We’re Talking Big Here
WASHINGTON (AP) _ Astronomers in New Mexico say they have identified the biggest known structure in the universe, an enormous string of galaxies that offers tantalizing hints about the origin and possible fate of the universe itself.
The ″filament″ of galaxies and clusters of galaxies stretches more than one billion light years, or about six trillion billion miles, according to the astronomers who reported their findings last week to the National Science Foundation here.
In a telephone interview, Dr. Jack Burns, associate astronomy professor at the University of New Mexico, said the identification that he and graduate student David Batuski made provides new evidence there is much more to the universe than the stars and other visible matter.
And it also is a new indication that galaxies such as our own Milky Way were formed through condensation and fragmentation from enormous-size clouds of gas, rather than the other way around, he said.
Without much more than the visible matter, there simply wouldn’t be enough mass, enough gravitational force, to hold such a huge supercluster of galaxies together, he theorized.
Growing evidence of the existence of greater amounts of gravitational force also lends support to theories that the ″end rse in a number of billions of years will begin contracting down into what some people have called a ’big crunch.‴
Although the newly identified filament is the largest yet identified, it isn’t the first. Astronomers using radio telescopes in West Virginia and Puerto Rico identified one about 700 million light years long three years ago, and other smaller ones have also been discovered.
Burns said that in light of the existence of such superclusters, ″we must postulate the existence of a dominant component of the universe consisting of non-luminous matter.″
He said no one really knows what that is, though he suggested it might consist of ″some form of dark or unseen matter such as exotic particles predicted recently by high energy physicists.″
It is even possible, Burns said, that all matter in the universe is connected ″much like a giant sponge with quite large holes in it. That view isn’t necessarily inconsistent with our findings.″
But he said much work remained to be done in a field that is still very new in astronomy.
He said he and his colleague identified the supercluster on which they’re reporting from among the first three target areas they focused on. It is in the direction of the constellations Perseus and Pegasus and lies between 200 million and one billion light years from Earth.
The discovery, Burns said, ″may have been dumb luck. We don’t know if something like this is common or rare.″
As recently as a decade ago, he said, technology wasn’t advanced enough to track the three-dimensional size of supercluster filaments. In addition to telescopic photos, he used a sophisticated ″electronic spectrograph,″ which uses a color-spectrum breakdown of light from galaxies to determine their speed through the universe and, ultimately, their distances and positions within a filament.
Part of the work was done on the National Optical Astronomy Observatories’ 84-inch telescope at Kitt Peak in Arizona.
The research, financed by the National Science Foundation, is to be published Dec. 1 in the Astrophysical Journal.