Space fans find new breed of galaxy

 

An army of space fans have made a major discovery about the universe by taking up an addictive online computer challenge called Galaxy Zoo.

Hundreds of thousands of volunteers – ordinary members of the public – signed up for the task of identifying more than a million newly photographed galaxies.

And the amateurs have surprised professional astronomers by discovering a new type of galaxy that had previously gone completely unrecognised.

Experts say the newly discovered objects – red spirals – are a “missing link” in their understanding of how these vast cities of billions of stars evolve.

Their results, which reveal a swathe of such galaxies spread through the universe, are independently confirmed today by a second British team which used the Hubble space telescope.

Amazingly, the cosmic breakthrough was made by enthusiasts from all walks of life who signed up to Galaxy Zoo, a UK-led project, last year. They call themselves Zooites and have formed a close-knit community.

Galaxy Zoo was dreamed up by Chris Lintott, co-presenter with Sir Patrick Moore of The Sky At Night on BBC TV.

Chris, an astrophysicist at Oxford University told Skymania News: “We had more than a million galaxies to analyse and we quickly realised that was too many for one or two researchers to handle.

“I gave a few talks to promote the Galaxy Zoo idea last year and interest was astonishing. Within days of launching our website people were checking out 75,000 galaxies an hour!

“It must be the equivalent to one of the most powerful computers in the world to have all those human brains wired together. The success of the project has exceeded our wildest dreams.”

The Zooites were asked to click through a selection of more than a million distant galaxies newly recorded by a robotic scan of the heavens called the Sloan Digital Sky Survey. For many of these galaxies when the volunteers checked them out, it was the first time they had ever been viewed by human eyes.

The volunteers were asked to note if the blobs of galaxies were spiral or an elliptical shape like a rugby ball. If they were spiral, they had to judge if they were wound clockwise or anti-clockwise.

But an unexpected result was to find so many spirals with a red hue. Professional astronomers say they are a newly identified population of galaxies which have been stripped of the gas needed to form new stars. They get their colour from a shroud of dust that has spread around the stars.

Spiral galaxies usually appear a bluish-white because they are vigorously giving birth to new stars like the sun. Elliptical galaxies are a mass of mostly old, dead red stars crowded together.

Chris added: “These red spiral galaxies had been lurking in the data and no-one had spotted them. They were staring us in the face. Now we know that a third of spirals around the edges of some clusters of galaxies are red.

“Before, every astronomer knew that spiral galaxies were full of young stars and were blue. It turns out they were wrong!

“Old elliptical galaxies have undergone violent events. But it seems these red galaxies are being gently strangled. It is like the difference between squeezing someone’s neck gently and ripping their head off.”

Galaxy Zoo users often say the challenge is like a drug because you always want to check out “just one more galaxy” before you stop.

One keen Zooite who runs the Galaxy Zoo forum is Alice Sheppard, 26, from Pembrokeshire. She said: “Galaxy Zoo has taken over my life, because it’s the most interesting thing I’ve ever done and feels like the truest and the most worthwhile.

“The fact that ordinary people can make such a discovery is tremendously exciting. It is not always seen as cool or fashionable to be interested in science but I think people are much more curious about the universe than they admit.”

The independent galaxy survey, called STAGES, that confirmed the Galaxy Zoo work was led by Meghan Gray, of the University of Nottingham. She said: “Our two projects have approached the problem from very different directions. It is gratifying to see that we each provide independent pieces of the puzzle pointing to the same conclusion.”

The work of both teams – professional and enthusiastic Zooites – will be published in the Monthly Notices of the Royal Astronomical Society.

Picture: The photos show three types of galaxy, blue spiral, red spiral and elliptical as ued by the Zooites (top row) and STAGES team (bottom row). (Credits: Galaxy Zoo/SDDS and Hubble/STAGES team).

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