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New Theory Explains Periodic Mass Extinctions

Posted by Zonk on from the we're-not-due-for-a-little-while-yet dept.

i_like_spam writes "The theory that the dinosaurs were wiped out by an asteroid impact, the K-T extinction, is well known and supported by fossil and geological evidence. Asteroid impact theory does not apply to the other fluctuations in biodiversity, however, which follow an approximate 62 million-year cycle. As reported in Science, a new theory seems to explain periodic mass extinctions. The new theory found that oscillations in the Sun relative to the plane of the Milky Way correlate with changes in biodiversity on Earth. The researchers suggest that an increase in the exposure of Earth to extragalactic cosmic rays causes mass extinctions. The original paper describing the findings is available online."

30 of 383 comments (clear)

  1. Huh. Better get to work! by SatanicPuppy · · Score: 5, Interesting

    Only 7 million years from now, for all you long range planners. Better stock up on beans, bottled water and relocate your house 1 kilometer underground.

    It's a perfectly reasonable hypothesis, though it'll be a while before we can test it. It's always a little weird though, to think of extra-solar events as relevant on a "local" scale. I mean, in the same way that Earth is endangered by rogue meteorites and asteroids, the whole solar system is vulnerable to a rogue star or brown dwarf. Anyone ever read Jack McDevitt? He's obsessed with that sort of disaster (pun intended).

    Hard to get your mind around it...The odds are so long...

    --
    ad logicam Claiming a proposition is false because it was presented as the conclusion of a fallacious argument.
    1. Re:Huh. Better get to work! by Shadow+Wrought · · Score: 5, Funny
      So we have 7 million years to figure out space flight and/or a way to record the sum of our knowledge for future intelligences.

      We're hosed.

      --
      If brevity is the soul of wit, then how does one explain Twitter?
    2. Re:Huh. Better get to work! by SatanicPuppy · · Score: 4, Insightful

      It's not every species that lasts 7 million years. It's just as likely we won't be here at all, and this event will only bother the emerging rat civilization.

      I'd be surprised if we haven't shot our bolt one way or the other in the next ten thousand years, and that's a conservative estimate.

      --
      ad logicam Claiming a proposition is false because it was presented as the conclusion of a fallacious argument.
    3. Re:Huh. Better get to work! by Anonymous Coward · · Score: 5, Funny

      Dude... A house 1 kilometer underground, and you want to stock up BEANS??

    4. Re:Huh. Better get to work! by Sponge+Bath · · Score: 5, Funny

      ... the emerging rat civilization

      Let me guess: the rats are the warriors, the hamsters are the scientists,
      and a bright orange guinea pig named Dr Zeus will be in charge.

    5. Re:Huh. Better get to work! by slashname3 · · Score: 4, Insightful

      Only if you leave it to the government to figure out space flight.

    6. Re:Huh. Better get to work! by Loke+the+Dog · · Score: 4, Interesting

      Which is kind of cool to think about... Imagine if rats have built a civilization about on par with our current civilization, but they are just a few years from this catastrophic event when they discover this pattern. And they are desperately searching the human ruins in hopes of finding some kind of technology to deal with this. It would make a good movie, I think.

  2. It burns... by unchiujar · · Score: 5, Funny

    Will my tinfoil hat protect me ?

    --
    Shakespeare poems - infinite monkeys with infinite time.Computer tech support - a few trained ones working from 9 to 5.
  3. Err.. by HitekHobo · · Score: 4, Insightful

    How about 'new hypothesis may explain...'

    --
    A couple of 30-somethings embark on the ultimate roadtrip
  4. Re:Does anyone make.... by Creepy+Crawler · · Score: 4, Funny

    Im sure the Chinese do.

    --
  5. Nah this is not correct either. by 140Mandak262Jamuna · · Score: 5, Funny
    What? Sun? Galactic Plane? Intergalactic Rays? You guys are watching way too many reruns of Star Trek.

    Everyone knows the extinctions were perfectly explained using the Theory of Intelligent Smiting.

    --
    sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
    1. Re:Nah this is not correct either. by Himring · · Score: 4, Funny

      lol! I love making fun of god. It's ok too, cuz god's gotta sense of hu

      [NO CARRIER]

      --
      "All great things are simple & expressed in a single word: freedom, justice, honor, duty, mercy, hope." --Churchill
    2. Re:Nah this is not correct either. by AJWM · · Score: 5, Informative

      You forgot to mention Christopher Columbus's theory that the earth is round... [...]when the rest of the so called "Intelligent" people of the world said it was flat.

      LOL! You still believe that nursery school myth?

      NO intelligent person in Columbus's time thought the world was flat -- as it clearly is not to anyone sufficiently observant. Columbus's problem is that he wanted to go to Asia via a western route, and everyone intelligent knew that with a circumference of about 25,000 miles, Eratosthenes having calculated it about 240 BC (as others had since). Hence they "knew" that with the sailing technology of the day, there was no way Columbus could make the voyage.

      They were right, too. Had the Americas not been in his way, his expedition would have perished before he got as far as the longitude of Hawaii.

      There is some evidence that Columbus may in fact have known that there was some land mass to the west considerably before Asia (the Vikings certainly did, and it is quite possible that fishermen who went as far as the Grand Banks were also aware). Whether from that he decided that Eratosthenes was wrong and the circumference was smaller (possibly influenced by Ptolemy's maps (from Geographica) which underestimated the circumference at about 18,000 miles), or whether he was just arguing that way to get backing for an expedition (with the secret purpose of discovering and exploiting just whatever land mass was there), we have no way of knowing.

