A press release from the Royal Astronomical Society yesterday indicates that astronomers have located some very distant – and therefore very old – signs of water.
The water vapor is thought to be contained in a jet ejected from a supermassive black hole at the center of a galaxy, named MG J0414+0534. The water emission is seen as a maser, where molecules in the gas amplify and emit beams of microwave radiation in much the same way as a laser emits beams of light.
“The radiation that we detected has taken 11.1 billion years to reach the Earth. However, because the Universe has expanded like an inflating balloon in that time, stretching out the distances between points, the galaxy in which the water was detected is about 19.8 billion light years away,” explained Dr. McKean.
Why is this cool? Well, because it tells us something about what the universe was like when it was only a fifth as old as it is now.
“This detection of water in the early Universe may mean that there is a higher abundance of dust and gas around the super-massive black hole at these epochs, or it may be because the black holes are more active, leading to the emission of more powerful jets that can stimulate the emission of water masers. We certainly know that the water vapour must be very hot and dense for us to observe a maser, so right now we are trying to establish what mechanism caused the gas to be so dense,” said Dr. McKean.
Wait a minute, you say. I thought black holes sucked everything in, even light. How can it be that a supermassive black hole is ejecting something like water so fast that it emits strong electromagnetic radiation?
That’s easy, I say. It’s because while there are powerful gravitational forces around a black hole, it’s only stuff that passes the hole’s event horizon that is (almost) sure to be sucked in.