Astronomy & Space Technology

Context: Space travel poses significant challenges to human health due to microgravity, radiation exposure, and psychological stress.

Relevance of the Topic: Prelims & Mains: Impacts of space travel on the health of an astronaut. 

Space omics

• Space omics is a set of studies to understand how the space environment can impact the human body. 
• Factors in Space impacting Astronauts: 
  • Radiation exposure (Unlike earth’s magnetic field that shields from space radiation, astronauts are exposed to high-energy radiation permeating the cosmos).
  • Microgravity (Without gravity bodily fluids shift upward and thus increase intracranial pressure)
  • Confined environments (Isolation and limited social interaction and exposure to natural stimuli)
  • Time (Symptoms become more pronounced with increased stay duration in space). 

Impacts of Space Travel on the Health of an Astronaut: 

1. Bone and Muscle Degeneration: 

• Bone Weakening:
  • Microgravity results in the weakening of bones (particularly those that bear the body's weight on Earth). 
  • The bone density loss occurs at a rate of about 1-2% per month, increasing the risk of fractures and osteoporosis.
• Muscle Atrophy:
  • Muscles in space experience reduced demand which leads to loss of muscle mass and strength. 
  • E.g., weightlessness in space reduces the heart's workload, leading to shrinkage of heart muscles. The cardiovascular system struggles to regulate blood pressure upon return to Earth.
• Balance and Coordination Issues: Prolonged exposure to microgravity conditions also affects the inner ear’s ability to sense movement and orientation, leading to balance and coordination issues.
• RBC Loss: Blood loses more red blood cells per day in space than on Earth. This condition is called space anaemia.

2. Spaceflight-Associated Neuro-Ocular Syndrome (SANS):

•  In microgravity conditions, the fluids in the body shits upwards towards the head. This leads to an accumulation of fluid at the back of the eye resulting in facial swelling and vision loss.
• Around 70% of astronauts involved in long-duration spaceflight develop SANS. 

3. Changes in Gene Expression:

• NASA's Twins Study (2016) revealed that space travel causes an increase in DNA methylation and the process of turning genes on and off (gene expression). 
• Space travel caused lasting changes to 7% of the genes of astronaut Scott Kelly compared his DNA to that of his twin brother. 
• High radiation exposure can lead to DNA damage, increased cancer risk, neurodegenerative effects and immune system dysregulation.

4.  Psychological Stress:

Long-duration space missions can lead to psychological stress, sleep disturbances, and mood disorders.

Also Read: Gopi Thotakura to be the first Indian space tourist 

Context: Indian Researchers have created the first ever detailed geological map of the moon’s south polar region, where India’s Chandrayaan-3 lunar module (Vikram) landed on August 23, 2023. 

Relevance of the Topic: Prelims: Key facts about Chandrayaan mission series. 

Major Highlights:

• Researchers from the Physical Research Laboratory (Ahmedabad), Panjab University (Chandigarh), and ISRO’s Laboratory for Electro-Optics Systems have created the lunar map using data from the Pragyan rover. 
• The new map shows an undulating landscape of highlands and low, flat plains around the landing site. 
• Using the map, the age of the region is calculated to be around 3.7 billion years.  It is around the same time the first signs of microbial life emerged on Earth. 
• Researchers traced the alignment of secondary craters and identified Schomberger crater as the primary source of debris covering the landing site. 

Significance

• Understanding Lunar Evolution:
  • The map will throw new light on the moon’s origin and geological evolution.
  • Lunar craters are important tools for scientists to calculate the age of geological features on other planets with solid surfaces. 
  • This can give significant insights about the evolution of impact craters elsewhere on the earth and on the inner planets of the solar system.

Confirms magma hypothesis

• Data from previous missions (Apollo, Surveyor, Luna, Chang’e 3 probes), indicated the presence of sea of lava beneath the lunar surface, but lacked data from polar regions. 
• Pragyan’s Alpha Particle X-ray Spectrometer detected magma under the landing site (near the Polar region). This confirms the ancient ocean of molten lava once extended across the entire moon.

Also Read: Chandrayaan-4 Mission 

Context: NASA’s James Webb Space Telescope is providing insights into the chaotic events unfolding around the supermassive black hole Sagittarius (Sgr) A*, at the center of our Milky Way galaxy.

Relevance of the Topic: Prelims: Sagittarius (Sgr) A*; Terms associated with black holes; James Webb Space Telescope. 

