Researchers in Australia have developed a new method of surveying the sky using radio telescopes that has allowed them to finally see what lies beyond the expanse of the Milky Way.
In a study featured in the Astrophysical Journal, Prof. Lister Staveley-Smith and his colleagues at the International Center for Radio Astronomy Research (ICRAR) were able to take a peek behind the Milky Way galaxy using CSIRO's Parkes Radio Telescope that has been fitted with a new receiver.
Scientists have long sought to find out what could be found in that area of space, particularly where a massive gravitational anomaly known as the Great Attractor that is located some 150 and 250 million light years away from the Milky Way.
Previous theories have suggested that this region possibly contains a large collection of stars and galaxies, but these have yet to be confirmed. The presence of the bright and expansive disk of the Milky Way has prevented astronomers from studying the area using visible wavelengths.
"The Milky Way is very beautiful of course and it's very interesting to study our own galaxy but it completely blocks out the view of the more distant galaxies behind it," Staveley-Smith said.
While the researchers tried to use various techniques to see pass the Milky Way, they were only able to peek through thick foreground layer of stars and dust after using radio observations of the sky.
The Great Attractor
Astronomers first became aware of the existence of the Great Attractor after conducting sky surveys in 1973 and in 1978. However, it wasn't until 1986 that they were able to provide estimates of where the gravitational anomaly could be.
The Great Attractor is believed to be somewhere in the vicinity of the constellations Norma (The Carpenter's Square) and Triangulum Australe (The Southern Triangle). This area of space also includes the Norma Cluster (Abell 3627) and a dense portion of the Milk Way.
Staveley-Smith and his team have been trying to find out more about the Great Attractor, which is said to have a gravitational force that is comparable to that of a million billion suns.
The phenomenon continues to be one of the biggest mysteries in astronomy, but the recent success of the ICRAR researchers in seeing beyond the Milk Way in their survey could provide an important piece to finally solving this cosmic puzzle.
Staveley-Smith said that they have yet to determine the potential cause of the acceleration of gravity in the Milky Way or where the phenomenon is coming from.
What they do know, however, is that the region is home to a large number of galaxies known as superclusters, and that the entire Milky Way is traveling toward these clusters at a speed over two million kilometers per hour.
The researchers were able to identify three dense galaxy concentrations as well as two new clusters, which could be contributing to the massive flow of galaxies toward that direction.
Study co-author Renée Kraan-Korteweg said that a galaxy is typically made up of 100 billion stars. Discovering hundreds of additional galaxies behind the Milky Way means that there is a large amount of mass in that area of space that scientists did not know existed until now.
