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 NASA’s Crazy Plan to Send a Space Submarine to Titan United Nations Developing Asteroid Defense Plan Boeing Awarded First Commercial Manned Space Mission Contract Nearby Exoplanet’s Hellish Atmosphere Measured More Than 200,000 Apply For One-Way Trip to Mars Should We Build a Dyson Sphere?