. . . .the existence of what appear to be massive and mature galaxies during the universe’s infancy defied expectations – too big and too soon. So scientists were left to question the accepted ideas about the origin and development of the universe.. . . .and unravel the mystery of why so big, why so bright. . . . .
Images of six candidate massive galaxies, seen 500 to 800 million years after the Big Bang. One source at bottom left could contain as many stars as our Milky Way. Photo / Nasa via AP
The period in cosmological history called Cosmic Dawn lasted from about 100 million years to 1 billion years after the big bang and is marked by the formation of the first stars and galaxies in the universe.
Astronomers have discovered what appear to be massive galaxies dating back to within 600 million years of the Big Bang, during “Cosmic Dawn” <U> suggesting that bigger/brighter/more mature galaxies were present far earlier than expected <U/>– how is it these galaxies were so much bigger and brighter than standard models would have predicted considering their age?
While the new James Webb Space Telescope has spotted even older galaxies, dating to within a mere 300 million years of the beginning of the universe, it’s the size and maturity of these six apparent mega-galaxies that stun scientists. The young galaxies appeared too bright, too massive and too mature to have formed so soon after the Big Bang. As noted in Phys.Org, It would be like an infant growing into an adult within just a couple years.
“According to the standard model of cosmology, there should not be many very massive galaxies during cosmic dawn because it takes time for galaxies to grow after the Big Bang.
“Typically, a galaxy is bright because it’s big. But because these galaxies formed at cosmic dawn, not enough time has passed since the big bang. How could these massive galaxies assemble so quickly? Our simulations show that galaxies have no problem forming this brightness by cosmic dawn.”
“In our new paper, we show . . . .that the bursts of star formation produce flashes of light that can explain the seeming “too bright/large for their assumed age” galaxies observed by Webb. And the reason this is so significant is that we explain these very bright galaxies without having to break the standard cosmological model,” Faucher-Giguère added.
The findings centered upon a phenomenon called “bursty star formation.”
Reuters and PopSci.com and NZHerald