the electron energy distribution in plasma for decades. They work by measuring the current response of a small metal electrode placed in the plasma and biassed with a swept voltage. Inserting an electrode directly into the plasma introduces a possible source of contamination. At intermediate bias voltages, the number of electrons (and thus the recorded current) that can overcome the bias potential depends upon the energy distribution. UL SPACE CLUB

STELLAR CHRONICLE 82 . A brief study on Plasma Bubble Aswathi O T, Manasa K Krishn, Student Member, UL Space Club What is a plasma bubble? ● Equatorial plasma bubbles are an ionospheric phenomenon near the Earth’s geomagnetic equator at night time. ● The plasma irregularities have been frequently observed in the F-region, at low latitude regions, due to the instability processes occurring in the ionosphere. Formation of Plasma Bubble ● Plasma bubbles form after dark when the sun stops ionising the ionosphere. ● The ions recombine, forming a lower density layer. This layer can rise through the more ionised layers above via convection, which makes a plasma bubble. ● The depletions in electron density, as compared to the background density, is a signature of the plasma irregularities. These irregularities are also known as the “equatorial plasma bubble” (EPB). UL SPACE CLUB

STELLAR CHRONICLE 83 . Detection ● These EPBs can be measured by the total electron content (TEC) using a GPS receiver and by images of the nightglow OI 630.0 nm emissions using an all-sky imager (ASI). Nightglow emission OI 630.0 nm measurement ● Nightglow OI 630.0 nm emissions are generated at low latitude F-region heights (250–300km). ● The nightglow emission in F-region at (1D) 630.0 nm is governed by dissociative recombination between ions and electrons. ● The nightglow OI 630.0 nm images are used to study the characteristics of EPBs. ● ASI (all sky imager) is an important aide towards improving the understanding of the coupling between ionosphere and thermosphere using images of nightglow OI 630.0 nm emission and OH emission. Because OH emissions are generated at around 100 km (ionosphere) while OI 630.0 nm emissions are generated at around 250km(thermosphere). TEC MEASUREMENTS ● The ionosphere has an effect on the signal of GPS satellites. TEC is measured along the path from the GPS satellite to a receiver. ● The TEC is defined by the integral of electron density in the TEC unit (TECU), where 1 TEC unit = 1016 electrons / m 2column along the signal transmission path. ● The dual-frequency GPS receivers are used to measure the TEC, which is one of the most important methods to investigate the dynamics of the ionosphere. UL SPACE CLUB

STELLAR CHRONICLE 84 . ● The slant TEC is the measure of the total number of free electrons in a column of the unit cross-section along the path of the electromagnetic wave between the satellite and the receiver. ● Hyderabad (17.37°N, 78.48°E) is a unique station to study ionospheric irregularities because it is located at the northern crest of the equatorial ionisation anomaly. ● A dual-frequency GPS receiver can measure the difference in ionospheric delays between the L1 and L2 of the GPS frequencies, which are generally assumed to travel along the same path through the ionosphere. ● We can measure TEC through the Equation ● TEC = (1÷40.3) × c × [(f^2L1 × f^2L2) ÷( fL12 − fL22 ) ]× ∆(δt) ● Here, ∆(δt) is a time delay in the pseudo-range (δtL1) at L1 and pseudo-range (δtL1) at L2. ● Where fL1 and fL2 are the group path lengths corresponding to the high and low GPS frequencies. ● “ c ” is the speed of light in a vacuum. UL SPACE CLUB

STELLAR CHRONICLE 85 . Challenges to equatorial plasma bubble ● They affect radio waves by causing varying delays. ● They degrade the performance of GPS. ● Equatorial plasma bubbles (EPBs) can cause rapid fluctuations in amplitude and phase of radio Signals traversing the ionosphere and in turn produce serious ionospheric scintillations and disrupt satellite-based communication links. ● It will cause problems in the landing of flights. UL SPACE CLUB

A Glance through ‘22 Events.. UL SPACE CLUB

STELLAR CHRONICLE 87 JANUARY 1. January 6 - American aerospace company SpaceX launched its first Falcon 9 rocket of the year 2022, on January 6 from NASA's Kennedy Space Centre in Florida. The Falcon 9 rocket carries a stack of 49 Starlink satellites. 2. January 24 - NASA’s James Webb Space Telescope reached its final destination - Lagrange point, or L2, on 24th January. James Webb Telescope, the most complex telescope ever built, has been heading towards L2 since its launch on 25 th December. UL SPACE CLUB

STELLAR CHRONICLE 88 FEBRUARY 1. February 18 - NASA's perseverance team celebrates the one year anniversary of landing on February 18. In search for signs of ancient life, NASA had launched the rover to Mars on 30 th July 2020. \"I've been on Mars for an Earth year, and I'm learning so much about this planet. Watch the live event on my landing anniversary and ask members of my team questions about our mission\", the Perseverance rover's mission team tweeted. APRIL 1. April 8 - On 8 th April 2022, SpaceX and Axiom Space made history by sending the first ever private crew to ISS, by Axiom 1 mission. The mission, which launched on a SpaceX Falcon 9 rocket and Crew Dragon spacecraft, carried four private astronauts. UL SPACE CLUB

STELLAR CHRONICLE 89 2. April 27- The space-X crew 4 mission took four astronomers to explore the space. MAY 1. May 12- First ever image of Sagittarius A,the blackhole at the centre of the Milky way galaxy was captured by the Event Horizon telescope.Sagittarius A* is a supermassive blackhole and is 25,640 light years away from the Earth.This is the second picture of a blackhole.The first picture is of the blackhole at the centre of M87 galaxy obtained using Event Horizon telescope. Source: EH Telescope 2. May 15, 16 - Total lunar eclipse.Lunar eclipse occurs when the Sun,the Earth and the moon come in a straight line and the moon comes in the Earth’s shadow.A total lunar eclipse occurs when the moon is completely in the darkest part of the shadow of the Earth.A total lunar eclipse is on May 15-16. UL SPACE CLUB

STELLAR CHRONICLE 90 Through the Stunning Clicks from, members, ‘SKY SAFARI’…. (Theme for Photography: “The Night Sky”) UL SPACE CLUB

STELLAR CHRONICLE 91 Photographs taken by Prithvi S Hari UL SPACE CLUB

STELLAR CHRONICLE 92 Photographs taken by Nandana P UL SPACE CLUB

STELLAR CHRONICLE 93 Photographs taken by Arya Sudhakaran UL SPACE CLUB

STELLAR CHRONICLE 94 Photograph taken by Amin hasan Photograph taken by Krishna UL SPACE CLUB

STELLAR CHRONICLE 95 A Glance through the beautiful paintings from… members, ‘UL SPACE CLUB’… (Theme for Painting:“The Creative Space”) UL SPACE CLUB

STELLAR CHRONICLE 96 Art by Nanda Suresh M.K. UL SPACE CLUB

Art by Souparnika Saja UL SPACE CLUB

(Back Cover Page) NASA’s Event Horizon Telescope (EHT) captured the first ever image of the supermassive black hole at the centre of our galaxy. The imaging of the supermassive black hole, named Sagittarius A* (Sgr A*), provides strong evidence to support the 60-year-old theory that a supermassive black hole lurks at the centre of the Milky Way. UL SPACE CLUB IS PROMOTED AND NURTURED UNDER THE UMBRELLA OF ULCCS Ltd (Uralungal Labour Contract Co - Operative Society) UL SPACE CLUB

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