LEDA 2073461 and SDSS J115331.86+360024.2 look like they’re interacting, but they are actually separated by millions of light-years.
This Hubble image shows two overlapping spiral galaxies: LEDA 2073461 and SDSS J115331.86+360024.2. Image credit: NASA / ESA / Hubble / W. Keel.
LEDA 2073461 and SDSS J115331.86+360024.2 lie approximately one billion light-years away from Earth in the constellation of Ursa Major.
Despite appearing to collide in this image from the NASA/ESA Hubble Space Telescope, the alignment of the two galaxies is likely just by chance.
The image is one of many Hubble observations delving into highlights of the Galaxy Zoo, the world’s best-known online citizen science project.
Originally established in 2007, this project and its successors crowdsource galaxy classifications from a pool of hundreds of thousands of volunteers.
“It all started back in July 2007, with a data set made up of a million galaxies imaged by the Sloan Digital Sky Survey, who still provide some of the images in the site today,” said the astronomers behind the Galaxy Zoo.
“With so many galaxies, we assumed it would take years for visitors to the site to work through them all, but within 24 hours of launch we were stunned to be receiving almost 70,000 classifications an hour.”
“In the end, more than 50 million classifications were received by the project during its first year, contributed by more than 150,000 people.”
Over the course of the Galaxy Zoo project, the volunteers discovered a menagerie of weird and wonderful galaxies such as unusual three-armed spiral galaxies and colliding ring galaxies.
“For more than a decade, we’ve asked volunteers to help us explore galaxies near and far, sampling a fraction of the roughly one hundred billion that are scattered throughout the observable Universe,” the astronomers explained.
“Each one of the systems, containing billions of stars, has had a unique life, interacting with its surroundings and with other galaxies in many different ways; the aim of the Galaxy Zoo team is to try and understand these processes, and to work out what galaxies can tell us about the past, present and future of the Universe as a whole.”
“Our strategy is based on the remarkable fact that you can tell a lot about a galaxy just from its shape,” they added.
“Find a system with spiral arms, for example, and normally you’ll know that you’re looking at a rotating disk of stars, dust and gas with plenty of fuel for future star formation.”
“Find one of the big balls of stars we call ellipticals, however, and you’re probably looking at a more mature system, one which long ago finished forming stars.”
“The galaxies’ histories are also revealed; that elliptical is likely to be the product of a head-on collision between two smaller galaxies, and smaller features such as warped disks, large bulges or long streams of stars bear testament to the complexity of these galaxies’ lives.”
