There's a mysterious force pulling the Milky Way galaxy towards it at 2 million km per hour and scientists may have finally found out why.
An international team of researchers led by the International Center for Radio Astronomy Research at the University of Western Australia (UWA) have discovered 883 galaxies hidden in the nearby universe, 250 million light-years from earth, behind the Milky Way, a third of which had never been seen before.
"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," University of Cape Town professor of Astronomy, Renee Kraan-Korteweg said in a statement on Wednesday.
The study's lead author, UWA professor of radio astronomy Lister Staveley-Smith said this discovery may help explain the "Great Attractor" region that is pulling the Milky Way and several other galaxies towards it with the gravitational force equivalent to a million, billion Suns.
"We don't actually understand what's causing this gravitational acceleration on the Milky Way or where it's coming from," Staveley-Smith said.
"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 per hour."
Astronomers have been trying to map the galaxies hidden in the so-called Zone of Avoidance, a part of the sky obscured by the Milky Way, since major deviations in the rate of expansion of the universe in this area were detected during the 1970s and 1980s.
By using Australia's chief scientific body CSIRO's Parks radio telescope, located in the middle of a sheep paddock in central New South Wales state and used in NASA's Apollo missions, the team were able to see through the stars and dust of the Milky Way into Zone of Avoidance.
"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," Kraan-Korteweg said.
The Parks radio receiver, known in Australia as The Dish, has recently been fitted with innovative technologies, such as a 21-cm multi-beam receiver, that allow scientists to map the sky 13 times faster that they could before.
The study, published on Wednesday in the Astronomical Journal, involved researchers from Australia, South Africa, the United States and the Netherlands.
