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 End of Cassini’s Odyssey Laniakea: Our home supercluster Astronomers Spot Square Hole In Sun Would You Lie Tilted Backwards For 60 Days For Science? What We Know About the Black Knight Satellite of Unknown Origin This Is How Astronauts Have Fun – They Make Viral ‘Space Oddity’ Videos