"Goldilocks" Black Hole Is Neither Too Big Nor Too Small

By Eliza Strickland | July 6, 2009 7:03 am

medium black holeAstronomers believe they’ve found something never before detected in the universe: a black hole of intermediate size. And while that may not sound thrilling to the layman, researchers are thrilled by the discovery of the so-called “Hyper-Luminous X-ray Source 1,” which is poised at the edge of galaxy ESO 243-49. Astronomers are excited because they’ve seen plenty of small black holes and large black holes, but experts had questioned whether a medium-sized variety could exist. These middleweights, at about 500 times the mass of the sun, could represent a missing link between common stellar black holes, created by the death of a single star, and the supermassive variety that can pack the mass of millions or even billions of suns [SPACE.com].

Astronomers explain that small black holes, between three and 20 times the mass of the sun, are created when big stars collapse and leave behind a gravitational pull strong enough to block nearby light rays. Researchers have speculated that super-massive black holes result from the successive fusion of many smaller black holes. But without finding evidence of a medium-size hole, it was a tough theory to prove [Wired.com]. Supermassive black holes are of particular interest because they lurk at the hearts of most galaxies, and may play an important role in galaxy formation.

The new findings, reported in Nature, are based on blasts of X-rays detected from the edge of that distant galaxy, which is situated about 290 million light years away. Even though a black hole’s gravitational pull precludes the escape of radiation from its grasp, emissions, in this case x-rays, from the material falling rapidly into a black hole can reveal its existence [Scientific American]. The amount and the pattern of that radiation is consistent with a black hole about 500 times the size of our sun, though researchers say they haven’t yet proved beyond a shadow of a doubt that a black hole is the source of those X-rays.

But even if researchers do on to prove that they’re looking at a Goldilocks black hole, more questions will remain. “If they exist, it’s not at all clear where they came from,” [comments astronomer] Christopher Reynolds…. It’s possible that small black holes that formed within a densely packed stellar cluster could merge into a midsize variety. Or, intermediate-mass black holes could be leftovers from the very earliest stars in the universe, which scientists think were much larger than today’s versions [ScienceNOWDaily News].

Related Content:
80beats: We Knew Black Holes Were Massive. Now Double That.
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80beats: Two Stars Are Born Near the Perilous Edge of a Black Hole
80beats: Confirmed: Monstrous Black Hole Lurks in Our Galaxy’s Center
80beats: Researchers Look Into a Black Hole (But Does The Black Hole Look Back?)

Image: Heidi Sagerud

CATEGORIZED UNDER: Physics & Math, Space
  • http://clubneko.net Nick

    “Astronomers are excited because they’ve seen plenty of small black holes and large black holes, but experts had questioned whether a medium-sized variety could exist.”

    Why do experts say some of the dumbest things? I mean, seriously. “Plenty of small ones, plenty of large ones…. but we’ve never seen the medium sized ones so obviously they may not exist.”

    I mean, we know black holes consume more matter that falls into them and grow larger – it’s not like the supermassive ones at the center of galaxies just popped up and said “I’m going to be the densest thing ever made today! Yesterday I was just some dust.” We’ve seen small ones. There MUST be something in the middle. They’re not quanta.

    I agree we need empirical observations to confirm our theories. But seriously, how could you possibly go from small to supermassive without an intermediary step.

    To be horribly crude and insensitive in making an analogy here, you don’t look at obese children and obese adults and then think to yourself “Well, I’ve never seen an obese teenager so maybe they don’t exist.”

  • John

    Nick, that’s what seperates science from all other thinking- speculations, theory, and plain ol’ reasoning are not good enough.
    “Researchers have speculated that super-massive black holes result from the successive fusion of many smaller black holes. But without finding evidence of a medium-size hole, it was a tough theory to prove ”

    Prior to this finding, there was only speculation that large black holes came out of the amalgamation of smaller black holes. For all we know, in fact even after this finding, the enormous black holes we find at the center of galaxies might actually be formed by an entirely different process. When you think about it, there was a very large gap in the sizes of black holes seeen prior to this finding (20x…gap…1,000,000x). And even your crude analogy is flawed because obese teenagers might be obese or not obese because of the changes that occur during puberty, something very different than childhood or adult obesity.

    I would just like to thank you though for providing evidence that all people should take a philosophy of science course, just so that they understand what science is and how it should be done.

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