Galaxy GN-z11

Why in news? 

• The process of star formation and the subsequent stellar evolution inevitably generates massive amounts of dust and makes the host galaxy opaque to some extent due to the apparent view of a thick veil around it.
• This phenomenon has been missing in GN-z11’s behaviour, leaving astronomers amazed beyond measure.

About Galaxy GN-z11:

• It was discovered in 2015 by the Hubble Space Telescope.
• It is located approximately 32 billion light years away from the Earth.

What is a galaxy?

• It is a huge collection of gas, dust, and billions of stars and their solar systems. A galaxy is held together by gravity.
• A galaxy starts to form through the accumulation of hydrogen gas in the form of a very large cloud called a nebula and this growing nebula develops localised clumps of gas.

How does star formation occur?

• Stars are born within the clouds of dust and scattered throughout most galaxies.
• Turbulence deep within these clouds gives rise to knots with sufficient mass that the gas and dust can begin to collapse under their own gravitational attraction.
• As the cloud collapses, the material at the centre begins to heat up. Known as a protostar, it is this hot core at the heart of the collapsing cloud that will one day become a star.

Q1) What is a star?

A star is a massive, luminous object that is held together by its own gravity and emits energy through nuclear fusion reactions at its core.

Source: A puzzling tale of distant galaxy GN-z11: the vanishing and reappearing dust veil

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