Hanny's Voorwerp

StarDate: March 12, 2009

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The universe still holds plenty of mysteries. And you don't have to be a professional astronomer to discover them.

Consider a strange blob of light known as Hanny's Voorwerp. It was discovered by Hanny van Arkel, a teacher in the Netherlands, who was perusing some pictures of galaxies as part of a project called the Galaxy Zoo. Volunteers log on to a web site to help astronomers classify galaxies.

One of the pictures showed a bright blue blob near a spiral galaxy. Van Arkel asked what it was, but the astronomers didn't know. They called it a voorwerp -- the Dutch word for "object" -- and began studying it.

Using several telescopes on the ground and in space, they discovered that the object is related to the galaxy -- they're separated by just 60,000 light-years. The astronomers also found that the object is a glowing cloud of gas and dust. But it glows differently from most celestial clouds.

After months of study, the astronomers concluded that the cloud was lit up by a giant black hole in the heart of the galaxy. A disk of superhot gas and dust surrounded the black hole, producing enormous amounts of energy -- a quasar. Some of the energy lit up part of a cloud of gas and dust that surrounds the galaxy.

The quasar itself has probably shut down. But because the cloud is so far away from it, the last of the quasar's light is still streaming toward it. So Hanny's Voorwerp is an echo of a quasar that stopped shining thousands of years ago.

Script by Damond Benningfield, Copyright 2009

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