Major Highlights:

• James Webb has allowed astronomers to observe the region around the black hole Sagittarius (Sgr) A*, for extended periods for the first time.
  • The region around Sgr A* was seen active, rather than remaining in a steady state. 
  • A constant flickering of light from its accretion disk (swirling disk of gas surrounding the black hole) and occasional bright flares were observed. 
• Significance: The observations are providing insight into how black holes interact with their surrounding environments. 

About Sagittarius A*

• Sagittarius (Sgr) A* is the supermassive black hole at the Galactic Center of the Milky Way.
  • Supermassive black holes are found at the centres of most galaxies including the Milky Way. 
  • Their origin is not exactly understood, but may involve accretion of matter, merger or collapse of massive gas clouds. 
  • Their masses range from millions to billions of times the sun’s mass.

• Sgr A* possesses roughly four-million-times the mass of our sun and is located about 26,000 light years from the Earth.
• Sgr A* is a bright and very compact astronomical radio source. It is not as active as some at the centres of other galaxies.

What are Black Holes?

• Black holes are the regions of spacetime where gravity is so strong that nothing (including light and other electromagnetic waves) has enough energy to escape. The boundary of no escape is called the event horizon. 
• Formation: A black hole forms when a massive star (at least three times the mass of our Sun), exhausts its fuel, explodes in a supernova, and collapses under gravity into an incredibly dense core called a singularity.

Key terms related to black holes

S.No.	Terms	Description
1.	Singularity	- The centre of a black hole is a gravitational singularity. It is a point where the predictions of general theory of relativity do not apply.
2.	Accretion Disc	- Accretion disc is a flat, rotating structure of matter (gas, dust, or other material) that forms around a black hole. The material in the accretion disc spirals inwards due to the gravitational attraction of the black hole.  - As the matter spirals inward, it gets heated up due to friction and emits various forms of electromagnetic radiation (including visible light, X-rays, gamma rays and radio waves).  - About 90% of the accretion disk’s material falls into the black hole, while the rest is ejected back into space.
3.	Event Horizon (a point of no return)	- The event horizon is like a boundary around a black hole (around the singularity).  - Once anything (matter, energy, light) crosses this boundary, it can not escape unless it travels faster than the speed of light (which is impossible).
4.	Ergosphere	- The Ergosphere is a bigger sphere, outside the event horizon of a black hole, where matter can enter and then return (escape the black hole's gravitational pull), if they are moving with speeds very close to the speed of light.

About James Webb Space Telescope (JWST)

• World’s most advanced telescope launched in 2021 designed to conduct infrared astronomy. 
• It is the largest infrared telescope ever built (6.5 metre primary mirror). It detects near-infrared and mid-infrared wavelengths to observe faint and distant objects.
• Location: Orbits the Sun at L2 Lagrange point (1.5 million km from Earth)
• It is equipped with high-resolution and high-sensitivity instruments, enabling investigations such as:
  • observation of the first stars and the formation of the first galaxies (almost to the beginning of the universe. 
  • detailed atmospheric characterisation of potentially habitable exoplanets. 
• JWST can see further than Hubble Telescope and is considered as its successor. 
• Collaborative Project of: National Aeronautics and Space Administration, European Space Agency and Canadian Space Agency.

Context: A combined research of Institute of Science Tokyo and Paris Institute of Planetary Physics has estimated that planetary rings of Saturn can be more than 4.5 billion years old. 

Relevance of the Topic- Prelims: Questions based on planets and space missions.

About Saturn

• Saturn is the sixth planet in solar system position and is the second largest planet in the solar system after Jupiter.
• Saturn is the least dense planet in the Solar System with density even less than that of water. 
• Saturn is a gas giant dominated by hydrogen and helium. Its atmosphere contains hydrogen, helium, methane, ammonia, and other gases, giving it a yellowish-brown appearance.
• The mass of Saturn is 95 times the mass of Earth. However, Saturn's gravity is only 1.08 times the gravity on Earth. 

Saturn’s Rings: 

• Saturn’s rings are composed of dust and ice particles. These dark pieces of dust are omnipresent and constantly bombard the planet.
• There are seven rings named A, B, C, D, E, F and G. The Cassini division is the largest gap, located between the ring A and B.
• When it comes to the origin of rings, it is hypothesised that they may be remnants of shattered moons or comets. Some theories suggest an age of 100 million years.

Debate on the age of Saturn’s ring

One faction of scientists claim the age of Saturn’s rings to be about 100 million years, whereas, the new research has hypothesised that it can be more than 4.5 billion years old. 

