MG J0414plus0534

MG J0414+0534 is an ancient, distant galaxy with very early signs of hydrogen dioxide water. The water vapor is thought to be contained in a maser, a jet ejected from a supermassive black hole at the center of the galaxy. The radiation from the water maser was emitted when the Universe was only about 2.5 billion years old, a fifth of its current age. The radiation took 11.1 billion years to reach the Milky Way galaxy. 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.

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 faint signal is only detectable by using a technique called gravitational lensing, where the gravity of a massive galaxy in the foreground acts as a cosmic telescope, bending and magnifying light from the distant galaxy to make a clover-leaf pattern of four images of MG J0414+0534. The water maser was only detectable in the brightest two of these images.