Most detailed Hubble image ever captures 265,000 galaxies across the cosmos
The Hubble Space Telescope has a knack for making us feel incredibly small, peering ever deeper into space and revealing the cosmos in unprecedented detail. The latest such image, named the Hubble Legacy Field, is a mosaic of thousands of exposures over the years and constitutes the largest and most comprehensive image ever put together by the Hubble science team.
The image contains a whopping 265,000 galaxies, but don't bother trying to spot them all – the faintest of them are far too dim for the human eye to see. These galaxies are the farthest from Earth at a mind-blowing distance of 13.3 billion light-years, meaning the telescope has picked them up as they appeared soon after the beginning of the universe itself.
As its name suggests, the Hubble Legacy Field was created from 16 years' worth of data, stitching together almost 7,500 individual images. It captures the cosmos in a wide range of wavelengths of light, from ultraviolet to near-infrared, and uses data from 31 different Hubble programs.
"Now that we have gone wider than in previous surveys, we are harvesting many more distant galaxies in the largest such dataset ever produced by Hubble," says Garth Illingworth, lead researcher of the team. "This one image contains the full history of the growth of galaxies in the universe, from their time as 'infants' to when they grew into fully-fledged 'adults'."
As wide as the image is, the Hubble Legacy Field still only encompasses an incredibly small patch of sky – just short of the width of the full Moon. The team is currently working on other similar mosaic images of other areas of the sky, but in terms of detail nothing else will beat it until the next generation of space telescopes launches. And beat it they will.
"This will really set the stage for NASA's planned Wide Field Infrared Survey Telescope (WFIRST)," says Illingworth. "The Legacy Field is a pathfinder for WFIRST, which will capture an image that is 100 times larger than a typical Hubble photo. In just three weeks' worth of observations by WFIRST, astronomers will be able to assemble a field that is much deeper and more than twice as large as the Hubble Legacy Field."
If you want to really boggle at the scope and scale of space, the video below starts with what the Hubble Ultra Deep Field image captured in 2004, then zooms out to reveal just how much wider the new Hubble Legacy Field image really is. It's quite a ride.