Green Comet

In News

• Recently discovered, Green Comet can be witnessed after nearly 50 thousand years and next expected to be seen after the same number of years.

About

• What is the ‘green comet’?
  • It approached the sun in the middle of January 2023, it is now moving away from it, along its own orbit.
  • The orbit indicates it 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.
    • It is the most distant region of our solar system and Home of the Comets. 
• Why the colour Green?
  • Comets are frozen rocky or gas-filled objects that are remnants of the formation of the solar system. 
  • Due to their composition, characteristics and the path they move in, they tend to leave a light behind them. 
  • Here, the comet itself is green (called the head of the comet) and emits a whitish light behind it (often called the tail of the comet).
  • The green glow is thought to arise from the presence of diatomic carbon – pairs of carbon atoms that are bound together – in the head of the comet. The molecule emits green light when excited by the ultraviolet rays in solar radiation.
• Distance from Earth:
  • The green comet could be at a distance of 2.5 light minutes from Earth, meaning a “mere” 27 million miles.
• Naming: 
  • It will be closest to Earth in early February of 2023.
  • Termed the C/2022 E3 (ZTF), the comet was named to refer to those who first spotted it – astronomers at the Zwicky Transient Facility (ZTF) in the US, in March 2022.
• Visible: 
  • Comets could be visible with telescopes and binoculars, and might even be visible to the naked eye under a clear night sky.
  • Northern Hemisphere: Comet will be seen in the morning sky, as it moves swiftly toward the northwest during January 2023. 
  • Southern Hemisphere: It’ll become visible in the Southern Hemisphere in early February 2023.
  • Specifically in India: In Indian skies, it can be spotted at 16° above the horizon in the Bootes constellation, when looking in the northwest direction.
• Gravity on Comets: 
  • 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. 
  • As they orbit near the Sun, they heat up and spew gases and dust into a glowing head that can be larger than a planet. 
  • The remains of dust following this burning up, from a distance, look like a trail of light to humans on Earth. 
  • Comets, therefore, have often been seen giving out blue or whitish light, or even green.
• Uniqueness of Green Comet:
  • It comes under the category of long-period comets, which take more than 200 years to orbit the Sun; the green comet is not easily spotted. 
  • With a highly elliptical orbit, the comet will head back to the Oort cloud and make its next appearance roughly 50,000 years later. 

Source: IE