Previously, there was a lot of water on Mars, scientists agree. But now the planet’s surface is completely dry. Researchers have put forward many hypotheses about the causes of this phenomenon.
The authors of the new work claim that they have found the main factor. In their opinion, Mars is too small to hold a large amount of water.
The fate of Mars was sealed from the start. There is probably a threshold for size requirements for rocky planets to hold enough water to support life and plate tectonics, and Mars is not massive enough.
Kong Wang, Associate Professor, Department of Earth and Planetary Sciences, Faculty of Arts and Sciences
The authors of the new work studied stable isotopes of potassium: it was used as an indicator for more volatile compounds such as water. They further estimated the potassium levels in 20 Martian meteorites they found on Earth.
As a result, it turned out that the Red Planet lost more potassium and other volatiles than the Earth during its formation, but retained more volatile elements than the Moon.
Researchers have found a connection between the amount of volatile elements and the mass of a space body. And they stated that there is a mass threshold for rocky planets so that they can hold liquid water. Such planets should be larger than Mars.