Dark streaks on Mars that have puzzled scientists since their discovery in the 1970s are not evidence of water as many ...

On May 2, as sunlight crept over the Martian horizon, the Odyssey spacecraft captured Arsia Mons, a towering, long-extinct volcano, puncturing a glowing band of greenish haze in the planet’s upper ...

Arsia Mons, which dwarfs Earth's tallest volcanoes, and its two neighboring volcanoes are often surrounded by water ice ...