Published: Saturday, May 18, 2020
As space enthusiasts know, it’s very easy to become engrossed in the many fascinating developments in science. From missions to the moon surface to discoveries of exoplanets. As an astronomer, I am most excited about a development that has been largely ignored on Earth. It could have profound implications on how we understand life on Earth and its unique feature: the oceans.
On April 27, the Vera C. Rubin Observatory, which will be built in Chile, marked an important construction milestone. The primary mirror of the telescope has been coated with a reflective material, allowing it to catch light from objects that are too dim for us to detect regularly.
This critical component will allow us to answer a question that scientists have been trying to answer for years: where did our oceans originate?
Related: How did Earth get water? Scientists are now looking to ‘hyperactive comests’ as clues.
Although we know that Earth’s oceans are essential for life on Earth, we don’t yet understand how they formed. Some people believe that our oceans came from icy asteroids and comets farther out in our solar system. Recent discoveries of interstellar bodies like 2I/Borisov and ‘Oumuamua may also reveal how oceans reach planets orbiting other stars.
Some chemical properties of Earth’s oceans are not what we would expect to see if water had been present at the time the Earth was formed. Astronomers think that water was delivered to Earth after its formation, possibly from comets originating in the outermost reaches of our solar system such as the Kuiper Belt or Oort Cloud. However, when the European Space Agency’s (ESA) Rosetta mission measured properties of water on the Comet 67P/Churyumov-Gerasimenko, these chemical signatures did not match those of our oceans.
Dark comets, one of the most mysterious objects in our solar system, may hold the key to the mystery.
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Recently, we discovered seven dark comets hidden in asteroids near the Earth. They look like asteroids, which are rocky bodies without water ice. We noticed, however, that the dark comets were speeding up in an odd way.
Comets, which are smaller bodies like asteroids, also contain ices, such as carbon dioxide and water. As a comet gets closer to the sun and heats up, the ice turns into a gas, which is blown away from the surface. This produces a rocket like acceleration, as well as a tail made of dust and gas.
Our telescopes can see that these dark comets accelerate like comets, but they do not have tails. They could have brought Earth’s oceans if they had water ice.
If dark comets contain water, then they may be the missing piece in our understanding about how our oceans were formed. It’s possible that dark comets similar to them or those that were around in the past had water that was similar to our oceans.
‘Oumuamua is our first interstellar body. It was the first large object to pass through the solar system from another star system. As with the dark comets it disguised itself as a comet because it did not have a tail. However, it accelerated just like a comet. We think ‘Oumuamua and dark comets contain ices which were previously invisible and these ices are what fuels their acceleration when they heat up into gases.
Astronomers discovered rocky planets that orbit other stars and could harbor oceans or life. These exoplanetary systems ejected so many interstellar bodies like ‘Oumuamua, Borisov and others into the galaxy that only a small fraction must have passed through our solar system. These interstellar bodies could contain the same ingredients that could be essential for life to develop on planets orbiting other stars, like Earth.
Related: Exoplanets with alien life on them
We are still only at the beginning of our explorations. Many more disguised comets, both interstellar and solar system-born, are probably lurking in our neighborhood.
Rubin Observatory has now taken us one step closer to having orders of magnitude greater observing sensitivity. We will be able soon to see accelerations on new dark comets and hundreds of interstellar bodies in our solar system.
Could interstellar objects and dark comets be the source of Earth-like life? The Rubin Observatory will allow us to better understand the new populations of the solar system, and perhaps where we come from.
Darryl Seligman works as a research assistant in the Department of Astronomy of Cornell University. Seligman’s research is primarily focused on theoretical and computer-based planetary science and astrophysicists.
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Source: Space.com