Astronomers recently spotted a comet using the wide-field survey camera at the Zwicky Transient Facility (ZTF) in the US, which is appearing near earth after nearly 50,000 years.

 

What are Green comets?

  • Comets are frozen rocky or gas-filled objects that are remnants of the formation of the solar system.
  • The solid portions of a comet which is mostly water ice with embedded dust particles.
  • When near the sun, the icy cometary surfaces vaporise and emit large amounts of gas and dust, resulting in a massive atmosphere and tails.
  • The fluorescence of these gases, and especially the reflection of sunlight from the minute dust particles in the comet’s atmosphere and tail, is what gives these objects their visual impact.
  • Just like other bodies in space, comets also have orbits. They are sometimes pulled in close to the sun because of the sun’s gravity acting on them.
  • The orbit indicates this comet comes from the edge of our solar system, a distant reservoir of comets we call the Oort cloud.
  • The Oort cloud is thought to be a big, spherical region of outer space enveloping our sun, consisting of innumerable small objects, such as comets and asteroids.

 

What is the reason for the Green colour?

Laboratory research has linked this green-like aura to a reactive molecule called dicarbon, which emits green light as sunlight decays it.