Super-Earths: Interiors Cracked Open in New Study

When one hears the term "super-Earth" one may venture to guess that the definition is "an Earth-like planet with super powers." Well, in reality that is not too far off. A group of scientists from the Moscow Institute of Physics and Technology (MIPT) used mathematical models to "peer" inside the interiors of super-Earths and found compounds which defy the the laws of chemistry.

The substances they found boost the heat transfer rate -- the difference in temperature between the solid surface and surrounding fluid area -- and also enhance the magnetic field on the planet, according to the findings published in Scientific Reports. Lead researcher Artem Oganov and his team worked to discover what kinds of compounds consisting of magnesium, oxygen, and silicon would form in varying high pressure situations. The scientists did so by applying an algorithm called USPEX, which Oganov had previously developed to identify new substances in a former experiment.

To clarify, Super-Earths are planets that are heavier than Earth that orbit stars. Astronomers have identified two of these planets: Gliese 832c, which weighs five times as much as Earth and mega-Earth Kepler-10c, which weighs 17 times as much as Earth. However, there is no super-Earth in the solar system.

Planets like Earth are made up of a "thin silicate crust, a silicate-oxide mantle-which makes up approximately 7/8 of the Earth's volume and consists more than 90 percent of silicates and magnesium oxide-and an iron core," Oganov explained in an official statement. "We can say that magnesium, oxygen, and silicon form the basis of chemistry on Earth and on Earth-like planets."

The researchers used pressures that could possibly exist in the interiors of these planets-5 to 30 million atmospheres-to see what compounds of magnesium, silicon, and oxygen would take shape. Unusual compounds such as MgSi3O12 and MgSiO6 crystallized under the pressure. These compounds have more oxygen than the typical MgSiO3 found on planet Earth.

According to the researchers, the MgSiO compounds found on Earth are typically semiconductors or poor conductors. In this case, MgSi3O12 is a metal oxide and a conductor, which means the super-Earths have a stronger magnetic field through the absorption of electrical currents, and in turn a more agreeable environment for organisms to thrive.

Additionally, the mathematical formula showed MgSiO compounds that do not comply with the classical rules of chemistry, such as SiO, SiO3, MgO3, MgO2 and Mg3O2; the implications of these "forbidden substances" are still unknown.

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