hanny van arkel, galaxy zoo project, amateur astronomer discovers black hole

Armchair Astronomer Aids Researchers in Space Cloud Classification

December 10, 2008 04:30 PM
by Isabel Cowles
Scientists appear to have determined the cause of an unusual green cloud formation in a nearby galaxy, discovered last year by amateur astronomer Hanny van Arkel.

Black Hole Behind Green Cloud

Dutch schoolteacher Hanny van Arkel stumbled upon an image of a strange green cloud last summer while going through data collected by a community astronomy Web site called the Galaxy Zoo project.

According to, “Van Arkel came across an image of a huge, irregular-shaped greenish-yellowish cloud near the spiral galaxy IC2497.” The cloud was subsequently named “Hanny’s Voorwerp,” Dutch for “Hanny’s thing.”

Van Arkel joined expert astronomers from the Netherlands Institute for Radio Astronomy to explore the unusual gas cloud in greater depth; they determined that radiation from a black hole is energizing particles within Hanny’s Voorwerp, accounting for its greenish glow.

“I’m happy we are making progress,” Van Arkel said. “Apparently the more we learn about the Voorwerp, the more intriguing it becomes.”

Background: A new appraisal of the “armchair astronomer”

Van Arkel’s discovery is an example of an intriguing phenomenon, in which the public do official astronomical work. Yale University astrophysicist Kevin Schawinski and Oxford University professor Chris Lintott developed the Galaxy Zoo project, an initiative that invites the public to assist in cataloging more than one million images taken by the Sloan Digital Sky Survey telescope during the last 16 years. A brief online tutorial explains how to categorize the galaxies as spiral, elliptical or something else.

“We were overwhelmed by the response. It completely melted the server,” Schawinski told CNN, noting that most of the volunteers are not professional astronomers.  “They're just regular people who got excited about the project,” he explained.
Within a month of signing on to the project, van Arkel had discovered the unusual green cloud. Her find has caused some astronomers to rethink their opinion of amateur work. Bill Keel, professor of physics and astronomy at the University of Alabama and a Galaxy Zoo team member said, “This discovery really shows how citizen science has come of age in the Internet world.” He added, “There was a time when I spoke pejoratively of armchair astronomers. And I've gotten up at a star party and publicly apologized for that.”

Schawinski noted that the public's collective wisdom was remarkably perceptive. For example, if the majority of participants categorized a galaxy as elliptical, astronomers agreed with their assessment.

Reference: Galaxy Zoo Project


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