What is Planet?
Three conditions for a celestial object to be called a ‘planet’ –
- it must orbit the Sun
- it should be massive enough to acquire an approximately spherical shape
- it has to ‘clear its orbit’ i.e. be the object that exerts the maximum gravitational pull within its orbit
‘Dwarf planets’, on the other hand, need to only satisfy the first two conditions.
- As per the third condition, if an object ventures close to a planet’s orbit, it will either collide with it and be accreted, or be ejected out.
- But, in case of Pluto, it is affected by Neptune’s gravity.
- It also shares its orbit with the frozen objects in the Kuiper belt.
- Based on this, the IAU deemed that Pluto did not ‘clear its orbit’ (the third rule).
What is Ploonets?
- Astronomers have defined a new class of celestial objects called “Ploonets,” which are orphaned moons that have escaped the bonds of their planetary parents.
- Planet + moon = Ploonet.
- The researchers explain that the angular momentum between the planet and its moon results in the moon escaping the gravitational pull of its parent.
NASA has reported the discovery of an Earth-size planet, named TOI
700 d, orbiting its star in the “habitable zone”.
- A habitable zone, also called the “Goldilocks zone”, is the area around a star where it is not too hot and not too cold for liquid water to exist on the surface of surrounding planets.
- Our Earth is in the Sun’s Goldilocks zone. If Earth were where the dwarf planet Pluto is, all its water would freeze; on the other hand, if Earth were where Mercury is, all its water would boil off.
- Life on Earth started in water, and water is a necessary ingredient for life as we know it.
- So, when scientists search for the possibility of alien life, any rocky exoplanet in the habitable zone of its star is an exciting find.
- An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmation of detection of exoplanet occurred in 1992.
- Exoplanets are very hard to see directly with telescopes. They are hidden by the bright glare of the stars they orbit.
- So, astronomers use other ways to detect and study exoplanets such as looking at the effects these planets have on the stars they orbit.
- M dwarf or M-type star, also called Red Dwarf Star are the most numerous type of star in the universe and the smallest type of hydrogen-burning star.
- These have masses from about 0.08 to 0.6 times that of the Sun.
- In the Milky Way Galaxy, about 70% of the stars are red dwarfs.
- The amount of magnetic flux that rises up to the Sun’s surface varies with time in a cycle called the solar cycle. This cycle lasts 11 years on average. This cycle is sometimes referred to as the sunspot cycle.
- Near the minimum of the solar cycle, it is rare to see sunspots on the Sun, and the spots that do appear are very small and short-lived. During “solar maximum”, there will be sunspots visible on the Sun almost all the time, and some of those spots will be very large and last several weeks.
- Sunspots are regions where the solar magnetic field is very strong.
- In visible light, sunspots appear darker than their surroundings because they are a few thousand degrees cooler than their surroundings.
- Sunspots do not appear everywhere on the Sun. They are usually concentrated in two bands, about 15 – 20 degrees wide in latitude, that go around the Sun on either side of the solar equator.
What’s the Difference Between a Comet, Asteroid and Meteor?
Where asteroids are located?
- Most asteroids lie in a vast ring between the orbits of Mars and Jupiter.
- Not everything in the main belt is an asteroid, for instance, comets have recently been discovered there, and Ceres, once thought of only as an asteroid, is now also considered a dwarf planet.
- Many asteroids lie outside the main belt. For instance, a number of asteroids called Trojans lie along Jupiter’s orbital path.
- Three groups — Atens, Amors, and Apollos — known as near-Earth asteroids orbit in the inner solar system and sometimes cross the path of Mars and Earth.
- Asteroid: A relatively small, inactive, rocky body orbiting the Sun.
- Comet: A relatively small, at times active, object whose ices can vaporize in sunlight forming an atmosphere (coma) of dust and gas and, sometimes, a tail of dust and/or gas.
- Meteoroid: A small particle from a comet or asteroid orbiting the Sun.
- Meteor: The light phenomena which results when a meteoroid enters the Earth’s atmosphere and vaporizes; a shooting star.
- Meteorite: A meteoroid that survives its passage through the Earth’s atmosphere and lands upon the Earth’s surface.
