Follow Slashdot blog updates by subscribing to our blog RSS feed


Forgot your password?

Dinosaurs Done In By... Dark Matter? 135

bmahersciwriter writes "Theoretical physicists propose that the Sun periodically crosses into a dense layer of dark matter sandwiching the Milky Way. The gravitational push and pull that this creates disturbs debris in the Oort cloud sending deadly comets and asteroids ricocheting around the solar system. This passage happens, their admittedly speculative model suggests, every 35 million years, which jibes somewhat with evidence on impact craters. Take it with a dino-sized grain of salt."
This discussion has been archived. No new comments can be posted.

Dinosaurs Done In By... Dark Matter?

Comments Filter:
  • by fullmetal55 ( 698310 ) on Friday March 07, 2014 @06:47PM (#46431619)

    seriously how long until someone claims that this happens every 35 million years and the clock is ticking down to Nov 10, 2016.

  • by Daniel Dvorkin ( 106857 ) on Friday March 07, 2014 @06:48PM (#46431625) Homepage Journal

    I understand why they're getting a weak signal here on Earth, where most craters will have long since been erased by erosion and surface remodeling. But I'll bet we could get a much stronger signal from the Moon, particularly the far side. Do we have the ability to get dates for craters there from orbiting probes, or is that something we'd have to collect physical samples to do?

    • IIRC you can estimate crater age by counting the # of smaller craters/area and using statistics.

      • Okay, makes sense. So we probably already have the data available to do a pretty good analysis of impact periodicity.

        • by HornWumpus ( 783565 ) on Friday March 07, 2014 @07:06PM (#46431719)

          Of course, if their hypothesis is correct all the statistical data will have to be re-calibrated to account for the occasional rain of meteors.

          Also note: Age estimates for larger impacts will have smaller error bars.

          • Urgh. Good point.

            I'll bet there's a model that could take all stuff this into account, and sufficient data to estimate the parameters. But trying to figure out what that would be feels too much like work.

        • by narcc ( 412956 )

          I remember Richard Muller (Berkeley physicist) writing something about that in Nemesis: The Death Star (It's a pop-sci book, not science fiction as the title implies.)

          • I was just about to say, "the return of the Nemesis theory", except that "theory" was always too strong a word for that - "conjecture", perhaps.

            The idea was that sub-stellar-mass dark companion of the Sun would pass near enough to the Oort cloud to throw a barrage of comets into the inner solar system every 35 million years or so, and that we're just about due. The name of this object would be "Nemesis". (I think Asimov wove that into the end of one of his last stories,,,)

            I still like this as a working

      • flawed (Score:3, Insightful)

        Except that to do this you first assume uniform distribution of impacts wrt time...
  • There seems to be some rather big assumptions being made here, like the nature of dark matter.
    • Re: (Score:2, Funny)

      by The123king ( 2395060 )
      Or that dark matter actually exists. I've never seen any definitive scientific evidence of the existence of it. Dark matter just seems to be that stuff we use to answer anything we don't quite understand. Big Bang? Dark matter. Quantum physics? Dark matter. Extinction of the dinosaurs? Dark matter. Why is yo mamma so fat? Dark matter.
      • by suutar ( 1860506 ) on Friday March 07, 2014 @07:16PM (#46431777)
        Just remember, dark matter is for explaining why very big things don't fly apart, and dark energy is for explaining why even bigger things do.
        • That is the best description of dark matter and energy that I have ever seen. I'm going to save it alongside the best description of wealth creation I have.
      • Some string theorists claim that when a string bends in the 4th dimension it creates the effects of dark matter.

        Not to sound like an idiot because I have no physics degree, but if it exists everywhere why isn't it on Earth or anywhere else? Surely in the last billion years since our solar system revolved around the galaxy once we would at least encounter some of it?

      • by Anonymous Coward

        Every reality-motivated explanation begins as a convenient way to to explain something not presently understood. Photoelectric effect not making sense with classical E&M? Hmmm, what if light came in discrete packets.

