Mass Holes

Where Do They Come From?

A simulated view of a 10-solar-mass black hole 600 miles (900 km) away from the observer -- and against the plane of the Milky Way Galaxy.  (Courtesy Wikimedia)
A simulated view of a 10-solar-mass black hole 600 miles (900 km) away from the observer -- and against the plane of the Milky Way Galaxy. (Courtesy Ute Kraus, Physics education group Kraus, Universität Hildesheim, Space Time Travel, (background image of the milky way: Axel Mellinger) via Wikimedia at; click to biggify.)

No, today’s entry is not about automobile drivers in Massachusetts. It’s about black holes — those ubiquitous conglomerations of huge amounts of mass — that have such strong gravitational influences that nothing (not even light) can escape their grasp. These are truly mass holes — or think of them as “mass sinks”, where mass (stars, gas, dust, etc.) is deposited and can never be retrieved.

Black holes have been around as theoretical constructs (i.e. an idea in somebody’s head) since at least the 18th century. As actual objects, however, they’ve been around probably since the beginning of the universe and they come in various flavors (or types, and if you want a more rigorous discussion of the physics behind a black hole, go here or here).

So, where do these mass holes come from?  How do they form?

The ones we’re most familiar with are those that form when a supermassive star collapses in on itself (in a supernova explosion) or when a pair of massive stars (a massive binary) somehow manage to merge together.  In either case, the matter in the stars is so dense and there’s so much of it that not even the individual atoms and neutrons in the star’s core can withstand the pressure to keep collapsing.  When it does, a new black hole is born — and becomes what astronomers call a “stellar mass” black hole.

The motions of stars around the black hole at the center of the Milky Way Galaxy. This is a time-lapse movie in infrared light, courtesy Astronomy Picture of the Day.

The other astronomically interesting types of black holes are the supermassive ones that lie at the hearts of galaxies and gobble up stars and clouds of gas and dust. In very active galaxies — that is, the ones with jets shooting out from their hearts — the black holes are incredibly massive, often containing the equivalent of the mass of millions or billions of stars.

Our own galaxy has at least one black hole at its heart, and although it doesn’t shoot out a jet, it does eat up material and it does influence the motions of stars in its nearby neighborhood.

The big mass holes at the hearts of galaxies probably formed when the galaxies they live in were built through the collisions of two or more older galaxies that already had central black holes. As time went by, those black holes just continued to eat up more and more stars, growing ever larger.

There is a class of black holes that probably exist called intermediate-mass. They most likely form when smaller black holes (those that are several times the mass of a stellar black hole) collide with each other.  And, at the other end of the black hole spectrum, we have the micro black holes (sometimes called “mini black holes” if you want to be cute about it).

We haven’t seen any of these forming,yet. But they could have blipping in and out of existence during the very earliest epochs of the formation of the universe, and if they have formed, the gamma-ray radiation from their evaporation could be detectable. It’s also possible that (if it gets working again) the Large Hadron Collider could create some short-lived mini black holes during its experiments. There’s nothing to worry about, though. They wouldn’t last long enough to do damage.

No matter how they form, black holes are among the most interesting creatures in the cosmic zoo of objects that astronomers study.  And, as long as galaxies keep making massive stars and/or colliding with each other, astronomers will have plenty of them to study “in the wild.”


  1. Bjoern

    There is no motion in this gif, the galaxy is not pulled around in any way. What you are seeing there is merely an optical effect called a “gravity lens”: the gravity of the black hole makes the light going around it curve (like an ordinary lens bends light), and therefore you see a distorted picture of what lies behind it.

  2. ccp

    This is an animated gif — I see motion so perhaps your browser isn’t allowing motion. Check your settings. As for the lensing effect — go read the page accompanying the gif — it explains what you’re seeing — but the motions of the stars around the black hole at our galaxy’s heart are real and have been documented.

  3. Bjoern

    Sorry, probably a misunderstanding: I assumed that “SupplementAndNutrition” talked about the first picture (“A simulated view of …”), not the second one (“The motions of stars …”), since he talked about “this galaxies” (sic). In the second picture, obviously there should be motion (although indeed my browser isn’t showing that), but that second picture shows stars, not galaxies.

  4. ccp

    That’s right — it does show stars — they are the stars orbiting the black hole at the center of our own galaxy. I suspect the OP probably meant stars, not galaxies… perhaps a typo on his/her part.

  5. yang

    Earth will turn into black hole. Alas, once it is prosperous planet that is the most beautiful and plentiful like oasis of the desert, will fall into eternal darkness.

  6. ccp

    Ah, you haven’t done the calculations for what it would take to turn Earth into a black hole, have you? Another beautiful fantasy sunk by reality. 😉

  7. Aquarian

    The universe is amazing; a treasure chest full with vast wonders more precious than any diamond. Only the humand mind can compare to the universe and its borders without end. Secrets of Secrets hidden deep within the massive vault of primal darkness.

  8. Anonymous

    2012 is another doomsday theory that will come to be proven wrong. it is exactly the same as the y2k, people overreacting and refusing to use judgment or logic whatsoever.

  9. ccp

    Black holes are essentially very dense collections of matter with gravity so strong that not even light can escape. They can form when massive stars explode and the leftovers collapse to a dense core; they can form when two or more black holes collide and merge.

  10. deny

    I’m not a smart one or some weird people with huge glasses i just an ordinary man with some interest in science…
    well anyway i think the black hole theory is only a fantasy theory. Some stars have gravity and to prevent its surface collapses to its center the stars use energy from nuclear chains reaction with Hydrogen use as its fuel. Mathematically some stars has run out its fuel so its surface collapses down. Since it has a huge mass, it has huge gravity and the story tells “even the light from its dead stars wont come out”. I think its just daydream it just like Darwin’s evolve theory that never proven. The difference is to proof the black holes theory we had to go out for some light year distance. But Im sorry to tell you that around our earth there exist some calls van allen’s belt. For me the proof as the X-ray photo isnt enough to the existence of dead stars become vampire that eat others stars. I believe that some powers is beyond the lens effect we see from earth. That power is God. believe me that our universe is had an amazing creators. Think this : where come from weird energy such as gravity, and why in the atom’s nucleus it has many protons although we knows that protons is always hate with each others.
    may be so may be dont…

  11. ccp

    Let your interest in science educate you further; by this, I mean do the actual work to understand the laws of physics that describe what happens in the cosmos. You may come back here after you have learned more and realize how uneducated your answer is. Throwing a magical sky fairy in there for discussion was a nice touch though, but you can’t prove that exists, can you?

    My advice: learn more about these things before you attempt to sound like an expert.

  12. jeg

    This website is very informative. I’ve heard if a black hole the size of a quarter landed in the center of the earth it would completely swallow it. Is that true?

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