1. Claims supporting young age of rings: 

The data of Cassini spacecraft of NASA, which orbited Saturn from 2004 to 2017, indicated younger rings due to following reasons: 

• Rings appear unusually bright and clean, predominantly composed of the water and ice with very little contamination of dust.
  • If the rings were old, then the omnipresent dark dust must have accumulated making rings dark. 
  • But as rings are clear, this suggests that rings are not that old enough to accumulate significant impurities.
• Minor darkening signs: When micrometeoroids collide with the ice particles in the ring they deposit dark material over time. As Cassini observed minor darkening it is believed that rings have not been exposed to cosmic impact for billions of years.

2. Reasons supporting old age of rings (4.5 billion years):

• Explanation of vaporisation mechanism: It is observed in the research that micrometeoroids vaporise after the impact with the rings.
  • When the micrometeoroids impact the ring with high velocity, the immense energy causes the micrometeoroids to vaporise upon impact. 
  • This leads to the ejection of the contaminants making the rings clean and clear. Therefore, clean rings does not imply that rings are new.
• The study posits that the rings could have formed during early stages of the solar system, aligning the age of Saturn itself.

Importance of studying Saturn’s rings

• Understanding evolution: Estimating the age of rings of Saturn can allow researchers to understand about the primordial conditions that shaped the planets and moons.
  • E.g., If the rings are 100-400 million years old, they are formed long after the solar system stabilisation, raising questions about what cataclysmic event created them.
• Clues about Saturn’s and its ring’s fate: It is often claimed that Saturn’s rings are facing disappearance due to a phenomenon called “ring rain”. Research to establish the age of 4.5 billion years could help to predict the future stability of Saturn’s moons and its rings.
• Understanding cosmic recycling mechanism: The vaporisation of micrometeoroids highlights the self-cleaning mechanism of the solar system that prevents debris buildup over billions of years.
• Providing impetus to human habitation: The study will help to understand the impact of rings on the moons (Saturn's moons like Enceladus) which are evaluated as the future habitation for humans. 

Note: 

• NASA is the primary agency that has sent missions to study Saturn, these are:
  • Pioneer 11 (1979): First flyby of Saturn. 
  • Voyager 1 and 2 (1980-81): First detailed image of Saturn and its rings. 
  • Cassini (1997-2017) explored Saturn and its moons. Revealed Titan’s methane lakes and water plumes on Enceladus. Both Titan and Enceladus are the moons of Saturn. 

Determining the true age of Saturn’s rings impacts our understanding of planetary evolution, solar system history, and even exoplanetary systems.

Context: Astrophysicists have observed the most energetic neutrino ever seen. The particle was spotted by the Cubic Kilometre Neutrino Telescope (KM3NeT), which is still under construction at the bottom of the Mediterranean Sea. 

Relevance of the Topic: Prelims: Key facts about Neutrinos; Cubic Kilometre Neutrino Telescope. 

Major Highlights: 

• KM3NeT detected an ultra-high energy neutrino having 30 times more energy than any previously detected neutrino. The energy was 220 petaelectronvolts.
  • An electronvolt is the energy of an electron accelerated by a voltage of just one volt.
• This means that the neutrino had:
  • 100 trillion times more energy than a typical particle at the centre of the Sun. 
  • Trillion times more energy than medical X-rays
  • Ten billion times more than the most dangerous radioactive particles. 
  • Twenty thousand times more energetic than any particle in the most powerful particle collider (Large Hadron Collider).
• It is anticipated that the particle came from outside the Milky Way galaxy; its exact source still remains to be detected.

What are Neutrinos?

• Neutrinos belong to a group of fundamental particles called leptons in the Standard Model of Particle Physics. 
• They have no electric charge and very little mass (nearly massless). 
• They are the second-most abundant particles after photons (particles of light) and the most abundant among particles that make up matter.
• They very rarely interact with matter and that is why they are called ghost particles. This means they can travel through vast distances, including entire planets, almost undetected.
• There are three main types of neutrinos: Electron neutrino, Muon neutrino and Tau neutrino. These particles are produced when particles called leptons interact with matter.
  • For example, when a type of lepton called a muon interacts with matter, the interaction produces a muon-neutrino. The same goes for electrons (electron-neutrino) and tauons (tau-neutrino). 
• Source of Neutrinos: Stars, Supernovae, Galaxies, Nuclear reactions. 

Cubic Kilometre Neutrino Telescope (KM3NeT)

• KM3NeT is a gigantic deep sea neutrino telescope, being built by an international collaboration of more than 300 scientists and engineers from 21 countries. The enormous device is still under construction.
• KM3NeT consists of two deep-sea components:
  • ARCA (Astroparticle Research with Cosmics in the Abyss): 3.4 km deep near Sicily, Italy, focused on detecting high-energy neutrinos.
  • ORCA (Oscillation Research with Cosmics in the Abyss): 2.4 km deep near Provence, France, to study low-energy neutrinos.
• KM3NeT will be made up of more than 6,000 light detectors inside the ocean. When the telescope is complete, it will cover about a cubic kilometre of sea.

