Hanny's Voorwerp facts for kids
Hanny's Voorwerp is a very unusual and mysterious object in space. Its name is Dutch for "Hanny's Object." It was discovered in 2007 by a Dutch schoolteacher named Hanny van Arkel. She found it while helping scientists as a volunteer for the Galaxy Zoo project.
This amazing discovery was made through citizen science, where regular people can help with real scientific research. On star maps, Hanny's Voorwerp looks like a bright green blob floating next to a spiral galaxy called IC 2497. Scientists believe it is a rare thing called a light echo. It's like a "ghost" of a very bright object called a quasar that has since disappeared.
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What is Hanny's Voorwerp?
Hanny's Voorwerp is huge, about the size of a small galaxy. It also has a giant hole in its center that is more than 16,000 light years wide.
Pictures from the Hubble Space Telescope show the Voorwerp glowing with a bright green light. This color comes from superheated oxygen gas. The object is about 650 million light-years away from Earth, the same distance as its neighboring galaxy, IC 2497.
In one part of the Voorwerp, new stars are being born. This is happening in the area that faces the galaxy IC 2497. Scientists think that a stream of gas flowing out from the galaxy is pushing on the gas in the Voorwerp. This push is causing the gas to clump together and form new stars. The youngest of these stars are several million years old.
The Mystery of the Missing Light
The biggest puzzle about Hanny's Voorwerp is why it's glowing so brightly. The galaxy next to it, IC 2497, isn't powerful enough to light it up. This led scientists to come up with an exciting theory.
A Ghost of a Quasar
The main idea is that Hanny's Voorwerp is a giant cloud of gas that is being lit up by the memory of a quasar. A quasar is an extremely bright and powerful object powered by a supermassive black hole at the center of a galaxy.
Scientists think that about 200,000 years ago, the galaxy IC 2497 had a very active quasar at its core. The intense light and energy from this quasar blasted out into space and hit the nearby gas cloud, causing it to glow.
Then, the quasar "turned off" or faded away. But because the Voorwerp is thousands of light-years away from the galaxy, the light from the quasar is still traveling to it. So, we see the Voorwerp glowing brightly, even though the quasar that lit it up is now gone. It's a "light echo," like seeing a flash of lightning and hearing the thunder much later.
Other Clues
Another idea is that a powerful jet of energy from the galaxy's black hole is also helping to light up the gas. Using the Chandra X-ray Observatory, scientists found evidence of a giant bubble of hot gas around the galaxy's center. This bubble was likely created by the old quasar, giving more support to the light echo theory.
Finding More "Little Objects"
After the discovery of Hanny's Voorwerp, scientists and Galaxy Zoo volunteers wondered if there were more objects like it. They searched through star surveys and found 19 more galaxies with similar glowing clouds.
They nicknamed these clouds Voorwerpjes, which is Dutch for "little objects." Finding these Voorwerpjes proved that Hanny's Object was not alone. These objects help scientists study the history of galaxies and learn how quasars can suddenly turn on and off.
One of the most famous Voorwerpjes is called the Teacup Galaxy. It has giant "bubbles" of glowing gas extending out from it. One bubble is visible in normal light, while another can only be seen with radio telescopes. These discoveries show that the universe is full of amazing and surprising things, sometimes found by curious people right here on Earth.
Gallery of Other Voorwerpjes
Here are some other amazing "Voorwerpjes" found by scientists and volunteers.
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A Hubble Space Telescope image of the Teacup Galaxy, a famous Voorwerpje.
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The Teacup Galaxy showing glowing bubbles seen by Hubble (blue) and the Very Large Array radio telescope (orange).
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The Voorwerpje glowing around the galaxy NGC 5972.
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The Voorwerpje around the galaxy SDSS 1510+07.
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The Voorwerpje around the galaxy UGC 7342.
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The Voorwerpje around the galaxy NGC 5252.
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The Voorwerpje around the galaxy Markarian 1498.
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The Voorwerpje around the galaxy UGC 11185.
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The Voorwerpje around the galaxy SDSS 2201+11.
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The galaxy NGC 7252, which also has a Voorwerpje on its outskirts.
See also
