Scientists have used orbiters and rovers to find dried streams, lakes, and gullies on Mars that hint at its watery past, but their cavalry of robots has struggled to prove the Red Planet ever had an actual ocean.

A study suggests Mars takes its red hue from a type of mineral that forms in cool water, which could reveal insights about whether Mars was ever able to support life.

Thanks to new research techniques published today, scientists say that "our understanding of why Mars is red has been transformed."

A new study led by Brown University researchers shows how a water-rich mineral could explain the planet’s color, hinting at a wetter, more habitable past on the Red Planet.

New research shows that the red dust on Mars contains ferrihydrite, a water-rich iron oxide. It's evidence that the planet rusted in water.

Mars – dusty, dry, and desert-clad – was once so rich in water it had not just lakes, but oceans, according to a new study. Observations using ground-penetrating radar have revealed underground features consistent with beaches on the red planet,

New evidence from China's Zhurong rover suggests Mars once had Earth-like beaches with gentle waves and sandy shores approximately four billion years ago. Scientists using ground-penetrating radar have discovered hidden layers of rock beneath the Martian surface that point to the existence of an ancient ocean.

Data from China's Zhurong rover on Mars suggests an ancient ocean and strengthens evidence that the planet was once warm, wet, and habitable.

A Chinese rover found evidence of ancient beaches on Mars, suggesting the planet once had vast oceans 4 billion years ago. The discovery of sloping sand layers beneath the surface provides new insights into Mars' watery past.