Scientists Think Mars Once Had Water. So What Happened to It? Mars may have had a core similar to Earth’s. It’s possible that when it diminished, the planet’s water went with it. Facebook Prev Article Next Article Space Checkout these cool gadgets... Related Posts The 5 biggest discoveries from NASA’s Cassini spacecraft First Ever Confirmed Planet That Has No Sun to Orbit Asteroid Mining Mission Revealed by Planetary Resources, Inc. This Is How The Universe Began How Do We Find Dark Matter? This is Mars 4 Billion Years Ago According to NASA