How Mars Lost its Water: Study Pinpoints the Path of the Planet's Escape

New research traces the atoms escaping into space to look back 4 billion years

Today, the Red Planet is a dry, inhospitable desert. But billions of years ago, Mars had a much thicker atmosphere and may have boasted rivers, lakes, and possibly even oceans.

Where did all that water go? New research published in the journal Science provides some answers. The study is the first to directly measure the escape of hydrogen atoms from Mars' upper atmosphere into space.

By combining data from the Mars Atmosphere and Volatile Evolution spacecraft with measurements from the Hubble Space Telescope, the team of researchers was able to trace the path of hydrogen atoms as they escaped the planet's gravity.

The Findings

The study found that the hydrogen atoms were escaping from Mars' upper atmosphere at a rate of about 100 grams per second. This may not seem like much, but over time, it adds up.

About 4 billion years ago, Mars' atmosphere was about 100 times thicker than it is today. The new study suggests that the planet lost about 60% of its water over the course of its history.

This loss of water has had a profound impact on Mars' climate. Without a thick atmosphere to trap heat, the planet's surface has cooled significantly. The loss of water has also made it impossible for liquid water to exist on the surface of Mars.

The Implications

The new study provides important insights into the history of water on Mars. It also has implications for our understanding of the search for life beyond Earth.

If Mars once had a thick atmosphere and liquid water, it is possible that it could have supported life. However, the loss of water has made it much less likely that life could exist on the Red Planet today.

The study also suggests that the search for life beyond Earth should focus on planets with thick atmospheres and liquid water. These are the planets that are most likely to have the conditions necessary for life to evolve.