Astronomers are trapped in the exquisitely painful limbo of knowing exactly where to look for Martian life, but being unable to do so for fear of sabotaging the mission.

Astrobiologists are closer than ever before to finding evidence of extraterrestrial life. But with millions of planets in the universe, they first must narrow down their search.

Mars has teased us with traces of water for years now, but there’s finally evidence of liquid water flowing across its present-day surface — and with it, a real potential to find living, breathing Martians.

An immense 130-foot-thick slab of frozen water has been discovered beneath the surface of Mars. While astronomers have already found ice at the planet’s poles and traces of water in the soil, the sheer size of this sheet and its...