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Current Affairs

Exoplanets and dark matter

Date: 14 October 2019 Tags: Space

Issue

The Nobel Prize in Physics has been awarded to three people: two of them for discovering for the first time a planet outside our solar system orbiting a Sun-like star and another one towards contribution to physical cosmology.

 

Background

The word planet is a general term that describes any celestial body that moves around a star. An exoplanet is a planet outside our solar system i.e an extra solar planet.

 

Details

  • The constellation Pegasus has a star 51 Pegasi which is some 50 light years away from earth.

  • The prize-winning duo discovered a planet orbiting it on October 6 1995. It was named 51 Pegasi b, as per astronomical conventions.

  • It is a gas giant, about half the size of Jupiter. It orbits its star in just four days.

  • According to NASA there are about 4000 confirmed discoveries of exoplanets.

  • Advanced research has helped exploration move beyond conventional ground based telescopes.

 Cosmology

  • After the Big Bang, the universe expanded and cooled to a few thousand degrees Celsius. This caused it to become transparent, allowing light to pass through it.

  • This ancient afterglow of the Big Bang is known as the cosmic microwave background (CMB).

  • Measuring the CMB’s temperature could provide information about how much matter had been created in the Big Bang.

  • It was also observed that the release of the light played a role in how matter could form clumps creating galaxies.

Dark matter

  • A lot of mass is needed to hold the galaxies together with the strength of their gravitational attraction. The mass was believed to be in form of neutrinos and was not visible. This ‘invisible’ mass is known as ‘dark matter’.

  • This matter is found to be all around us but we only feel it through its gravity and we cannot see it through other interactions. This is because it does not interact with light.

  • Over a period of time it was also found out that the dark matter is more prominent than the initial assumptions, about 75% of the universal mass.