Perseverance is now searching for water and other exciting stuff on Mars, but in 2011, scientists discovered a massive water vapour cloud 12 billion light-years away from Earth. The cloud is the world's oldest (dating back to when the universe was 1.6 billion years old) and greatest source of water that we are aware of. How big is it? It contains 140 trillion times the quantity of water found in Earth's oceans—an almost incomprehensible amount of space. According to EarthSky, the coolest space fact of all is that this vapour cloud is "feeding" a black hole and may also include enough gases, such as carbon monoxide, to allow the black hole expand to six times its current size.