Astronomers Find Closest Black Hole to Earth
European astronomers have found the closest black hole to Earth yet. It's so near that the two stars dancing with it can be seen by the naked eye.
The black hole is about 1,000 light-years away, and each light-year is 9.5 trillion kilometers. The previous closest black hole is probably about three times further, about 3,200 light-years, said European Southern Observatory astronomer Thomas Rivinius.
The discovery of a closer black hole, which is in the constellation Telescopium in the Southern Hemisphere, suggests that there are more of them out there. Astronomers believe there may be between 100 million to 1 billion of them in the Milky Way.
*them=black hole
The trouble is we can't see them. Nothing, not even light, escapes a black hole's gravity. Usually, scientists can only spot them when they're consuming parts of a star or something else that has fallen into them.
Astronomers think most black holes, including this newly discovered one, don't have anything close enough to swallow, so they go undetected.
Astronomers found this one because of the unusual orbit of a star. The new black hole is part of a three-star system called HR6819. Two of the remaining stars aren't close enough to be sucked in, but the inner star's orbit is warped.
*발음주의 war(전쟁) 에다 -ped 붙였다고 생각하기
Using a telescope in Chile, they confirmed that there was something about four or five times the mass of our sun pulling on the inner star. It could only be a black hole, they concluded.
Outside astronomers said that makes sense.
"It will motivate additional searches among bright, relatively nearby stars," said Ohio State University astronomer Todd Thompson, who wasn't part of the research.
This black hole is tiny, maybe 40 kilometers in diameter.
The HR6819 system has young, hot stars compared to our 4.6 billion-year-old sun. They may be 140 million years old, but at 15,000 degrees Celsius they are three times hotter than the sun, Rivinius said.
About 15 million years ago, one of those stars got too big and too hot and went supernova, turning into the black hole, he said.
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observatory /əbˈzərvəˌtoʊriː/
a building from which the scientists study the sky
Tonight the observatory is open until midnight.
constellation /ˌkɑːnstəˈleɪʃn/
a group of stars forming a shape in the sky
My dad taught me how to find the Little Bear constellation.
Vocabulary
undetected /ˌʌndɪˈtektɪd/
not discovered or noticed
They broke into the palace completely undetected.
*break into
orbit /ˈɔːrbɪt/
the path that is taken by an object moving around a planet, sun, etc.
The spacecraft has gone into orbit around Saturn.
warped /wɔːrpt/
twisted or bent out of shape
The timber is all warped from being left in the rain.
space warped
supernova /ˈsuːpərnəʊvə/
the extremely large and bright explosion of star
Supernovas are caused by changes in the core of a star
super nova
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