Working

• Neutrino interacts with matter so weakly that it can pass through kilometres of ocean (and even thousands of kilometres of Earth itself) to reach the KM3NeT detector.
• Most of the neutrinos would pass through the detector unnoticed. In very rare cases, a neutrino will collide with a water molecule.
  • This collision will produce secondary particles (like muons etc.). 
  • These secondary particles travel faster in the water than the speed of the light in the water, thus producing a faint bluish glow known as Cherenkov radiation. 
  • The light detectors (KM3NeT’s optical sensors) will detect the Cherenkov radiation and send a signal to the surface.
  • By studying the pattern of Cherenkov radiation, scientists can reconstruct/ study the original energy of the neutrino and its direction. 

Why study Neutrino?

The study of neutrinos is an area of immense interest among particle physicists and astrophysicists. 

• Neutrinos can travel vast distances with minimal interaction, hence, they carry information about the early universe, moments after the Big Bang. Studying them can provide insights into the universe's evolution. 
• The mechanism by which neutrinos acquire mass is still not fully understood. Studying their properties might shed light on the Higgs mechanism and mass generation in general. 
• There are discrepancies between Standard Model's predictions (Neutrino is massless) and the observed behaviour of neutrinos (have non-zero mass). Studying these anomalies could lead to the discovery of new physics beyond the Standard Model.

Context: The European Space Agency’s (ESA) Euclid space telescope has discovered a rare ring of light (known as an Einstein ring) around a galaxy nearly 590 million light-years away from Earth.

Relevance of the Topic: Prelims: Einstein Ring; Gravitational lensing; Euclid space telescope. 

What is an Einstein Ring?

• An Einstein ring is a ring of light around a form of dark matter, galaxy or cluster of galaxies. It is an example of strong gravitational lensing.
  • Gravitational lensing is a phenomenon which occurs when a massive celestial object (such as a galaxy, cluster of galaxies or black hole) creates a strong gravitational field which distorts and amplifies the light (causes the light to bend/curve) from a distant object positioned directly behind it. 
  • The object causing the light to curve is called a gravitational lens.
  • Gravitational lensing can result in several types of image configurations, including an Einstein ring.

Discovery of the recent Einstein Ring: 

• The Einstein ring was discovered around NGC 6505, a galaxy that was first found in the 19th Century & is nearly 590 million light-years away from Earth.
  • NGC 6505 acted as the gravitational lens. It distorted and amplified the light coming from a distant unnamed galaxy, located 4.42 billion light-years away.
    • A light-year is the distance light travels in one year, which is 9.46 trillion kilometres.
  • The photos taken by Euclid show a bright ball of light in the centre with a bright, cloudy ring around it.

Rarity of Einstein Rings:

• Einstein rings are named after mathematician and physicist Albert Einstein, whose general theory of relativity predicted that light could bend and brighten around objects across the cosmos. 
• The first Einstein ring was discovered in 1987, and since then, several more have been discovered. 
• Notably, they are extremely rare — less than 1% of galaxies have an Einstein ring.
• Einstein rings are not visible to the naked eye, and can be observed only through space telescopes such as Euclid.

Why do scientists study Einstein Rings?

• Probing dark matter:
  • These rings help scientists investigate dark matter which has never been detected. Dark matter and dark energy together make up 95% of the universe.
  • This dark matter does not interact with light, but it does have a gravitational effect. Gravitational lensing thus allows us to indirectly detect dark matter. 
• Studying distant galaxies:
  • Einstein rings enable scientists to learn about distant galaxies, which otherwise might not be visible.
• Expansion of Universe:
  • They can also provide information about the expansion of the universe as the space between the Earth and other galaxies — both in the foreground and the background — is stretching.

About Euclid Space Telescope: 

• The Euclid Space Telescope was launched in 2023 from Cape Canaveral in Florida on a SpaceX Falcon 9 rocket by the European Space Agency (ESA). 
• The telescope is stationed 1.5 million km away from the Earth at the Lagrangian Point 2. 
• It will observe the shapes, distances, and motions of billions of galaxies spanning over 10 billion light-years over the next six years. 
• Objective:
  • To create the largest cosmic 3D map of the universe to better understand the distribution of dark matter and reveal the influence of dark energy in the early universe.
  • To understand the evolution of the Universe by looking at the light emitted from galaxies 10 billion years ago. 

