Something’s drawing in the Milky Way and other galaxies with the force of a million billion suns.
Using CSIRO’s Parkes 64-meter-long radio telescope located in Australia, astronomers have managed to peer through the galactic mass and stardust of the Milky Way, discovering hundreds of galaxies that were previously hidden from view — and they are shedding light on a mysterious gravitational anomaly known as the Great Attractor.
Although these new galaxies are only 250 million light-years from Earth — close in astronomical terms — they were hidden from view, until now, by our Milky Way galaxy.
“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,” said lead author Lister Staveley-Smith, from The University of Western Australia’s International Centre for Radio Astronomy Research (ICRAR) in a press release.
The newly found galaxies lie in an area astronomers call the Zone of Avoidance (ZOA) — getting its name because our view of this region had always been obstructed by the stars and planets that make up the Milky Way.
Astronomers have been trying to map this region for decades without any success, but luckily the Parkes telescope, with its new 21-centimeter multibeam receiver, has allowed astronomers to map the sky 13 times faster than they could before.
“We've used a range of techniques but only radio observations have really succeeded in allowing us to see through the thickest foreground layer of dust and stars,” said researcher Renée Kraan-Korteweg from the University of Cape Town in South Africa in a statement. “An average galaxy contains 100 billion stars, so finding hundreds of new galaxies hidden behind the Milky Way points to a lot of mass we didn't know about until now.”
The team found 883 galaxies — a third of which had never been seen before — and the researchers hope they can shed some light on the mysterious Great Attractor region, which appears to be drawing the Milky Way and hundreds of thousands of other galaxies towards it with a gravitational force equivalent to a million billion suns.
The Great Attractor is an anomaly because it deviates from our current understanding of the universal expansion of the universe.
“We don't actually understand what's causing this gravitational acceleration on the Milky Way or where it's coming from,” said Staveley-Smith. “We know that in this region there are a few very large collections of galaxies we call clusters or superclusters, and our whole Milky Way is moving towards them at more than two million kilometres [1.2 million miles] per hour.”
The team identified three galaxy concentrations, named NW1, NW2 and NW3, as well as two new clusters called CW1 and CW2, that could help explain the mystery behind the Great Attractor.
Now, exactly how do these new galaxies affect the Great Attractor? The researchers are not sure yet. We will just have to wait and see what they come up with after they complete further data analysis.