back to article Supermassive black holes scoff just one star per year, say space weight watchers

Supermassive black holes in merger galaxies snack on one star every year, according to a paper published on Thursday. The Andromeda galaxy, also known as Messier 31 or M31, sits next door to the Milky Way only about 2.5 million light years away. It’s a giant spiral galaxy teeming with stars and astroboffins have spotted a pair …

  1. Destroy All Monsters Silver badge
    Paris Hilton

    That's weird

    It is not likely that a dwarf galaxy brings a supermassive black hole to the table. But the Andromeda doesn't look like the result of a larg-ish merger. It is not elliptical, has not whispy hang-ons or stuff in ex-centric orbits.

    1. eldakka Silver badge
      Boffin

      Re: That's weird

      > It is not likely that a dwarf galaxy brings a supermassive black hole to the table.

      They are beginning to think that it's normal for even Dwarf Galaxies to have SMBH's.

      Supermassive Black Hole Discovered Inside Tiny Dwarf Galaxy:

      The supermassive black hole is about five times more massive than the one at the center of the Milky Way, but the dwarf galaxy in which it was found--known to astronomers as M60-UCD1--is about 500 times smaller than our own galaxy,...

      The discovery suggests that supermassive black holes may be twice as numerous in the nearby universe as previously thought, ...

      The discovery suggests that there are many other small galaxies containing supermassive black holes....

  2. DougS Silver badge

    One solar mass a year

    Means they should be billions of solar masses by now. So how come most of them weigh in at a svelte few hundred million solar masses?

    1. John Mangan

      Re: One solar mass a year

      From the article it looks like the one star/per year is a relatively short-lived period of activity.

    2. Alan Brown Silver badge

      Re: One solar mass a year

      Supermassive black holes may scoff one star a year but only 1-3% actually crosses the event horizon.

      The rest is sprayed around even more messily than Cookie Monster let loose in an Arnott's warehouse.

      Om nom nom nom nom!

  3. unwarranted triumphalism

    I'm glad to see they haven't been wasting their time with frivolities.

  4. Cubical Drone

    3.669 per cent of the maximum velocity of a sheep in a vacuum in Reg units

    Kudos for putting the speed in a form that us Reg readers can get our heads around.

    1. Lamb0
      Boffin

      Re: 3.669 per cent of the maximum velocity of a sheep in a vacuum in Reg units

      However, you still need to put the decimal in the correct place... two to the left!

      => i.e. .03669% of the maximum velocity of a sheep in a vacuum in Reg units.

  5. David Roberts Silver badge
    Alien

    Visualisation of the cosmic all

    If these black holes are eating one sun a year, what are the odds that at least one sun had habitable planets with perhaps sentient life?

    1. KegRaider

      Re: Visualisation of the cosmic all

      I would say if there was any 'intelligent' life, they would have long gone before getting into that lunch zone. However, if they were primative thugs like ourselves, I hope it was quick and painless for them.

    2. mr.K

      Re: Visualisation of the cosmic all

      Feel free to correct me if I am wrong about this. I think that the conditions, basically the climate, on a planet is not solely dependent on the sun it orbits, but also on radiation from nearby and faraway sources in space. I thus imagine that being thrown through centre of a galaxy on a regular basis will tend to make the planet inhabitable. Not to mention what the gravitational forces nearby stars can do the orbit. So any life on these rocks will be long gone before they get eaten by a black hole. So unless they are truly advanced and can vacate the premises, and move to a mostly harmless planet orbiting a star situated far out in the uncharted backwaters of the unfashionable end of the Western Spiral Arm of the Galaxy, they are goners.

      As for the odds, I'll recommend starting with Drake's equation and narrow it down to the set of stars involved.

      1. Alan Brown Silver badge

        Re: Visualisation of the cosmic all

        " but also on radiation from nearby and faraway sources in space."

        Correct to a point, that's why a nearby supernova would make for a bad day on earth.

        Even without that risk, our own star will make the surface uninhabitable in less than 500 million years (it's getting hotter as it gets older), and this tendency of stars makes the window for evolution of intelligent life that can get itself space-faring before extinction in any given system even smaller than we might think.

POST COMMENT House rules

Not a member of The Register? Create a new account here.

  • Enter your comment

  • Add an icon

Anonymous cowards cannot choose their icon

Biting the hand that feeds IT © 1998–2019