Billions of years ago, during the Noachian and Hesperian periods (4.1 billion to 3 billion years ago), rivers carved valleys and lakes shimmered. As Mars' magnetic field faded and its atmosphere ...

In this day and age, most scientists agree that some water existed on the surface of Mars during the Noachian epoch, which was roughly 4.1 to 3.7 billion years ago.

The Noachian is an early time period on Mars with high rates of asteroid impacts and possibly the presence of an abundance of surface water. The exact interval is uncertain, ...

Billions of years ago, during the Noachian and Hesperian periods (4.1 billion to 3 billion years ago), rivers carved valleys and lakes shimmered. As Mars’ magnetic field faded and its atmosphere ...

This period covers two geological eras: the Noachian, which ran from 4.1 to 3.7 billion years ago, and the Hesperian, which endured from 3.7 to about 3 billion years ago.

During the Noachian, a powerful river emptied into this region, depositing a delta on top of the crater floor. This image from NASA's Perseverance Rover reveals sandstone at the base of Jezero Crater.

The Noachian era’s importance in the formation of Mars is characterized by a series of asteroid and comet bombardments that shaped the planet’s surface.

Billions of years ago, during the Noachian and Hesperian periods (4.1 billion to 3 billion years ago), rivers carved valleys and lakes shimmered.