Astronomers Find a Black Hole in Our Cosmic Back Yard (nytimes.com) 21
Almost but not quite in time for Halloween, astronomers announced on Friday that they had discovered the closest known black hole. It is a biggie, a shell of yawning emptiness 10 times as massive as the sun, orbiting as far from its own star as the Earth is from ours. From a report: Not to worry, however: This black hole is 1,600 light-years away, in the constellation Ophiuchus; the next nearest known black hole is about 3,000 light-years away in the constellation Monoceros. What sets this new black hole apart from the 20 or so others already identified in our Milky Way galaxy, besides its proximity, is that it isn't doing anything -- not drawing the nearby star to its doom, not gravitationally consuming everything nearby. Rather, the black hole is dormant, a silent killer waiting for the currents of space to feed it.
Kareem El-Badry, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, has been searching for such hidden demons for four years. He found this black hole by scrutinizing data from the European Space Agency's GAIA spacecraft, which has been tracking with exquisite precision the positions, motions and other properties of millions of stars in the Milky Way. Dr. El-Badry and his team detected a star, virtually identical to our sun, that was jittering strangely, as if under the gravitational influence of an invisible companion.
To investigate further, the researchers commandeered the Gemini North telescope atop Mauna Kea in Hawaii, which could measure the speed and period of this wobble and thus determine the relative masses of the objects involved. The technique is identical to the process by which astronomers analyze the wobbles of stars to detect the presence of orbiting exoplanets -- except this time the quarry was far bigger. Their results and subsequent calculations were consistent with a black hole of 10 solar masses being circled by a star similar to our own. They named it Gaia BH1.
Kareem El-Badry, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, has been searching for such hidden demons for four years. He found this black hole by scrutinizing data from the European Space Agency's GAIA spacecraft, which has been tracking with exquisite precision the positions, motions and other properties of millions of stars in the Milky Way. Dr. El-Badry and his team detected a star, virtually identical to our sun, that was jittering strangely, as if under the gravitational influence of an invisible companion.
To investigate further, the researchers commandeered the Gemini North telescope atop Mauna Kea in Hawaii, which could measure the speed and period of this wobble and thus determine the relative masses of the objects involved. The technique is identical to the process by which astronomers analyze the wobbles of stars to detect the presence of orbiting exoplanets -- except this time the quarry was far bigger. Their results and subsequent calculations were consistent with a black hole of 10 solar masses being circled by a star similar to our own. They named it Gaia BH1.
Its own star? (Score:2)
Black holes usually WERE a star, thus to have another star nearby it would have been a binary system. Not something I would describe as "its own star", anyway.
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poor editing. the article makes pretty clear that it is a binary system, and a tricky one: they don't understand how the companion could have survived the now black hole being a supergiant. i guess this points at alternative ways of black hole formation.
Re: Its own star? (Score:1)
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I thought black holes were more massive than stars
Black holes are dead stars, so it follows that a living star can be as large as a black hole. I didn't read the article but the summary explicitly says that it's not "eating local" so there's no reason it would have significantly more mass than when it first collapsed.
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in lay mans terms, black holes are formed by stars effectively imploding to a smaller size. So take out sun but make it the size of the earth. The total gravity exerted to options in our solar system would be the same, but things close enough, including light, would not escape the event horizon. Thus black hole.
The explosion needs to have enough energy with enough mass being left behind. And of course assuming the explosion of the star didn't cause orbits to change.
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in lay mans terms, black holes are formed by stars effectively imploding to a smaller size. So take out sun but make it the size of the earth.
You're off by a factor of more than 2,000. A black hole with the mass of the Sun would have a radius of under 2 miles. [astronomy.com]
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black hole or star, any two orbiting objects always do it around a barycenter, a point somewhere between the center of both objects, depending on their relative mass. this point is never exactly in the center of any object, even if one object is much more massive than the other, the barycenter will be slightly displaced causing the more massive object to wobble while the other orbits around. if both objects are similar mass the barycenter would be roughly halfway between the two objects and both would have
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Umm, no.
The largest black holes ("supermassive black holes", SMBHs) in the cores of galaxies and quasars can be billions of times the mass of the Sun, while the largest stars are at most hundreds of times the mass of the Sun (and lose mass quite rapidly - which makes the measurements necessary for weighing them difficult). Asking "How SMBHs gained all their mass" is a good way to start a fight at an astrophysics confe
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Everything you said is true, but it'd be next to impossible to detect a stellar mass black hole without a companion stare so pretty much all of them we know about are part of a binary system. It sort of becomes a mandatory aspect of them even though there are plenty of solitary black holes in existence we just don't know about them.
"Commandeered" or "requested time on" Gemini North (Score:2)
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We can do without the over-dramatization. I'm fairly sure that these researchers didn't sneak into the telescope facility, overpower the guards, and point it towards their target.
And yet I can guarantee, in the Hollywood version, this will be PRECISELY how it went down.
NYTimes is wrong again! (Score:3, Funny)
Re: NYTimes is wrong again! (Score:1)
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Back yard (Score:2)
You kids put that down and come inside for dinner. And wash your hands first. That thing looks dirty.
Yeah, "close" (Score:3)
This is how "close" this black hole is. If you made a scale model of the solar system in which our sun was represented by a small pea 5mm (less than 1/5th an inch) in diameter. The Earth would be the size of a grain of talcum powder about two meters away. And the scale model of this black hole would need to be put on Mars. At its closest point to Earth, Mars's orbit lines up almost exactly with the 54.3 million kilometers away you'd have to put the scale model of the black hole (which would be considerably smaller in volume than the pea-sized Sun).
“Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.” - Douglas Adams
Not a "Biggie" (Score:2)
Orbiting a star at Earth's distance? (Score:1)
This looks like proof of intelligent life — clearly an advanced civilisation in the goldilocks zone set up a physics experiment that went horribly, horribly awry.
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Just kidding! Honestly, the black home is probably just the crash site of a singularity-powered starship that tried to reboot its magnetic field isolation controller on a tropical moon somewhere.