Context: As per a recent study, the samples of the asteroid Bennu transported to Earth contain the basic building blocks for life and the salty remains of an ancient water world.

Relevance of the Topic: Prelims: Key facts about Asteroid Bennu; NASA's OSIRIS-REx spacecraft. 

Major Highlights:

• Scientists studied the material collected from asteroid Bennu by NASA's OSIRIS-REx spacecraft in 2020.
• Initial analysis of the sample had already revealed evidence of high-carbon content and water.
• The latest research has found that evaporated water on Bennu's parent asteroid left behind a "briny broth" of salts and minerals. This indicates that Bennu's parent asteroid once had pockets of liquid water. 
• The samples contain sodium-rich minerals and confirm the presence of amino acids, nitrogen in the form of ammonia and traces of real extraterrestrial organic material formed in space (and not a result of contamination from Earth).
• More testing is needed to better understand the Bennu samples, as well as more asteroid and comet sample returns. 
• Significance: The analysis of the sample suggests a non-terrestrial origin and provides the strongest evidence yet that asteroids may have planted the seeds of life on Earth. 

About Asteroid Bennu

• Bennu is a carbon-rich near-Earth small asteroid. It is just little less than 500 metres in depth. 
• It is expected to have formed around 65 million years ago, from the debris of a parent asteroid dating back some 4.5 billion years.
• It is classified as a near-Earth object because it passes relatively close to planet Earth, every six years.
  • The closest asteroids which travel within 1.3 AU (Astronomical Unit) of the sun are called near-Earth objects.
  • 1 AU is approximately equal to 93 million miles - the distance between the Sun and the Earth. 
• The samples from Bennu (around 122 grams of dust and pebbles) were brought to Earth in a capsule by the OSIRIS-REx mission in 2023.

About OSIRIS-REx Mission

• Origins, Spectral Interpretation, Resources Identification and Security-Regolith Explorer (OSIRIS REx) is an asteroid study and sample return mission by NASA. 
• The spacecraft set out in 2016 to study asteroid Bennu, and returned to Earth with a sample for detailed analysis in 2023. 
• OSIRIS-APophis EXplorer (OSIRIS-APEX): After successfully completing its mission to gather a sample of asteroid Bennu in September 2023, OSIRIS-REx was renamed OSIRIS-APEX. NASA has redirected OSIRIS-REx to track asteroid Apophis. 

Context: The Union Cabinet has approved the development of the Next Generation Launch Vehicle (NGLV) in September 2024. This initiative aims to enhance India's space capabilities with a focus on human spaceflight and lunar missions by 2040. 

Relevance of the Topic: Prelims: Key facts about Next Generation Launch Vehicle.  

About Next Generation Launch Vehicle (NGLV)

• Aim: To develop a new generation of human rated launch vehicles with high payload capability & reusability. 
• NGLV will undergo three developmental flights (D1, D2, and D3), with a target completion timeline of 96 months (eight years). Completion is expected by 2032. 
• A total budget of ₹8,240 crores has been approved for the program, covering development costs, three test flights etc. 

Specifications of NGLV: 

• NGLV is a three-stage partially reusable Heavy-lift launch vehicle, currently under development by the Indian Space Research Organisation (ISRO).
• Reusability: It will have a reusable first stage, which would be utilised 15 to 20 times, to make the launches more affordable.
• Length: NGLV is projected to have a liftoff mass of 1,000 tons and a height of 91 meters, significantly larger than the 43-meter LVM3. 
• Fuel: NGLV will have semi-cryogenic propulsion (refined kerosene as fuel with liquid oxygen (LOX) as oxidiser) for the booster stages. 
• Maximum payload capability: 30 tonnes to Low Earth Orbit (LEO).
  • Currently, ISRO has achieved self-reliance in launching satellites through operational vehicles like PSLV, GSLV, LVM3, and SSLV.
  • LVM3 has a maximum payload capacity of 10 tonnes to LEO and 4 tonnes to Geo-Synchronous Transfer Orbit (GTO).
  • NGLV will have 3 fold payload capacity compared to LVM3, while its cost will be only 1.5 times more.

Significance:

• NGLV will offer higher payload capacity and will have modular green propulsion systems.
• NGLV will allow for multiple reuses, reducing operational costs and increasing operational efficiency of the booster.
• NGLV's development will support both national and commercial missions, including:
  • Deployment of communication and earth observation satellite constellations to LEO, benefiting India's entire space ecosystem.
  • Bharatiya Antariksh Station, Indian crewed lunar missions by 2040 and other interplanetary exploration. 

Read More: ISRO’s Satellite Launch Vehicles