Exoplanets: Earth is far from being unique!

Do you see our planet as an exception? You are mistaken, say astronomers from the University of California at Los Angeles (UCLA – United States). The UCLA researchers were even forced to invent a method of their own for this purpose. A technique based on the study of the atmosphere of white dwarfs and which gave them access to the geochemistry of rocks that can be found outside our Solar System.

It should be remembered that white dwarfs are the remains of relatively small stars that have used up their nuclear fuel. These are incredibly dense objects. It is said that a teaspoon of their material weighs no less than 5 tons. They are thus able to attract heavy elements to them. And astronomers have already found carbon, oxygen, nitrogen or even silicon, magnesium or carbon in them.

Lots of Planets similar to Earth

More than a third of solar systems with recently detected giant planets are believed to have planets such as Earth, with deep oceans that support life. It is the result of a study done by researchers at the University of Colorado (Boulder, USA) and Pennsylvania State University.

The study focused on a different type of planetary system from our solar system, where gas giants, “hot Jupiters,” are in orbit very close to their stars, some even closer to them than Mercury is to the Sun. Scientists believe that such planets migrated towards their stars as the planetary system formed, disrupting the surrounding space and triggering the formation of planets like the Earth, covered with oceans, located in “habitable zones,” favorable to the evolution of life.

At the same time, the forces of the surrounding hot dense gas slow down the small ice bodies in the outer regions of the disc, dragging them into an inward spiral movement, delivering water to young planets. These could include oceans several thousand kilometers deep. A new class of planets, covered with oceans, located in solar systems different from ours, which may be habitable, would be defined in this way.

Oxidized rocks

But let us return for a moment to our Solar System to notice that the stones of the planets that make it up to appear strangely oxidized. Oxygen levels are up to 100,000 times higher than those found in our Sun.

By measuring the abundance of oxidized iron in the rocks that fell in the white dwarfs they were studying, astronomers were able to show that these rocks had similar chemical properties to those found on Earth. And as researchers believe that the phenomenon of oxidation influences the composition of a planet’s atmosphere, nucleus, and rocks, these results suggest that the chances of encountering Earth-like rocky exoplanets are high.