NASA’s Hubble telescope has been drafted in to solve the riddle of a mysterious green object that resembles a giant space frog.  The cosmic Kermit appears to be swimming through space in the direction of a spiral galaxy containing hundreds of billions of stars and labelled IC 2497.

Hubble photo of Hanny’s Voorwerp (NASA/ESA)

It was first spotted in 2007 as a ghostly glow by a Dutch schoolteacher, Hanny van Arkel, while she was taking part in an online challenge to classify different types of galaxies.

It was dubbed Hanny’s Voorwerp – Dutch for Hanny’s Object – and became a standing mystery in the Galaxy Zoo project that was begun by scientists at Oxford in the UK.

Now Hubble’s powerful vision from orbit has identified the gowing cloud of gas forming the frog as a celestial incubator where new stars are being born.

They believe the gas cloud is glowing because it was illuminated by a brilliant searchlight from an energetic object called a quasar at the centre of the galaxy which lies 650 million light-years from Earth.

The quasar, which was powered by a black hole, is thought to have switched itself off less than 200,000 years ago. But the glow from its light beam striking Hanny’s Object can still be seen as a light echo.

Hubble also shows that a flow of gas from the core of the galaxy is interacting with the gas cloud. Astronomer Bill Keel of the University of Alabama, who led the Hubble investigation, revealed the results today at the American Astronomical Society meeting in Seattle, USA.

Hanny, who was given time off school to be special guest at the Seattle conference, says she was inspired to take part in the citizen science project Galaxy Zoo by a posting on Queen guitarist and astronomer Brian May’s blog.

She said on her own blog: “I never expected I’d see something in a picture that turns out to be so interesting that newspapers say I ‘discovered’ something.”

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