        Dark matter was at the stage you seem to think it's at around 1960: "Hmmm, it would be convenient if there were more mass where we can't see it..." Starting from the Bullet Cluster, we have observed nearly a dozen galactic cluster collisions where the stars and dark matter pass right by/thro

  • by ArcadeNut ( 85398 ) on Friday March 07, 2014 @06:54PM (#46431665) Homepage

    Real Reason []

  • by Anonymous Coward

    I caused the extinction of the Dinosaurs

    Fred F.

  • In retrospect, I rather regret not leaping on some bizzare and obscure science topic very early on in my career. With my early knowledge of pop-science and fantasy TV, film, and comic books, I could have made big headways in modern cosmology and theoretical physics by now.

    • by lgw ( 121541 )

      Sure, all you have to do is make numerically accurate predictions of future observations, how hard can that be? Or failing that, just be a String Theorist ...

    • It's never too late to start. Unless you've already started, then it's too late.
  • by Connie_Lingus ( 317691 ) on Friday March 07, 2014 @07:18PM (#46431797) Homepage

    obviously, the dark matter came from Uranus

  • by wjcofkc ( 964165 ) on Friday March 07, 2014 @07:25PM (#46431857)
    If you look over the past 500 billion years, the geological record shows that there is a mass extinction event roughly every 62 million years. Even though there is some give and take, on that timescale it's almost like clockwork. Since this discovery, scientists of many disciplines have been trying to figure out what could be causing it. While I admit that it could be a cosmic coincidence, if not, then somewhere a culprit is lurking. There are also lesser extinction events every 26 - 35 million years.

    For more on the 62 million year problem []

    More on mass extinction events in general []
    • If you look over the past 500 billion years, the geological record shows that there is a mass extinction event roughly every 62 million years.

      So we have records of about, what, eight thousand mass extinctions? Wow, I had no idea. ;)

      • by wjcofkc ( 964165 )
        Or roughly 130 over the last half-trillion years. Consider yourself educated. At least that's what's happens when physics meet geology.
        • I think you need to recheck your math.

          500 billion divided by 62 million equals 8,064.5, so I don't understand where the 130 number is coming from.

          Even if you were thinking 'million' as you typed billion, 130 still makes no sense, as 500 million divided by 62 million equals 8.

          Best current estimates on the age of the universe are much smaller than 500 billion, more like 14-15 billion.

          Where does the 500 billion come from?

          BTW, other than the maths, you made an interesting comment. :-)

      • Yeah, I feel 'sucker-punched' by this as well.

        All of those lying, conniving scoundrals that call themselves scientists have been trying to convince me for years that the universe was only 14 1/2 billion years old.

        Man, I feel old now....

        Hey wait, maybe this explains the universe's trying to catch up with the new info. Yeah, that's gotta be it. ;-)

    • > If you look over the past 500 billion years, the geological record shows that there is a mass extinction event roughly every 62 million years.

      Oddly enough, that works out to 1/4 of a galactic year to three decimal places.

      Galactic seasons?

    • If you look over the past 500 billion years, the geological record shows that there is a mass extinction event roughly every 62 million years. Even though there is some give and take, on that timescale it's almost like clockwork. Since this discovery, scientists of many disciplines have been trying to figure out what could be causing it.

      Computer scientists think about it for about two seconds. Then they mutter "Must be the garbage collector" and go fetch a beer.

  • Are these things being obsoleted? The most discussed and hot comments boxes haven't been updated in a week or two. Is the beta rollout still happening?

    • by rts008 ( 812749 )

      Is the beta rollout still happening?

      If I remember correctly, the beta was not going 'live' until the end of March, or beginning of April.

      I for one, was hoping it was an elaborate April Fools joke on /.'s part.

      You have to admit, this one would go down in history as bigger than the year we were subjected to 'OMG...PONIES!!!'

      I don't really expect /. beta to be an April Fool, unfortuneately.

  • Yesterday, a story about upskirt photos being legal in Massachusetts and today dark matter killing off the dinosaurs.

    Coincidence? I think not.

    You know, it's amazing the insights that a few Friday afternoon cocktails can bring.

    Add in Li'l Boosie getting released from prison today, and you can't tell me the Illuminati isn't behind all this. Maybe.