Heliosphere, Heliopause and Interstellar Space
- The sun creates heliosphere by sending a constant flow of particles and a magnetic field out into space at over 670,000 miles per hour. This stream is called the ‘solar wind.’
- Heliopause marks the end of a region created by our sun that is called the heliosphere.
- It is the boundary between our Solar System and the interstellar medium.
- It is the place where the sun’s constant flow of material and magnetic field stop affecting its surroundings.
- Interstellar Space is the part of space that exists between stars with cold particles around it.
- Inside the heliosphere, the solar particles are hot but less concentrated. Outside of the bubble, they are very much colder but more concentrated.
- Once an object arrives in interstellar space, there would be an increase of “cold” particles around it.
WHAT IS THE KUIPER BELT
The Kuiper Belt is similar to the asteroid belt found between the orbits of Mars and Jupiter, but it is 20 times as wide and somewhere between 20-200 times more massive. The ices are frozen volatiles that are made up of methane, nitrogen, ammonia and water.
At least three dwarf planets are located in the Kuiper belt: Pluto, Haumea and Makemake. Also, some of the solar system’s moons are thought to have originated there, such as Neptune’s Triton and Saturn’s Phoebe.
- Europa, a frozen moon around Jupiter, is believed to be one of the most habitable worlds in the solar system.
- It was first imaged in detail by the NASA’s Voyager 1 probe in 1979, revealing a surface almost devoid of large craters.
- Europa is also criss-crossed with long troughs, folds and ridges, potentially made of icebergs floating around in melt-water or slush.
- In 1990’s The Galileo mission found evidence that it had a sub-surface liquid salt water ocean.
- Recent studies shows it may well be normal table salt (sodium chloride), just like on Earth.
- This has important implications for the potential existence of life in Europa’s hidden depths.
- Scientists believe that hydrothermal circulation within the ocean, possibly driven by hydrothermal vents might naturally enrich the ocean in sodium chloride, via chemical reactions between the ocean and rock.
- On Earth, hydrothermal vents are thought to be a source of life, such as bacteria.
- Like our moon and Earth, Europa is tidally locked to Jupiter, meaning that it always presents the same side to the giant planet.
A team from the University of Colorado at Boulder is working on making the concept of artificial gravity a reality.
Meaning: Artificial gravity means spacecraft generating their own gravity by spinning around in space.
- These researchers are examining ways to design revolving systems that might fit within a room of future space stations and even moon bases.
- Under it, a short-radius centrifuge will rotate around the room, gathering more and more speed. The angular velocity generated by the centrifuge will push astronauts’ feet toward the base of the platform — almost as if he was standing under his own weight.
Application: It will one day help keep astronauts healthy as they venture into space, allowing humans to travel farther from Earth than ever before and stay away longer. Astronauts could crawl into these rooms for just a few hours a day to get their daily doses of gravity.
Present status: The concept of artificial gravity has so far as existed only in science fiction.
- A team of Indian astronomers have identified previously unknown, extremely large supercluster of galaxies called Saraswati
- Saraswati supercluster is one of the largest known structures in the nearby universe.
- It is 4 billion light years away from Earth and may contain the mass equivalent of over 20 million billion suns.
- It has 43 galaxies that may contain thousands of suns, besides having billions of stars, planets, other bodies, gases and dark matter.
- It is estimated to be stretched over 650 million light years in distance.
- The discovery of Saraswati supercluster will help astronomers in understanding galaxy formation and evolution, effect of superclusters on environment of the galaxies.
What is a Supercluster?
- A supercluster is a chain of galaxies and galaxy clusters.
- It is bound by gravity consisting of tens of thousands of galaxies.
- It often stretches several hundred times the size of clusters of galaxies.
- Thus, it can be said, galaxies are made of billions of stars and planets and grouped into clusters.
- These clusters of galaxies, in turn, are grouped together to form superclusters.
- The Milky Way, the galaxy in which earth is located is part of a supercluster called the Laniakea Supercluster.
Why do we need telescopes?
- To watch the object of faraway we need to have a bigger eye over which we can collect more light coming from an object.
