4 New Galaxy Clusters Found: Scientists Say 2000 More Galaxies Waiting To Be Discovered
The discovery of four unknown galaxy clusters, which are over 10 billion light years from Earth has provided an opportunity for researchers to (almost) experience time travel. Considering that the light from the farthest of these galaxies would have taken over 10 billion years to reach the Earth, the fact that researchers are now able to see how the clusters looked when the universe was just 3 billion years old is pretty amazying.
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"Although we're able to see individual galaxies that go further back in time, up to now, the most distant clusters found by astronomers date back to when the universe was 4.5 billion years old. This equates to around nine billion light years away. Our new approach has already found a cluster in existence much earlier than that, and we believe it has the potential to go even further", said lead researcher Dr. David Clements, from the Department of Physics at Imperial College in London, according to a press release released Wednesday.
Using a new method, an international team of astronomers used data from two European Space Agency satellites, Plank and Herschel, to identify new and distant galaxy clusters. Scientists believe that up to 2000 new clusters can be identified using this new approach.
Each galaxy cluster is an aggregation of hundreds and thousands of galaxies bound together by gravity. This makes them among the most massive objects in the universe. Galaxies are classified into two types based on the number of stars and the amount of dust and gas. Galaxies such as our own, the Milky Way, which has a lesser number of stars and large amounts of dust and gas are called spiral galaxies while galaxies with many stars and less dust and gas are called Elliptical galaxies.
The clusters that are further away from the earth can be seen from such great distances because they contain galaxies in which huge amounts of dust and gas are being converted into stars. This conversion emits light, which is picked up by satellite surveys.
"What we believe we are seeing in these distant clusters are giant elliptical galaxies in the process of being formed," says Dr. Clements.
The Spectral and Photometric Imaging Receiver (SPIRE) instrument recorded the observations as part of Herschel Multitiered Extragalactic Survey (HerMES). "The fantastic thing about HerschelSPIRE is that we are able to scan very large areas of the sky with sufficient sensitivity and image sharpness that we can find these rare and exotic things. This result from Dr. Clements is exactly the kind of thing we were hoping to find with the HerMES survey", said Seb Oliver, Head of the HerMESsurvey.
Source: David Clements, F Braglia, A. Hyde et al. HerMES: Clusters of Dusty Galaxies uncovered by Herschel and Planck. Monthly Notices of the Royal Astronomical Societ. 2014.
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