For the first time, scientists have succeeded in developing a map of the distribution of water in the galaxy, which existed when the 13.8 billion-year-old universe was still a cosmic youth. The galaxy, named J1135, is located about 12 billion light-years from Earth and can therefore be seen less than 2 billion years after the Big Bang.

Created by the Galaxy Observational and Theoretical Astrophysics (GOThA) team as part of the Scuola Internazionale Superiore di Studi Avanzati (SISSA) study, J1135’s water map has unprecedented resolution that can reveal galactic dynamics never before seen in the early universe.

Although water is an essential component of life, its existence in the universe has a purpose other than finding habitable zones. Scientists can use the distribution of water to tell the cosmic history of certain processes occurring in the galaxy. This is because water turns from ice to steam, indicating high-energy regions where stars and even black holes are born. In short, the presence of water vapor in a particular region of the galaxy indicates that something very important is going on there.

“Water can be found not just on Earth, but all over space, in different states,” said Francesca Perrotta, lead author of the study and a SISSA researcher. “For example, water in the form of ice can be found in so-called molecular clouds, which are dense regions of dust and gas where stars are born.”

“Water,” Perrotta continued, “covers the surface of interstellar dust grains that form the building blocks of these molecular clouds and the major catalysts for the formation of molecules in space.”

Perrotta also explained that there are times when something breaks the calm and coolness of these molecular clouds, such as the birth of a heat-emitting star or a black hole starting to feast on the energy-radiating surrounding matter.

Radiation from these destructive sources heats the frozen water and causes it to turn directly into a gas called water vapor in a process called sublimation. Then, as this water vapor cools, it emits infrared light that astronomers can observe.

“Astrophysicists can then observe this water vapor emission to map regions of the galaxy where energy is produced, giving us unprecedented insight into how galaxies form,” Perrotta said. Said.

These emissions data can also be combined with mapping specific molecules, such as carbon dioxide, to learn more about how galaxies have merged over time. But observing the first galaxies like J1135 wouldn’t have been possible without a little help from a phenomenon first called “gravitational lensing” in Albert Einstein’s general theory of relativity.

A deep dive into early galaxies, courtesy of Einstein

Einstein’s 1915 theory of general relativity basically assumes that massive objects distort the fabric of space and time, and proposes that time can be perceived in higher dimensions. This is analogous to the two-dimensional analogy of spherical weights placed on a stretched rubber sheet that creates indentations in the fabric. Just as more massive weights cause a plate to bend more, more massive space objects cause space-time to bend more. Other than that, actually the space-time warping happens in 4D via the time bit.

This curvature leads not only to what we know as gravity, but also to a really interesting phenomenon about light.

When light from a background source, for example an ancient star, passes through the space-time curvature created by a large galaxy between that background source and Earth, the curve of the light’s path past the intervening object depends on how close it comes to the curvature. After all, this means that light from the same object can reach our telescopes at different times.

As a result, the same background object can not only appear at multiple points in the same image, but can also be magnified by the effect, so these intermediate objects are described as “gravity lenses”. Source