- With more light we can create a brighter image, we can then magnify the image so that it takes up more space on our retina.
- That’s where the telescopes come, telescope lens work as a big eye to collect more light coming from an object.
- The big lens in the telescope (objective lens) collects much more light than an eye can from a distant object and focuses the light to a point (the focal point) inside the telescope.
How does telescope works?
- A smaller lens (eyepiece lens) takes the bright light from the focal point and magnifies it so that it uses more of retina.
- A telescope’s ability to collect light depends on the size of the objective lens, which is used to gather and focus light from a narrow region of sky.
- The eye piece magnifies the light collected by the objective lens, like a magnifying glass magnifies words on a page. But the performance of a telescope depends almost entirely on the size of the objective lens, sometimes called the aperture.
- Astronomers use a number of telescopes sensitive to different parts of the electromagnetic spectrum to study objects in space.
- Different detectors are sensitive to different wavelengths of light. In addition, not all light can get through the Earth’s atmosphere,
Types of observatories
- Radio waves can make it through the Earth’s atmosphere without significant obstacles, hence, we don’t need to put radio telescopes in space.
- However, space-based radio observatories complement Earth-bound radio telescopes in some important ways.A special technique used in radio astronomy is called “interferometry.
Radio astronomers can combine data from two telescopes that are very far apart and create images that have the same resolution as if they had a single telescope as big as the distance between the two telescopes. This means radio telescope arrays can see incredibly small details.
- The Earth’s atmosphere blocks much of the light in the microwave band, so astronomers use satellite-based telescopes to observe cosmic microwaves.
- The entire sky is a source of microwaves in every direction, most often referred to as the cosmic microwave background (or CMB for short). These microwaves are the remnant of the Big Bang, a term used to describe the early universe.
- While some infrared radiation can make it through Earth’s atmosphere, the longer wavelengths are blocked. But that’s not the biggest challenge – everything that has heat emits infrared light.
- That means that the atmosphere, the telescope, and even the infrared detectors themselves all emit infrared light.
- Another challenge is that Water vapor in the atmosphere absorbs much of the infrared radiation from space so the infrared observatories on Earth are located on high, dry mountains such as Mauna Kea in Hawaii.
- The Herschel Space Observatory was launched in May 2009 and the Spitzer Space Telescope was launched in August 2003.
- Astronomers study the infrared wavelengths to study the early universe and to learn about objects that are too cold to generate visible light including brown dwarf stars and dust clouds.
Visible spectrum observatories
- Visible light can pass right through our atmosphere, which is why astronomy is as old as humanity.
- Ancient humans could look up at the night sky and see the stars above them. Today, there is an army of ground-based telescope facilities for visible astronomy (also called “optical astronomy”). However, there are limits to ground-based optical astronomy.
- As light passes through the atmosphere, it is distorted by the turbulence within the air.
- Astronomers can improve their chances of a good image by putting observatories on mountain-tops.
- Visible-light observatories in space avoid the turbulence of the Earth’s atmosphere.
- In addition, they can observe a somewhat wider portion of the electromagnetic spectrum, in particular ultraviolet light that is absorbed by the Earth’s atmosphere.
- The Hubble Space Telescope observes from an orbit about 559 km above the Earth at wavelengths from near infrared through the visible range and into the ultraviolet.
- The Earth’s atmosphere absorbs ultraviolet light, so ultraviolet astronomy must be done using telescopes in space.
- Other than carefully-select materials for filters, a ultraviolet telescope is much like a regular visible light telescope.
- The primary difference being that the ultraviolet telescope must be above Earth’s atmosphere to observe cosmic sources.
- The Hubble Space Telescope and the UltraViolet and Optical Telescope on Swift can both perform a great deal of observing at ultraviolet wavelengths.
- X-ray wavelengths are another portion of the electromagnetic spectrum that are blocked by Earth’s atmosphere.
- X-rays also pose a particular challenge because they are so small and energetic that they don’t bounce off mirrors like lower-energy forms of light.
