Shocking detection in deep space is the ‘holy grail’ for cosmologists

17 May 20184.91k Views

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This image shows the very distant galaxy MACS1149-JD1 as it was 13.3bn years ago, observed with ALMA. Image: ALMA (ESO/NAOJ/NRAO), Hashimoto et al

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The most powerful space telescopes on Earth have discovered traces of a common gas incredibly far into deep space, and that changes what we know about the Big Bang.

It is becoming apparent to many astronomers out there that space is so large and peculiar, any theory we happen to come up with on the origin of the universe by no means guarantees a solidified fact.

You only have to take a look at some of the recent discoveries – such as the confirmation of gravitational waves – to see that they are capable of turning the fields of astronomy and astrophysics on their head.

The latest such discovery was made by a team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) and the European Southern Observatory’s Very Large Telescope when observing the very distant galaxy MACS1149-JD1.

Seriously distant oxygen

By peering at the galaxy with these powerful instruments, the team detected a very faint glow emitted by ionised oxygen, with the infrared light being stretched to wavelengths more than 10 times longer by the time it reached Earth and was detected.

What makes this discovery so incredible is that the signal is believed to have been emitted 13.3bn years ago, not only making it the most distant oxygen ever detected, but it also shows stars were forming as soon as 250m years after the Big Bang.

“This galaxy is seen at a time when the universe was only 500m years old and yet it already has a population of mature stars,” said Nicolas Laporte, a researcher at University College London and second author of the new paper.

“We are therefore able to use this galaxy to probe into an earlier, completely uncharted period of cosmic history.”

‘Witnessing the birth of starlight’

Soon after the Big Bang, there was no oxygen in the universe, but the fusion processes of the first stars released it when they began to die.

The detection of oxygen at MACS1149-JD1 meant that these earlier generations of stars had already been formed and were expelling oxygen just 500m years after the beginning of the universe.

To determine when these earlier stars were formed, the team used infrared data taken with the Hubble Space Telescope and the Spitzer Space Telescope. It discovered that the observed brightness of the galaxy is well explained by a model whereby the onset of star formation corresponds to only 250m years after the universe began.

“Determining when cosmic dawn occurred is akin to the holy grail of cosmology and galaxy formation,” said Richard Ellis, co-author of the paper.

“With these new observations of MACS1149-JD1, we are getting closer to directly witnessing the birth of starlight. Since we are all made of processed stellar material, this is really finding our own origins.”

Colm Gorey is a journalist with Siliconrepublic.com

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