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Scientists Compile 'Census Of The Galaxies' Using Power Of The Crowd

  • Richard Solash

Astronomers have sought the aid of enthusiastic amateurs to help them take on the Herculean task of studying the cosmos.

Astronomers have sought the aid of enthusiastic amateurs to help them take on the Herculean task of studying the cosmos.

Cutting-edge instruments allow us to peer deep into time and space. But back on Earth, there are still just 24 hours in a day. That's the conundrum researchers have increasingly faced in recent years as the quantity of images returned by telescopes has outpaced attempts at organizing them.

But an international group of scientists is now tackling that problem by harnessing people power, plus the Internet, to help them take on the enormity of the universe.

The result is "Galaxy Zoo," a project determined to catalog the skies. It has just completed its second groundbreaking phase.

"Galaxies tend to come in two main morphologies, or shapes: ellipticals or spirals," Lucy Fortson, a professor of physics and astronomy at the University of Minnesota and one of the project's leaders, told RFE/RL. "The complexity of those shapes makes it very difficult for machine algorithms or computers to be able to tell the difference. The best machine algorithm that we have to tell the difference between these shapes is actually the human brain. There was a graduate student from Oxford [who was working on this] and his supervisor, and they sat in a pub and thought, 'You know, if we just put this up on the web, do you think people would come and classify the galaxies?'"

The answer was a resounding "yes." The first phase of the project, completed in 2009, asked interested volunteers from around the world to help classify nearly 1 million galaxies from the near universe into basic shapes. No scientific knowledge was required. Eyes, interest, and the ability to log on to galaxyzoo.org were all that was needed.

Fascinating And Beguiling

It was such a success, Fortson said, that participants asked the organizers to give them more work. The scientists were happy to oblige. They have now published the findings of "Galaxy Zoo 2," the culmination of some 16 million classifications by more than 83,000 enthusiasts.

The project took 300,000 galaxies with the clearest images and asked volunteers not only to describe their basic shape but also provide more detailed descriptions: If the galaxy has spirals, how many spiral "arms" are present? Does the galaxy have "galactic bars" -- long, extended features that represent a concentration of stars? Does the galaxy appear to be merging with another one?

The classifications were registered between February 2009 and April 2010.

Scientists working on the project say that the resulting catalog is 10 times larger than any previous effort of its kind. They estimate that it represents what would be about 30 years of full-time work by a single researcher.

The data should help scientists chip away at questions that have long fascinated and beguiled people.

"One of the big questions that humans are trying to understand is, 'How did our universe evolve?' "How did we get here?'" said Fortson. "One aspect of that is understanding how galaxies came to be. We know that a galaxy's personality, if you will, is shaped by its history -- and its history is written in its morphology."

Scientific Rigor

Galaxy Zoo's use of crowdsourcing -- or the reliance on large groups of respondents, usually over the Internet, to obtain data or information -- is not a first in scientific attempts to learn about the universe.

For years, alien-seekers have used computer programs provided by several universities and research projects to help scour the universe's radio waves for signs of intelligence.

Scientific rigor does play a part in projects based on crowdsourcing. In Galaxy Zoo 2, each galaxy was classified an average of 40 to 45 times to ensure accuracy. Fortson said her team used "strict methods and formulas" to weed out classifications from those participants "who may not have been paying the best attention."

The next step is to task volunteers with classifying images provided by the Hubble telescope from the dawn of the universe.

"I liken it to taking a census," said Fortson. "We've just taken a census of now: We've gone around and we've interviewed all these galaxies and we've figured out the diversity -- the rich diversity -- of galaxies in our nearby universe. Now we want to go back in time and take a census of galaxies at the beginning of their formation. Comparing those two censuses can tell us a lot about how the population of galaxies has evolved."
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