- Focusing X-ray telescope require long focal lengths. In other words, the mirrors where light enters the telescope must be separated from the X-ray detectors by several meters. However, launching such a large observatory is costly and limits the launch vehicles to only the most powerful rockets
- Two X-ray telescopes currently in space are the Chandra X-ray Observatory and the XMM-Newton.
Gamma ray observatories
- Not only are gamma-rays blocked by Earth’s atmosphere, but they are even harder than X-rays to focus. In fact, so far, there have been no focusing gamma-ray telescopes.
- Instead, astronomers rely on alternate ways to determine where in the sky gamma-rays are produced. This can be properties of the detector or using special “masks” that cast gamma-ray shadows on the detector.
- It might be surprising to know that astronomers can use ground-based astronomy to detect the highest energy gamma-rays. For these gamma-rays, the telescopes don’t detect the gamma-rays directly. Instead, they use the atmosphere itself as a detector.
- Studying gamma-rays helps astronomers learn more about many things including active galactic nuclei, blazars, gamma-ray bursts, pulsars and solar flares.
Square Kilometre Array (SKA)
- It consists of a supercomputer that will process the enormous amounts of data produced by the SKA’s telescopes.
- The total compute power will be around 250 PFlops — that’s 25 per cent faster than IBM’s Summit, the current fastest supercomputer in the world.
When complete, the SKA will enable astronomers to monitor the sky in unprecedented detail and survey the entire sky much faster than any system currently in existence.
The SKA Project:
The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, with eventually over a square kilometre (one million square metres) of collecting area.
Objectives: The SKA will eventually use thousands of dishes and up to a million low-frequency antennas that will enable astronomers to monitor the sky in unprecedented detail and survey the entire sky much faster than any system currently in existence.
Significance: Its unique configuration will give the SKA unrivalled scope in observations, largely exceeding the image resolution quality of the Hubble Space Telescope. It will also have the ability to image huge areas of sky in parallel a feat which no survey telescope has ever achieved on this scale with this level of sensitivity.
Whilst 10 member countries are the cornerstone of the SKA, around 100 organisations across about 20 countries are participating in the design and development of the SKA.
Location: Thousands of SKA antenna dishes will be built in South Africa (in the Karoo), with outstations in other parts of South Africa, as well as in eight African partner countries, namely Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia and Zambia. Another part of the telescope, the low-frequency array, will be built in Western Australia.
- CHEOPS – CHaracterising ExOplanet Satellite is a new telescope going to be launched by European Space Agency.
- Unlike, NASA’s Kepler and TESS mission, it is a follow-up mission for the study of exoplanets rather than a discovery machine.
- Thus, it will help in determining planet sizes and other information.
Spitzer Space Telescope
- The Spitzer Space Telescope is the final mission in NASA’s Great Observatories Program – a family of four space-based observatories, each observing the Universe in a different kind of light.
- The other missions in the program include the visible-light Hubble Space Telescope (HST), Compton Gamma-Ray Observatory (CGRO), and the Chandra X-Ray Observatory (CXO).
- The Spitzer Space Telescope was launched in the year 2003. It is a space-borne, cryogenically-cooled infrared observatory capable of studying objects ranging from the Solar System to the distant reaches of the Universe.
- It captures infrared light, which is often emitted by ‘warm’ objects that are not quite hot enough to radiate visible light.
LIGO (Laser Interferometer Gravitational-Wave Observatory)
What is LIGO?
- It is the world’s largest gravitational wave observatory and a wonder of precision engineering.
- It comprises of two enormous laser interferometers located thousands of kilometres apart, each having two arms which are 4 km long.
- It exploits the physical properties of light and of space itself to detect and understand the origins of Gravitational Waves (GW).
Sources of GW
- Mergers of black holes or neutron stars, rapidly rotating neutron stars, supernova explosions and the remnants of the disturbance caused by the formation of the universe, the Big Bang itself, are the strongest sources.
- There can be many other sources, but these are likely to be too weak to detect.
- The study of GW offers a new way to map out the universe by using gravitational-wave astronomy.
- Two LIGO detectors work as one unit to ensure a remarkable precision, which is needed to detect a signal as weak as a gravitational wave.
