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Cosmos- New Dimensions

Nobel Prize in Physics 2019 was awarded recently.

Who are the awardees?

1. Noble Prize in Physics 2019 was awarded to three scientists for their contribution to the field of astrophysics.

2. Dr. James Peebles was awarded for theoretical discoveries in physical cosmology.

3. He predicted the existence of the cosmic microwave background radiation known as the ‘Afterglow of the Big Bang Explosion’.

4. The other half of the prize was jointly given to scientists Michel Mayor and Didier Queloz for the discovery of an exoplanet orbiting a solar-type star.

What is the cosmology and its theories?

1. Cosmology is a branch of astronomy that involves the origin and evolution of the universe from the Big Bang explosion event.

2. According to NASA, cosmology is the scientific study of the large-scale properties of the universe as a whole.

3. Cosmologists deal with concepts like string theory, dark matter and dark energy and whether there is one universe or many i.e. multiverse.

4. The branch began as a branch of theoretical physics developed from Einstein’s static model of the universe.

5. Present models of the universe hold two fundamental premises i.e. Cosmological Principle and Dominant role of gravitation.

6. Cosmological Principle was derived by Edward Hubble. It holds that a large sample like Universe looks the same from all positions and directions.

7.  Cosmology also deals with theories of universe origin such as

a) Steady-State theory

b) Big Bang theory

How are the origin theories different?

1. Steady-state theory

a) It states that the universe is always expanding but maintaining a constant average density.

b) According to the theory, the matter is being continuously created to form new stars and galaxies at the same rate that old ones become unobservable as a consequence of their increasing distance and velocity of recession.

c) A steady-state universe has no beginning or end in time. The average density and arrangement of galaxies are the same. Galaxies of all possible ages are intermingled.

d) The theory was first put forward in 1948 by British scientists Sir Hermann Bondi, Thomas Gold, and Sir Fred Hoyle.

2. Big Bang theory

a) This theory states that the whole universe was evolved from a single very dense point through an explosion, that is estimated to have occurred around 13.8 billion years ago.

b) The essential feature of the theory is the emergence of the universe from a state of extremely high temperature and density.

c) The modern version of the theory was developed by George Gamow and colleagues in the 1940s.

d) The theory predicts that definite amounts of hydrogen, helium, and lithium were produced.

When was the first evidence of exoplanet noted?

1. Exoplanet or extrasolar planet is a planet orbiting a star other than the Sun outside the Solar System.

2. In 1917, the first evidence of exoplanet called ‘Van Maanem 2’ was noted. However, the evidence was rejected.

3. In 1992, the first exoplanet, which was orbiting the star ‘PSR B1257’, was discovered. Since then, 4031 exoplanets are confirmed to date.

4. Out of these, at least 21 exoplanets are considered habitable. Most of the discovered exoplanets are ‘Rogue planets.’ Rogue planets are basically nomad or inhabitable planets.

Which missions have discovered exoplanets?

1. Hubble Space Telescope

a) It was launched in 1990 to discover extra-terrestrial life outside the solar system.

b) The Hubble telescope has discovered a number of exoplanets.

c) It is credited with the discovery of water on the exoplanet named ‘K2-18b’ for the first time.

2. Spitzer Space Telescope

a) It was launched in 2013. It is planned to retire in January 2020.

b) It is an infrared space telescope and has observed the exoplanets in infrared wavelengths.

3. Kepler Space Telescope

a) It was launched in 2009 by the National Aeronautics and Space Administration.

b) It is designated to monitor the main sequence stars and exoplanets.

c) It introduced the ‘modern era’ in the planet-hunting. It detected 2662 exoplanets.

4. TESS Mission

a) The Transiting Exoplanet Survey Satellite (TESS) is a space telescope for NASA's Explorers program launched in April 2018.

b) It is designed to search for exoplanets using the transit method in an area 400 times larger than that covered by the Kepler mission.

5. ASTROSAT Mission

a) ASTROSAT is India’s first dedicated multi-wavelength space observatory.

b) This scientific satellite mission endeavors for a more detailed understanding of our universe.

c) The mission enables the simultaneous multi-wavelength observations of various astronomical objects with a single satellite.