NASA’s Hubble Space Telescope, which had its 31st anniversary earlier this year, has found six dead galaxies in deep space in a remarkable discovery.
The galaxies ran out of cold hydrogen gas needed to make stars when the universe was roughly 3 billion years old, considered the ‘most prolific period of star birth in its history,’ according to a statement from the U.S. space agency.
The six galaxies are known as MRG-M1341, MRG-M0138, MRG-M2129, MRG-M0150, MRG-M0454 and MRG-M1423.
Six dead galaxies have been in deep space, roughly 11 billion light-years away. The six galaxies are known as MRG-M1341 (pictured top left and right), MRG-M0138, MRG-M2129 (pictured bottom left and right), MRG-M0150, MRG-M0454 and MRG-M1423
The discovery was made by NASA’s Hubble Space Telescope (pictured), in conjunction with the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile
The discovery was made in conjunction with the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.
‘At this point in our universe, all galaxies should be forming lots of stars. It’s the peak epoch of star formation,’ Kate Whitaker, a University of Massachusetts, Amherst assistant professor of astronomy and the study’s lead author, said in the statement.
‘So what happened to all the cold gas in these galaxies so early on?’
For now, scientists are not sure why the galaxies ran out of the gas 11 billion years ago, leaving them to speculate.
‘Did a supermassive black hole in the galaxy’s center turn on and heat up all the gas? If so, the gas could still be there, but now it’s hot,’ Whitaker added.
‘Or it could have been expelled and now it’s being prevented from accreting back onto the galaxy.’
Whitaker continued: ‘Or did the galaxy just use it all up, and the supply is cut off? These are some of the open questions that we’ll continue to explore with new observations down the road.’
It’s likely these galaxies will never rejuvenate, even if other galaxies merge with other small galaxies nearby.
By absorbing other galaxies, it ‘puffs up’ the dead galaxies and if for some reason, they do start to create new stars, it is akin to ‘a kind of frosting,’ Whitaker added.
Despite the lack of star formation, these galaxies are believed to have evolved and grow.
The galaxies were studied as part of the Resolving QUIEscent Magnified Galaxies At High Redshift (REQUIEM) program, which looks at distant galaxies that appear red in color.
A technique known as ‘gravitational lensing’ was applied to find the galaxies, Whitaker said.
‘By using strong gravitational lensing as a natural telescope, we can find the distant, most massive, and first galaxies to shut down their star formation,’ Whitaker explained.
‘I like to think about it like doing science of the 2030s or 40s – with powerful next-generation space telescopes – but today instead by combining the capabilities of Hubble and ALMA, which are boosted by strong lensing.’
The study has been published in the scientific journal Nature.
The universe is widely believed to be roughly 14 billion years old, based on the Hubble Constant of 70
The universe is widely believed to be roughly 14 billion years old, based on the Hubble Constant of 70.
In 2019, scientists in a separate study suggested that the Hubble Constant is 82.4, which would make the universe around 11.4 billion years old.