A massive ancient ocean once covered nearly half of the northern hemisphere of Mars making the planet a more promising place for alien life to have gained a foothold, Nasa scientists say. The huge body of water spread over a fifth of the planet’s surface, as great a portion as the Atlantic covers the Earth, and was a mile deep in places. In total, the ocean held 20 million cubic kilometres of water, or more than is found in the Arctic Ocean, the researchers found. Read the Full Article at The Guardian.