Mars is said to be just too small for water

Mars may be just too small to hold on to large amounts of water, a new study suggests.

While water is essential for life on Earth and other planets, and scientists have found evidence of water in Mars’ early history, the red planet has no liquid water on its surface today.

Researchers have suggested there could be a number of possible explanations as to why there is no longer any water on Mars, including a weakening of its magnetic field that could have resulted in the loss of a thick atmosphere.

However, the new study offers a more fundamental reason why today’s Mars looks so drastically different to Earth.

Kun Wang, assistant professor of Earth and planetary sciences in arts and sciences at Washington University , said: “Mars’s fate was decided from the beginning.

“There is likely a threshold on the size requirements of rocky planets to retain enough water to enable habitability and plate tectonics, with mass exceeding that of Mars.”

For the new study, the researchers used stable isotopes of potassium to estimate the presence, distribution and abundance of volatile elements on different planetary bodies.

Researchers measured the compositions of 20 previously confirmed Martian meteorites.

They found Mars lost more potassium and other volatiles than Earth during its formation, but retained more of these volatiles than the moon and asteroid 4-Vesta – two much smaller and drier bodies than Earth and Mars. According to the study, there was a welldefined correlation between body size and potassium isotopic composition.