- Its detector components are completely isolated and sheltered from the outside world.
- Unlike optical or radio telescopes, it does not see electromagnetic radiation (e.g., visible light, radio waves and microwaves) because gravitational waves are not part of the electromagnetic spectrum.
- It doesn’t need to collect light from stars; it doesn’t need to be round or dish-shaped like optical telescope mirrors or radio telescope dishes, both of which focus EM radiation to produce images.
LIGO Project at a global level
- Two LIGO detectors are already operational in the U.S., at Livingston and Hanford.
- The Japanese detector, KAGRA, or Kamioka Gravitational-wave Detector, is expected to join the international network soon.
- LIGO India will come up in Maharashtra, which will also have two arms of 4 km length.
- The project aims to move one Advanced LIGO detector from Hanford to India.
- This project is a collaboration between the LIGO Laboratory and three lead institutions in the IndIGO consortium: Institute of Plasma Research (IPR) Gandhinagar, Inter University Centre for Astronomy and Astrophysics (IUCAA), Pune and Raja Ramanna Centre for Advanced Technology (RRCAT), Indore.
- It is an ultra-high precision large-scale apparatus, which is expected to show a unique “temperament” determined by the local site characteristics.
Significance of another detector in India
- To locate gravitational waves: Observations from a new detector in a far-off position will help locate the source of the gravitational waves more accurately.
- Identification of new sources: Nnew detector will increase the expected event rates, and will boost the detection confidence of new sources (by increasing the sensitivity, sky coverage and duty cycle of the network).
- Impact on Indian Science: The project will help Indian scientific community to be a major player in the emerging research frontier of GW astronomy. This major initiative will further inspire frontier research and development projects in India.
- Impact on industry: The high-end engineering requirements of the project (such as the world’s largest ultra-high vacuum facility) will provide unprecedented opportunities for Indian industries in collaboration with academic research institutions.
- Education and public outreach: A cutting edge project in India can serve as a local focus to interest and inspire students and young scientists. The project involves high technology instrumentation and its dramatic scale will spur interest and provide motivation to young students for choosing experimental physics and engineering physics as career options.
What is the technology being developed in India for LIGO India?
- Some of it includes design and fabrication of ultra-stable laser, quantum measurement techniques, handling of complex control system for enforcing precision control, large-scale ultra-high vacuum technology, data analysis and machine learning.
- This is not a complete list and the development of such indigenous technology is likely to result in many spin-offs for industry and research.
- The dramatic improvement from LIGO-India would come in the ability of localizing GW sources in the sky.
What are Gravitational Waves?
- These waves are ‘ripples’ in space-time caused by some of the most violent and energetic processes in the Universe.
- The strongest gravitational waves are produced by catastrophic events such as colliding black holes, the collapse of stellar cores (supernovae), coalescing neutron stars or white dwarf stars, the slightly wobbly rotation of neutron stars that are not perfect spheres, and possibly even the remnants of gravitational radiation created by the birth of the Universe itself.
Black Holes– A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.
Supernova- A supernova is the explosion of a star. It is the largest explosion that takes place in space. A supernova happens where there is a change in the core, or center, of a star. A change can occur in two different ways, with both resulting in a supernova.
- Neutron stars comprise one of the possible evolutionary end-points of high mass stars.
- Once the core of the star has completely burned to iron, energy production stops and the core rapidly collapses, squeezing electrons and protons together to form neutrons and neutrinos.
- A star supported by neutron degeneracy pressure is known as a ‘neutron star’, which may be seen as a pulsar if its magnetic field is favourably aligned with its spin axis.
Universe’s First Molecule
Scientists have detected the most ancient type of molecule in our universe in space for the first time ever.
- Helium hydride ion (HeH+) was the first molecule that formed when, almost 14 billion years ago, the falling temperatures allowed recombination of the light elements (hydrogen, helium, deuterium and traces of lithium) produced in the Big Bang.
- It is the first type of molecule (first molecular bond) that formed in the universe after the Big Bang.
- At that time, ionised hydrogen and neutral helium atoms reacted to form HeH+.
