Astronomers devise new way to observe traces of the first stars

Alex Wilkins is a writer.

There is a new way to look back at the universe's first moments.

A radio telescope in the Australian desert detected a signal that looked like it came from hydrogen gas that was absorbed by the first stars.

The signal was twice as strong as expected and implied that the gas was much colder than thought.

Some astrophysicists proposed that this could have been from interactions with dark matter, but others called for more careful measurement. It's difficult to rule out noise pollution from nearby radio sources or problems with the instruments, since the signal should be 100,000 times weaker.

A new project called Radio Experiment for the Analysis of Cosmic Hydrogen (REACH) is being planned by a group of people at the University of Cambridge.

Thomas Greve is not involved with the project but he says that the setup has been improved. There are many effects that come into play when you need to detect a very, very minute signal.

Simulations of multiple-antenna observations will be improved over previous single-antenna observations in order to properly separate out the correct signal.

Greve says that these techniques haven't been used in the study of hydrogen emissions. This is the first time that it has been done in this way, and it is a very powerful technique.

Nature Astronomy is published in a journal.