Nasa’s Webb telescope spots ‘impossible’ early Milky Way-like galaxies ‘that shouldn’t exist’

Observation challenges understanding of how dark matter influences galaxy formation

Astronomers have discovered an early monster galaxy larger than Milky from more than 11 billion years ago, which they say could upend our understanding of the formation and evolution of the universe.

Using new data from the James Webb Space Telescope, scientists found that a massive galaxy in the early universe about 11.5 billion years ago has an extremely old population of stars which challenges previous understanding of the evolution of the cosmos.

The current understanding of the formation of galaxies predicts there were far fewer massive galaxies in early cosmic times.

However, extremely massive quiescent galaxies have now been observed with some as early as one to two billion years after the Big Bang which challenges previous theoretical models.

“This pushes the boundaries of our current understanding of how galaxies form and evolve,” study co-author Themiya Nanayakkara said in a statement.

“The key question now is how they form so fast very early in the Universe and what mysterious mechanisms lead to stopping them from forming stars abruptly when the rest of the Universe is doing so,” Dr Nanayakkara said.

The latest observation of the galaxy ZF-UDS-7329, described in the journal Nature, also upends our understanding of the role played by the elusive dark matter – a type of matter that does not interact with the electromagnetic force and is known to make up over 95 per cent of the Universe.

Since this type of matter does not absorb, reflect, or emit light, researchers have only been able to infer its existence from the gravitational effect it appears to have on visible matter.

Galaxy formation is known to be dictated by how dark matter concentrates, and models previously suggested there may not have been enough of this elusive matter to seed the formation of mega galaxies 11 billion years ago.

The new observations of mammoth galaxies during this time upends our understanding of how dark matter influences galaxy formation.

“Having these extremely massive galaxies so early in the Universe is posing significant challenges to our standard model of cosmology,” Claudia Lagos, another study author from the University of Western Australia, said.

“This is because we don’t think such massive dark matter structures as to host these massive galaxies have had time yet to form. More observations are needed to understand how common these galaxies may be and to help us understand how truly massive these galaxies are,” Dr Lagos said.