- Once the universe cooled down, hydrogen atoms started to interact with helium hydride, creating molecular hydrogen, which set the stage for star formation.
- From that point on, stars created the other elements of the cosmos.
- Despite its importance in the history of the early Universe, HeH+ has so far escaped detection in astrophysical nebulae — cloud of gas and dust in outer space.
- Helium hydride — a combination of helium and hydrogen — was detected roughly 3,000 light-years from Earth by NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA).
Stratospheric Observatory for Infrared Astronomy
- Stratospheric Observatory for Infrared Astronomy (SOFIA) is a Boeing 747SP jetliner modified to carry a 100-inch diameter telescope. It is a joint project of NASA and the German Aerospace Centre.
- It is flown at approx 45,000 feet, where its observations are not impacted by interference from Earth’s atmosphere.
- SOFIA returns to Earth after every flight, allowing scientists to regularly update the instrument with the latest technology. One of the most recent upgrades included adding a specific channel to detect signatures of helium hydride, which previous telescopes did not have.
NASA’s Kepler Space telescope
While this is the first Earth-sized planet discovered by TESS, other Earth-sized exoplanets have been discovered in the past, mainly by NASA’s Kepler Space Telescope, a since-retired telescope that monitored more than 530,000 stars. In the end, the Kepler mission detected 2,662 planets, many of which were Earth-sized, and a handful of those were deemed to be within their star’s habitable zone — where a balance of conditions could be suitable for hosting life.
About Kepler Mission:
Launched in 2009, the Kepler mission is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-sized and smaller planets in or near the habitable zone and determine the fraction of the hundreds of billions of stars in our galaxy that might have such planets.
About TESS mission:
The Transiting Exoplanet Survey Satellite (TESS) is a NASA mission that will look for planets orbiting the brightest stars in Earth’s sky. It was led by the Massachusetts Institute of Technology with seed funding from Google.
NASA’s Hubble Telescope
- The Hubble Space Telescope is a large telescope in space. NASA launched Hubble in 1990.
- It was built by the United States space agency NASA, with contributions from the European Space Agency.
- Hubble is the only telescope designed to be serviced in space by astronauts.
- Expanding the frontiers of the visible Universe, the Hubble Space Telescope looks deep into space with cameras that can see across the entire optical spectrum from infrared to ultraviolet.
- Using NASA’s James Webb Space Telescope researchers plan to investigate how new stars are born.
- For this, a natural phenomenon called “Gravitational lensing” is to be used.
- The gravitational field of a massive object will extend far into space, and cause light rays passing close to that object to be bent and refocused somewhere else.
- This phenomenon is ‘Gravitational lensing’, simply put, ‘mass bends light’.
- The effect is analogous to that produced by a lens.
- The more massive the object, the stronger its gravitational field and hence the greater the bending of light rays.
- It is just like using denser materials to make optical lenses results in a greater amount of refraction.
- In effect, these are natural, cosmic telescopes, called gravitational lenses.
- These large celestial objects will magnify the light from distant galaxies that are at or near the peak of star formation.
- The effect allows researchers to study the details of early galaxies too far away.
- Gravitational lensing happens on all scales,
- The gravitational field of galaxies and clusters of galaxies can lens light.
- On smaller objects such as stars and planets.
- Even the mass of our own bodies will lens light passing near us a tiny bit, although the effect is too small to ever measure.
- The Milky Way today forms the equivalent of one Sun every year, but in the past, that rate was up to 100 times greater.
- NASA now plans to look billions of years into the past in order to understand how our Sun formed.
- The programme is called ‘Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star Formation’, or TEMPLATES.
James Webb Space Telescope
- The James Webb Space Telescope (also called JWST or Webb) will be a large infrared telescope with a 6.5-meter primary mirror. The telescope will be launched on an Ariane 5 rocket from French Guiana in 2021.
- It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.
- Webb is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA).
Wide Field Infrared Survey Telescope (WFIRST)
- WFIRST is a NASA mission designed to study dark energy, perform galactic and extragalactic surveys, and explore exoplanets.
Telescope to Explore Origins of Universe: SPHEREx
NASA will launch a new space telescope mission Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) in 2023.
