COLD, DAMP MARS MAY HAVE HOSTED AN ANCIENT OCEAN

Northern parts of the Red Planet could have supported bodies of liquid 3 billion years ago

- Charles Q. Choi

New 3D climate simulations of the planet’s ancient atmosphere and water suggest a liquid ocean once existed in the northern lowland basin of Mars. This ocean may have persisted even when average global surface temperatures were below freezing. Although present-day Mars is cold and dry, decades of evidence suggests the ancient surface was covered with rivers, streams and lakes. Since water on Earth usually points to life, these old signs of water raise the possibility that the Red Planet was once home to life.

Earth and Mars likely had similar climates about 3 billion years ago, when life was spreading on our planet. However, scientists debate whether Mars was temperate enough to host an ocean of water. NASA’s Perseverance rover is one of many missions sent to Mars to assess the planet’s suitability for hosting ancient water.