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 Did We Find Another Planet In Our Solar System? 5 Strange Ways We Will Get Into Space Engineers Get Inspired by Origamis for Solar Array Deployment How to Fix a Space Probe from a Billion Miles Away Why You Would Want to Go on a One-Way Trip to Mars How do we study the stars?