Astronomers may have found youngest black hole isn't really a great title for the article. We witnessed a supernova in 1979 in a nearby galaxy and have been observing it since. "The star that exploded was right on the edge of being massive enough to create a black hole; the total mass of the star was about 20 times the mass of the Sun, with a core of just about 3 solar masses. The question is, was the star big enough to create a black hole, or would the core collapse to form an incredibly dense neutron star?"
"What astronomers have found is that the X-rays from SN1979c have been steady in brightness over observations from 1995 – 2007. This is very strong evidence that the star’s core did indeed collapse into a black hole."
"This is an important result for many reasons. One is that we’ve had the math to calculate the borderline mass between a neuron star and black hole for decades, but it’s nice to see the Universe agrees with our calculations. Whether it turns out to be a neutron star or a black hole, the numbers for the mass that astrophysicists have crunched are pretty close; the very fact that this is a borderline object means our math is solid!
Second, we know almost the precise moment this object was born. That helps nail down a lot of the physics. Black holes and neutron stars are objects of immense power, and when they are this young they can change rapidly on a cosmic scale; observations over just a few decades can show large differences in the brightness or energy of the emitted radiation. Knowing the date of birth to within a few days anchors the calculations and models used by scientists to explain the phenomena."
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