Origin story: All comets come from the same place next to the Sun

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Origin story: All comets come from the same place next to the Sun
Artwork shows a rocky planet being bombarded by comets.NASA/JPL-Caltech

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  • A new study indicates that all comets were born in the same place.
  • They originated next to Sun when it was younger, before the formation of planets.
  • The process took anywhere from 100,000 to 1 million years, which might explain the difference in the composition of comets.
Comets can be found flying all over the solar system, but all of them could have originated in the same place.

Scientists believe that comets were born right next to Sun, in the early universe.

It's only because planets started to form later, that these comets were flung all over space, according to a new study accepted in Astronomy and Astrophysics.

Origin story

Comets are made up of ice, dust and small rocks. Their composition is what sets them apart from asteroids — space rocks made up of clay, silicate and different metals.

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"We know what comets consist of and which molecules are present in them. They vary in composition, but are normally seen as just one group of icy balls. Therefore, I wanted to know whether comets are indeed one group, or whether different subsets can be made," said Christian Eistrup, the lead author of the paper.

He found that all comets were born somewhere close to the Sun. The Sun was fairly young at the time. It was — so young that it was still surrounded by the dense gas and dust that occurs when a new star is formed.

Planets were yet to make their way into existence, to form the celestial bodies that we are familiar with today.

As cold as ice

Eistrup was able to pin down the point of origin to a zone around the Sun where carbon monoxide was turning into ice. Next to the Sun, but far from its nucleus.

The distance allowed temperatures to dip between -250 degrees Celsius.
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Because it's so cold within that range, every molecule present was turned into ice.

Take your time

The birth of comets didn't happen overnight. It took anywhere between 100,000 years to a million years for comets to form.

The slow speed of reactions could explain why comets have varied composition even though they're born in the same place.

"Although we now think they formed in similar locations around the young Sun, the orbits of some of these comets could be disturbed - for instance by Jupiter - which explains the different orbits," stated Eistrup.

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The only thing is that Eistrup only had 14 samples to conduct his research. Ideally, more data on different comets would go a long way to confirm what they have already found.

Comets and Earth already have a very close connection. Scientists believe that it was comets crashing into the planet that first created life on Earth. "And if the right comet hits the right planet, with the right environment, life could start growing," said Eistrup.

See also:
Scientists have measured a comet's impenetrable shield in action for the 1st time

A bizarre interstellar object called 'Oumuamua continues to perplex astronomers a year after it vanished. Here's why a few scientists still wonder if it was alien.

Humans Just Got Our First Close-Up Look At A Comet And It's Mind-Blowing
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