According to a new study, Mars’ early atmosphere was denser and richer in hydrogen than its current rarefied gas envelope saturated with carbon dioxide.
The models showed that the main gases coming out of the early magma ocean were a mixture of molecular hydrogen and water vapor. Hydrogen is the lightest element in the universe, but in a dense atmosphere it acts as a powerful greenhouse gas. The team’s calculations show that there was enough hydrogen in Mars’ early atmosphere to keep warm oceans stable on the planet’s surface for millions of years.