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 Earth’s Selfie Satellite Mysterious Plumes on Mars Have Scientists Stumped Pluto – Planet or Not ? Fishy Robot Designed To Dunk Into Europa’s Oceans We Just Landed On A Comet! NASA Might Send a Helicopter to Mars