Water is ubiquitous on Earth—about 70% of Earth's surface is covered by the stuff. Water is in the air, on the surface and inside rocks. Geologic evidence suggests water has been stable on Earth since about 4.

Researchers have discovered potentially the oldest evidence of hot water activity on Mars through the analysis of a 4.45 billion-year-old zircon grain from the Martian meteorite known as Black Beauty.

The study identified when water interacted with the meteorite and established that the dating was unaffected by events after it left Mars.

According to a new analysis of the Lafayette Meteorite, minerals within it formed in the presence of water 742 million years ago. It's a real breakthrough in the dating of aqueous minerals on Mars, and suggests that, sometimes, Mars might still be a little damp.

Scientists analyzing the 'Black Beauty' meteorite have discovered a zircon grain that hints at hydrothermal systems on early Mars.