There’s Water Out There — WAY Out There!

You know that stuff that falls out of the sky, runs through rivers, fills the oceans, makes up ice cubes here in our refrigerators on Earth? That water stuff?  Well, it can be found in some pretty distant reaches of the cosmos, not just here on good ol’ planet Earth (or locked away on a Martian polar ice cap or under Europa’s shimmering icy surface). Astronomers have found signs of water in a very distant part of universe. It’s actually water vapor contained in a jet ejected from a supermassive black hole that lies billions of light-years away from us.  That water vapor existed near the black hole at a point about 2.5 billion years AFTER the Big Bang. That is an incredibly long time ago, and shows us the scene at a time when the universe was still quite young.

The black hole is jackhammering out of a galaxy called MG J0414+0534, and what the astronomers saw was the telltale fingerprint of water vapor in emissions from something called a maser. This is a region of gas where molecules in the gas amplify and emit beams of microwave radiation in much the same way as a laser emits beams of light. For it to show the fingerprint of water vapor scientists detected means that the gas-emitting region is hot and dense enough to heat water to its boiling point.

This water maser emission is not something you can see with an optical telescope. You need radio telescopes like the Extended Very Large Array and the Effelsberg radio telescope that can detect the emissions, and you need a gravitational lens. The gravitational lens acts as if it was a telescope, bending and magnifying light from the distant galaxy to make a clover-leaf pattern of four images of MG J0414+0534.