8 Scintillating Facts About Comets

By Sonakshi Kandhari

March 14, 2023

What is a Comet? 

On a star-studded night, if you see a tail-shaped object trailing through the sky, it's a comet. They are composed of dust and snow and are found orbiting the sun.  Their existence dates back 4.6 billion years and were earlier called long-haired stars. Here are eight scintillating facts about a comet.

Could Be the Cause of Life on Earth

A sample collected from the comet Wild-2 contained the amino acid Glycine, which is an essential building block of life.  Research suggests that Earth and comet collisions could be the cause of generating the energy required for the synthesis of complex molecules.

Orbits the Sun

Comets come in varied sizes and can be broadly classified into two categories: short-period comets and long-period comets. While short-period comets take 200 years or less to orbit the sun, the long-period comets require more than 200 years for the same.

Thrive in Their Own Atmosphere

On coming into close contact with the sun, its heat makes the ice in the comet’s  nucleus melt and emit a gas. The gas radiates from the nucleus, resulting in the formation of a luminous atmosphere that extends up to 60,000 miles or more in diameter and is called the ‘coma’.

Not Much Different From a Dirty Snowball

The nucleus (centre-most portion) of the comet is made of dust, ice and rock. Hence,  it is one of the darkest objects in the solar system and reflects only 4% of the light that hits it.  The nucleus covers an expanse of less than 10 miles, and it lacks the mass that is required to give it a round shape.

Has Been Around for a Long Time

Comets are named by the Greeks after the Greek word ‘kometes’, which means long-haired. Halley’s is the first comet that was sighted; there is disagreement about whether it was first spotted by the Greeks or the Chinese.  This comet appears once every 76 years, and the next sighting is expected in July 2061.

The Cause of Meteor Showers 

Trailing along in their own orbits beside the sun, comets shed small rocks. These rocks leave in their wake a meteoroid stream or a dust trail. When the Earth passes through this stream, a meteor shower takes place.

Two-Tailed Not One

A comet has two tails: one is a dust tail, and the other is a plasma tail. The dust tail is made of small solid particles and is visible to the naked eye. The plasma tail is made of ionised gas, and this tail is easy to photograph but difficult to spot with the human eye.

Not a Spaceship or an Alien Base

People hold the misconception that a comet is a base for aliens or is actually a spaceship. But in reality, their existence was around the same time as the formation of planets and the sun. So far, approximately 4000 comets have been discovered, but research indicates that many more are waiting to be discovered.

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