Sen— - Its already revealed one, and NASA's Wide-field Infrared Survey Explorer (WISE) is expected to reveal many more galaxy clusters. They are the rarest and largest of galaxy groupings, with thousands of galaxies bound together by gravity, and can be the hardest for astronomers to find.
Galaxy clusters are created by matter formed in the very early universe, and grew rapidly by a process called inflation. Knowing more about them is hugely important to scientists. "By uncovering the most massive of galaxy clusters billions of light-years away with WISE, we can test theories of the Universe's early inflation period" says Anthony Gonzalez of University of Florida, Gainesville, who led the research.
For cosmologists this is significant, because one of the big questions they are trying to answer is how did the first bumps and wiggles in the distribution of matter in our Universe rapidly evolve into the massive structures of galaxies we see today.
Using data from WISE, Gonzalez and his team were able to locate a galaxy cluster 7 billion light years away - which is about half way back in time to the Big Bang - and a hundred times more massive than the Milky Way. They are now hoping to use the information to find more clusters.
Normally galaxy clusters from the early Universe are difficult to find as they are so far away and not very many had formed by then. In addition to those problems, they are hard to see using visible telescopes because due to the expansion of space, the light which left them has become stretched into longer infrared wavelengths. But WISE can be used to help find these as it scans the whole sky in infrared light.
The NASA mission was launched at the end of 2009 and spent over a year imaging the night sky at infrared wavelengths, completing two scans of the sky. The team have since combined all this data, enabling astronomers to study everything from nearby stars to distant galaxies. These next-generation all-sky images are part of a new project called 'AllWISE', with more sensitive observations, which will be released late next year.
The hope is, that by using the new improved AllWISE data, astronomers will now be able to find more massive galaxy clusters from our early Universe. These clusters would have come together even further back in time and are thousands of times bigger then our own galaxy.
The information is also planned to help other projects such as searching for tiny cool stars, with masses as low as planets.