When Was Mars Habitable for Life?

At least two-thirds of Mars's surface is more than 3.5 billion years old, and Mars may thus hold the best record of the prebiotic conditions leading to life, even if life does not or has never existed there, which might have started developing as early as 4.48 billion years ago.

When was Mars habitable?

The report, published in the journal Nature Astronomy, stated that the lake was filled with sediments that eventually converted to a compacted sandstone. Scientists believe that the lake existed about 3.5 billion years ago when the planet had a thicker atmosphere needed to support liquid on the surface.

Was Mars ever in the habitable zone?

Earth is the only planet in our solar system's habitable zone. ... Mars, which is too far from the Sun to be in the habitable zone, once had flowing liquid water. Our robotic space missions there have found evidence of ancient lakes, and minerals that could only have formed in water.