The Hubble Space Telescope just revealed the deepest view of the universe ever seen – and it relied on a traffic jam of galaxies to do it.
The new image (right) is the first in a series of "Frontier Field" images, which take advantage of an effect called gravitational lensing to peer further into the universe than ever before. Gravitational lensing happens when huge collections of matter – such as those found in galaxy clusters – warp the space-time around them so that the light from objects behind the clusters takes a curved path. These galaxy clusters can act as cosmic magnifying glasses, bringing objects into focus that would otherwise be too faint and distant to see.
Hubble has been taking advantage of this effect since its first "Deep Field" image in 1996, which revealed thousands of galaxies in an apparently empty square of space.
Pandora's Cluster
Now, astronomers have singled out six galaxy clusters as the best natural lenses they could find for the Frontier Field survey, which will run for three years. This first image is of a cluster called Abell 2744 (pictured), also known as Pandora's Cluster. It is thought to be the site of a great galactic pile-up of at least four separate galaxy clusters.
The image, which took 50 hours of exposure time to create, reveals the curved, warped images of thousands of galaxies, some of which are further than 12 billion light-years away. This is, in effect, a picture taken when the cosmos was just a billion years or so from the big bang.
Astronomers led by Jennifer Lotz of the Space Telescope Science Institute (STScI) in Baltimore, Maryland, presented the image at a meeting of the American Astronomical Society in Maryland this week.
The survey will help astronomers determine when galaxies first formed in the universe. They can also help trace the amounts of invisible dark matter in the clusters, possibly giving a clue to how this mysterious substance behaves.
Journal reference: Submitted to Astrophysical Journal, arxiv.org/abs/1311.7670
If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.
