by Bob Evans on
Apr 5, 2009
A 10-year study of 100,000 galaxies close to our own offers compelling proof that long-hypothesized "dark matter" does exist and is in fact a guiding force behind the structure of the universe, a team of Australian, British, and American astronomers revealed this week.
Saying that "the universe we see is really quite structured," one of the lead researchers explained that the 10-year "census" of galaxies near our own Milky Way offers powerful evidence that this invisible dark matter "seems to hold the galaxies together."
The dark matter's influence on galaxies "stops their constituent stars from flying off and it seems to be driving the large-scale galaxy clusters and super clusters" that are the largest objects in the universe, said Dr. Heath Jones of the Anglo Australian Observatory in an article on the website of the Australian Broadcasting Corporation.
Offering rich details about the direction, speed, shape, and evolving structure of 100,000 galaxies, the 10-year study offered great promise because of its exhaustive scope: it analyzed those dynamic properties for a much larger number of galaxies than any other study had ever attempted.
In reviewing the data from the study, Jones said, it became clear that directly observable visible objects could not possibly have exerted sufficient gravitational force to account for all of the movement and dynamics of the galaxies being studied.
And in hypothesing about what other, nonvisible forces could account for that additional gravitational effect, theories about dark matter completed that equation very nicely, he told the ABC:
"The galaxies just aren't uniform. They are scattered throughout the universe," he said. "What we find is that they tend to clump and cluster together. So you'll get galaxies clustering along nice delicate filamentary chains. You get some galaxies that will congregate in their clusters and you will get clusters of galaxies collecting in super clusters of galaxies, so the universe that we see is really quite structured….
"Astronomers know that this dark matter must exist in the universe," he said. "We can't see it with our telescopes directly, but by studying large objects like galaxies and how they move with respect to each other we can infer its existence quite accurately."
In addition to the compelling evidence the study provides for the existence of dark matter, Jones said, it also offers equally compelling proof that the universe is expanding and will continue to do so, rather than at some point collapsing back in upon itself as some astronomers have theorized.