- The launch could help astronomers understand how the Universe evolved in the first place and how common the ingredients for life are within it.
- SPHEREx will survey the sky in optical as well as near-infrared light.
- Astronomers will use the mission to gather data on more than 300 million galaxies, as well as more than 100 million stars in Milky Way.
- The mission will create a map of the entire sky in 96 different colour bands.
- SPHEREx’s main goal is to search for the fundamentals of life — water and organic matter within the Milky Way.
- Beyond Milky Way, it will also be looking at the wider regions of the universe, where stars are born.
- This will give scientists targets for more detailed study in future missions, like NASA’s James Webb Space Telescope and Wide-Field Infrared Survey Telescope.
- It will deliver an unprecedented galactic map containing ‘fingerprints’ from the first moments in the universe’s history.
- It will provide new clues to one of the greatest mysteries in science that what made the universe expand so quickly less than a nanosecond after the Big Bang.
Indian Neutrino project
- The India-based Neutrino Observatory (INO) Project is a multi-institutional effort aimed at building a world-class underground laboratory with a rock cover of approx.1200 m for non-accelerator based high energy and nuclear physics research in India. The initial goal of INO is to study neutrinos.
- It is a mega-science project jointly funded by the Department of Atomic Energy (DAE) and the Department of Science and Technology (DST).
The project includes:
- Construction of an underground laboratory and associated surface facilities at Pottipuram in Bodi West hills of Theni District of Tamil Nadu.
- Construction of an Iron Calorimeter (ICAL) detector for studying neutrinos.
- Setting up of National Centre for High Energy Physics at Madurai, for the operation and maintenance of the underground laboratory, human resource development and detector R&D along with its applications.
What are neutrinos?
Neutrinos, first proposed by Swiss scientist Wolfgang Pauli in 1930, are the second most widely occurring particle in the universe, only second to photons, the particle which makes up light. In fact, neutrinos are so abundant among us that every second, there are more than 100 trillion of them passing right through each of us — we never even notice them.
Neutrinos occur in three different types, or flavours. These are separated in terms of different masses. From experiments so far, we know that neutrinos have a tiny mass, but the ordering of the neutrino mass states is not known and is one of the key questions that remain unanswered till today. This is a major challenge INO will set to resolve, thus completing our picture of the neutrino.
Why detect them?
Neutrinos hold the key to several important and fundamental questions on the origin of the Universe and the energy production in stars. Another important possible application of neutrinos is in the area of neutrino tomograph of the earth, that is detailed investigation of the structure of the Earth from core on wards. This is possible with neutrinos since they are the only particles which can probe the deep interiors of the Earth.
Why should the laboratory be situated underground?
Neutrinos are notoriously difficult to detect in a laboratory because of their extremely weak interaction with matter. The background from cosmic rays (which interact much more readily than neutrinos) and natural radioactivity will make it almost impossible to detect them on the surface of the Earth. This is the reason most neutrino observatories are located deep inside the Earth’s surface. The overburden provided by the Earth matter is transparent to neutrinos whereas most background from cosmic rays is substantially reduced depending on the depth at which the detector is located.
Chandra X-ray Observatory
- Chandra is the world’s most powerful X-ray telescope. Chandra, named for Indian-American physicist Subrahmanyan Chandrasekhar.
- It examines the X-rays emitted by some of the universe’s strangest objects, including quasars, immense clouds of gas and dust and particles sucked into black holes.
- X-rays are produced when matter is heated to millions of degrees.The hottest and most energetic areas are shown in purple
- ChandraX-ray Observatory observed light from exploded stars, million-degree gas, and material colliding around black holes and neutron stars.
- ARIES telescope is a joint collaboration between Indian, Russian, and Belgian scientists.
- The telescope is located at Devasthal, Nainital at a height of 2,500 metres
- The high end technology incorporated in the telescope enables it to be operated with the help of remote control from anywhere in the world
- The telescope will be used in the study and exploration of planets, starts, magnetic field and astronomical debris
- The scientists will also help in research of the structures of stars and magnetic field structures of stars.
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