The universe could be more crowded than we thought
An international team of researchers has carried out an extremely precise survey of the observable universe, and estimated that there are around 10 times as many galaxies populating the cosmos than had previously been believed.
It is impossible to know the exactnumber of galaxies colonizing the universe. This is due in part tothe technological limitations of present-day telescopes, but is alsoan inevitable result of the vastness of the cosmos, which is soexpansive that the light from distant galaxies cannot be seen fromEarth. Therefore, what we can see makes up the observable universe,but astronomers know that there is a great deal more we cannot see.
These barriers have not preventedastronomers from giving it their best shot, though. Based on an analysis ofthe Hubble Deep Field and Ultra Deep Field imaging campaigns, astronomers had estimated that there were some 200billion galaxies waltzing their way across the unimaginable vastnessof the cosmos.
However, while this may soundimpressive, a fresh cosmic census is suggesting that astronomers hadbeen dramatically underestimating just how cramped our universereally is.
The international team of researchersbehind the new study used data from a number of observatoriesincluding Hubble, supplementedby advanced mathematical models capable of inferring the existence ofgalaxies that lie in the unobserved reaches of the universe.
Withthis data, the researchers created a 3D model, with which theyestimated the number of galaxies that existed in each of the epochs that make up thehistory of our universe.
The team concluded that there could bea staggering two trillion galaxiespopulating the observable universe. The vast majority ofthese galaxies lie beyond the detection threshold of our current daytelescopes, but when the introduction of the next generation of space- and ground-based observatories becomeoperational, many of these illusive galaxies will slip into sight.
"It boggles the mind thatover 90 percent of the galaxies in the universe have yet to bestudied", comments Christopher Conselice, of the University ofNottingham, who led the research team. "Who knows what interestingproperties we will find when we discover these galaxies with futuregenerations of telescopes? In the near future, the James Webb SpaceTelescope will be able to study these ultra-faint galaxies."