What is a comet, and how is it formed?

Comets are sometimes known as ‘dirty snowballs.’ They were leftovers from billions of years ago when the development of stars and planets occurred. Comets in our solar system begin as large chunks of rock and ice drifting around in the Oort Cloud before racing around the sun with their characteristic large tails. When the gravity of a massive passing body, such as a star, becomes powerful enough, large pieces of ice are drawn away from the cloud and toward the sun. As the ice ball approaches the sun, the sun’s radiation begins to melt some of the ice that makes up the comet. 

The melted ice forms a gaseous tail that spreads away from the heat source (the sun). Thus, comets are formed. In this blog, we will further understand what is a comet.

The solar wind pushes the tail outward. The gravity of all the planets and stars it travels through keeps the comet moving and guides its path. When a comet enters our solar system, the sun is responsible for the majority of the gravity controlling the comet’s speed. As a comet gets closer to the sun, it accelerates due to the sun’s gravity, pulling on it more strongly as it gets closer.

In addition to traveling faster near the sun, the comet’s tail will lengthen as more ice evaporates.

Where do comets come from?

Comets are thought to have two origins.

The Oort Cloud is the birthplace of long-period comets (those that take more than 200 years to complete an orbit around the sun). The Kuiper Belt is the origin of short-period comets (those that complete an orbit around the sun in less than 200 years).

Jan Oort, a Danish astronomer, postulated that comets live in a massive cloud in the solar system’s outskirts, far beyond Pluto’s orbit. The Oort Cloud is the name given to this phenomenon. According to statistics, it might include a trillion comets and account for a considerable portion of the solar system’s mass. However, because the individual comets are so few and far away, scientists have no direct evidence of the Oort Cloud’s existence.

What brings comets near Earth?

A planet’s gravity or star can pull comets from their homes in the Kuiper Belt or Oort Cloud. The tug can redirect a comet toward the sun. These redirected paths of the comets resemble lengthy, stretched ovals.

As the comet is drawn closer and closer to the sun, it swings around behind the sun and returns to where it came from. Some comets collide with the sun and are never seen again. When the comet is in the inner solar system, it is either coming or going; that’s when we might see it in our skies.

What are the parts of a comet?

• The nucleus is a solid, frozen core in the center of every comet.
• The celestial object is nothing but a dust and ice ball that travels about 2000 miles per hour. When it gets closer to the sun, its speed increases, and it might travel over 100,000 miles(approx).
• Scientists assume that when comets are in the Kuiper Belt or Oort Cloud, they are little more than frozen nuclei.
• When a comet approaches the sun, it begins to heat up. The ice eventually melts and turns to gas. This can also cause gas jets to erupt from the comet, bringing dust.
• The coma is formed by the gas and dust that surrounds the nucleus.

How are the comet tails formed?

• As dust and gases rush away from the nucleus, sunlight and particles from the sun push them into a brilliant tail that spans millions of miles behind the comet. When astronomers researched these tails, they noticed that comets have two distinct tails.
• One seems white and is formed of dust. The dust tail trails behind the comet in a broad, gently curved path.
• The other tail is bluish and composed of electrically charged gas molecules or ions.
• The ion tail always points directly away from the sun.

Study of comets

• For thousands of years, people have been fascinated by comets.
• Due to the coma’s gas and dust, it was impossible to acquire a good picture of a comet nucleus from Earth.
• In recent years, several spacecraft have had the opportunity to observe comets up close.
• The Stardust mission of NASA recovered samples from Comet Wild 2 (pronounced ‘Vilt two’) and returned them to Earth.
• Scientists discovered that the particles were high in hydrocarbons, which are substances that humans regard to be the ‘building blocks of life.’

Key takeaways

• Comets are large dust and ice particles that surround the sun. These ancient materials from space, well known for their long, streaming tails, are relics from the solar system’s birth 4.6 billion years ago.
• The melted ice forms a gaseous tail that pulls away from the source. The gaseous tail gets scattered away from the heat source, which, in this case, is the sun.
• The Stardust mission of NASA successfully recovered samples from Comet Wild 2 (pronounced ‘Vilt two’) and returned them to Earth. Scientists have discovered that the particles had many hydrocarbons, substances that are thought to be the ‘building blocks of life.’

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FAQs

Q1. Is comet a shooting star?

Ans-Meteors (or shooting stars) are not the same as comets, though they are related.

A comet is a ball of ice and dust that orbits the sun (usually millions of miles from Earth) as the sun heats and vaporizes the ice in the nucleus, gas escapes, carrying dust particles with it.

Q2. What are 3 facts about comets?

Ans-Fun Facts about comets-

• Comets have two tails, one gas and one ion (gas).
• There are 6,619 known comets as of 2019
• There are an estimated 1 trillion comets in the Oort Cloud.
• The famed Halley comet appears every 75 or 76 years.

Q3. Is there a comet coming in 2022?

Ans– Unlike fast short-period comets, K2 PanSTARRS will remain visible in the sky for the rest of 2022. If you know where to look, you can still see the ice visitor from the distant Oort Cloud.