  • Sharks with lasers on their heads is so 20th century.
  • LOL From TFA.... "Dissipative dark matter is a possible explanation, but it’s not clear that it’s explaining anything real"
  • Dark matter? (Score:2, Insightful)

    by Karmashock ( 2415832 )

    I'm not a physicist but every description I've heard of dark matter more or less boils down to "we've noticed there is more gravity in areas where we don't see mass. And since only mass can generate gravity we have missing mass. We're going to call that missing mass dark matter."

    Okay... fine... but that's entirely theoretical. No one has actually found dark matter... as in put it under a microscope or touched it. So... until then, lets not come up with any halfassed theories regarding it.

    • by lgw ( 121541 )

      Okay... fine... but that's entirely theoretical.

      Right, like all of science.

      No one has actually found dark matter... as in put it under a microscope or touched it

      Right, like all of cosmology.

      There's solid evidence for the existence of dark matter - it's composition remains a mystery as early hypotheses aren't panning out.

      What I don't get is why anyone would think Dark Matter would form layers above and below the galactic disk. Hard to see why the distribution about the galaxy would be anything but spherical.

      • It would seem to follow that dark matter would tend to naturally form some type of structure. Normal matter certainly forms rather consistent shapes on many different scales. What shapes would dark matter favor if it only interacts gravitationally? Wouldn't it form either a dense ball at the bottom of our galactic gravity well, or flatten into a disc with the rest of the matter in our galaxy? I don't think I've ever read any real theories on it.

        • by ceoyoyo ( 59147 )

          Both matter concentrating in the middle and forming disks is due to it interacting with itself. Friction, basically. Dark matter doesn't do that.

  • Everybody knows that it was Nibiru.
  • I believe this is real. It's on one of those other god like astro physics levels of things, that people don't understand. Like mind control, and directed-energy weapons. People don't understand shit about the universe, how cold it is, or how fucking dangerous and volatile it is ..

    I think we should ditch planet earth now and focus on building an artificial planetary system which can avoid other planets, comets, energy, and other uncontrollable systems. Immediately, as soon as we can, before we ourselves pari

  • by petsounds ( 593538 ) on Friday March 07, 2014 @09:16PM (#46432479)

    "So what if there was this giant swarm of space bees, and every 35 million years our solar system–"
    "Wait. Wait, hold on. You're suggesting space bees killed the dinosaurs?"
    "Not directly! These bees are huge. Moon-sized. And they live in the interstellar gaps between stars. I calculated that if their swarm passes through the Oort Cloud, they would get really upset and buzz around, and their gravitational forces would fling asteroids and comets into the solar system."
    "How did you calculate that the Oort Cloud makes your hypothetical space bees angry?"
    "Well it's a lot more plausible than your hypothetical invisible aether making the sun go wonky."

  • There's a flaw I see here. When the solar system was formed, chunks of stuff flew around in random directions and collided and there's X chance that one hits Earth. So something comes along and alters the trajectory/orbits of some of this stuff, also randomly. The probability that one hits Earth does not go up. You took something random and made it differently random. For this to be true, the vast majority of matter would regularly have to have magically been specifically not on a trajectory to eventua
  • Which Dinosaur? There were lots of sizes! I need to quantify this immediately or my brain will turn into dark matter! Get it? Grey matter, dark matter...Laugh or I'll turn this solar system around and we'll go right back to the dark matter.
  • Apart from the mention of Dark Matter, which seems to be a perennial favourite these days, this theory is not new. It was first proposed c.1986 at least.
  • Dark matter is like the UFOs of astronomy. It's only called "dark" because they don't know what it is yet! UFOs are only "unidentified" until they identify the flying object. There's no reason to think that "dark matter" is something mysterious or alien, astronomers just can't see it...because it doesn't glow!

  • I read about this exact subject some years back, kinda late news, chum?
  • Article extract:

    The signal is very well fit by a 31-40 GeV dark matter particle annihilating to bb_ *** with a density of 0.3 GeV/cm^3.

    *** bb_ (note: that's a bottom quark and a bottom antiquark)

    WIkipedia "Bottom quark":

    There are many bottomonium states .... These consist of a bottom quark and its antiparticle.

    Conclusion: Dark matter decays to a state of bottomonium.

Have you ever noticed that the people who are always trying to tell you `there's a time for work and a time for play' never find the time for play?