STEVE INSKEEP, host:
Even if some people ask how their tuition and tax money seems to have dropped into a black hole, astronomers have reported they discovered the birth of an actual black hole, possibly. This could help scientists understand how black holes form and devolve.
NPR's Richard Harris says the story started in the backyard in Western Maryland.
RICHARD HARRIS: On the evening of April 15th, 1979, while countless Americans were rushing to finish their tax returns, Gus Johnson was on a cosmic pursuit in his backyard, touring one little corner of the heavens.
Mr. GUS JOHNSON: And I decided to share the tour using my eight-inch telescope and the pastor of my church.
HARRIS: The two men gazed up at a galaxy called M100 in the constellation Coma Berenices.
Mr. JOHNSON: For some reason, I don't know why, this little star in M100 caught my attention.
HARRIS: On a hunch, he pulled up a detailed chart of all the stars in this part of the sky.
Mr. JOHNSON: And it wasn't on it.
HARRIS: He had discovered an uncharted star. In fact, the star only visible because it was in the throes of a violent explosion - a supernova.
Professional astronomers rolled out their giant telescopes and confirmed the discovery, now known as supernova 1979C. Astronomers say the star that exploded was just 50 million light years away, and about 20 times the mass of our sun.
And Abraham Loeb at the Harvard Smithsonian Center for Astrophysics says when a star that size explodes, it can end up in one of two forms.
Professor ABRAHAM LOEB (Harvard Smithsonian Center for Astrophysics): Either it makes a neutron star, which is the densest form of matter that we know about. It has the density similar to that of an atomic nucleus and a size comparable to that of a big city, or it ends up in a black hole, which is an object to which you can get in, but can never get out of.
HARRIS: So fast-forward to today. To figure out what befell the 1979 supernova, Loeb and his colleagues turned NASA's Chandra X-ray Observatory to that corner of the sky. And they now conclude that the supernova most likely ended up as a black hole.
Prof. LOEB: If our interpretation is correct - and indeed, Supernova 1979C ended up as a black hole - then, of course, it's the first time that we are seeing a black hole being born in a normal supernova.
HARRIS: Loeb is quick to add that they see black holes being born all the time in abnormal supernovas - that is, vastly larger cosmic explosions from billions of light years away.
Now, it's still possible this supernova did end up as a neutron star.
Alex Filippenko from UC-Berkeley says in that event, X-rays they witness could be coming from a huge cloud of glowing gas called a pulsar wind nebula, like the picturesque crab nebula.
Professor ALEX FILIPPENKO (UC-Berkeley): So, I'm pretty excited about this discovery, regardless of whether it turns out to be a young black hole or a pulsar wind nebula.
HARRIS: NASA announced the discovery at a news conference Monday.
Richard Harris, NPR News.
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