      That mistake alone discredits the rest of your post as to make it not even worth reading.

      --
      -- Alastair
    3. Re:Nah this is not correct either. by AJWM · · Score: 4, Informative

      BTW, even though Columbus "discovered" the Americas, it was Juan Sebastian Elcano who proved the world was round by sailing westward (modulo a few detours) until he returned to Spain. Yeah, everyone says it was Magellan, but Magellan died on the expedition in the Philippines, it was Elcano who assumed command at that point and finished the circumnavigation (along with a dozen or so shipmates).

      --
      -- Alastair
  6. Figure 4 in the paper by Pausanias · · Score: 5, Interesting

    Check out Figure 4 at the end of the linked paper. It shows that the periods of highest diversity coincide with the periods where the cosmic ray flux is lowest. Really amazing correlation if you ask me.

  7. Re:Well, that would explain by eln · · Score: 5, Informative

    The article suggests that this does not explain the K-T event, which is already adequately explained by the asteroid impact theory. This theory explains the cyclical decreases in biodiversity that seem to happen about once every 62 million years. The K-T event is not part of this cyclical pattern.

  8. Or Maybe... by MxTxL · · Score: 5, Insightful

    The researchers suggest that an increase in the exposure of Earth to extragalactic cosmic rays causes mass extinctions.

    Or maybe, the increased radiation merely causes some periods of increased mutations... extinctions follow as species are outcompeted for resources.

  9. (5am posting, sorry) by ggvaidya · · Score: 5, Funny

    ... extragalactic cosmic rays causes mass extinctions ...

    Can we please oh please oh please call them death rays?
  10. Perfectly reasonable hypothesis? by benhocking · · Score: 4, Interesting

    It's a perfectly reasonable hypothesis if one accepts the premise that mass extinctions have an approximately 62 million year period. From Wikipedia, the last 6 extinction events happened 65 million years ago, 200 million years ago, 251 million years ago, 360 million years ago, 444 million years ago, and 488 million years ago. The time between extinctions being 135 million years, 51 million years, 109 million years, 84 million years, and 44 million years. I'm having a hard time wrapping even an approximate 62 million year period into those.

    --
    Ben Hocking
    Need a professional organizer?
    1. Re:Perfectly reasonable hypothesis? by gEvil+(beta) · · Score: 5, Funny

      Sounds like someone needs to edit Wikipedia to make this hypothesis fit a little better...

      --
      This guy's the limit!
    2. Re:Perfectly reasonable hypothesis? by ajs · · Score: 4, Informative

      It's a perfectly reasonable hypothesis if one accepts the premise that mass extinctions have an approximately 62 million year period. From Wikipedia, the last 6 extinction events happened 65 million years ago, 200 million years ago, 251 million years ago, 360 million years ago, 444 million years ago, and 488 million years ago. You're looking at the largest of the extinction events. This theory is attempting to explain a particular set of events which result in only an approx. 10% drop in biodiversity, and which are about 60ish million years apart.

      The KT event, for example, had a much larger impact on biodiversity but happened off-cycle, and is pretty clearly the result of a specific meteor strike that we already know about.

      Other events may have been volcanic or meteoric or the result of something we didn't know about.

      All extinction events being triggered by only one type of external condition was never very likely.
  11. Well... by Chouonsoku · · Score: 5, Funny

    I for one welcome our new cosmic ray-based overlords! (I just felt like I hadn't seen that lately. :'( Mod me as you wish. But, be gentle.)

  12. to quote inidana jones: by conspirator57 · · Score: 5, Insightful

    you say: "A truth is a fact,"

    Indiana Jones says, "Archaeology is the search for fact... not truth. If it's truth you're looking for, Dr. Tyree's philosophy class is right down the hall."

    --
    "If still these truths be held to be
    Self evident."
    -Edna St. Vincent Millay
  13. Why not? by SatanicPuppy · · Score: 4, Insightful

    Radiation doesn't kill things off that well. Look at Chernobyl or the Savannah river plant...Both shut down, both radioactive, both experiencing a resurgence of pretty healthy wildlife across the board.

    Lot of the things we assumed about radiation back in the day (e.g. mutants and Godzilla) have turned out to not really happen so much. DNA isn't as fragile as we assumed, and while the extra rads may kill you quicker (only live to 60 instead of 80), it's not quick enough to keep you from reproducing.

    We're not talking some kind of galactic nuke here...It's just a significant upswing in radiation. Hell, the fact that we've had these historically is maybe why the ecosystem tolerates increases in radiation so well.

    --
    ad logicam Claiming a proposition is false because it was presented as the conclusion of a fallacious argument.
    1. Re:Why not? by smellsofbikes · · Score: 4, Interesting

      I have some friends with PhD's in nuclear science who claim that radiation is beneficial. They go further: life started when there was a lot more radiation, so most of our genetic machinery is designed to work with far higher radiation than what we're seeing, which is to say we can stand a lot more radiation with little harm. They go further and claim that because there's less radiation now, we have more problems -- higher background radiation might act to suppress immune system malfunctions (sitting in radioactive hot springs does seem to reduce the symptoms of arthritis.) Life survival vs. number of cells should be inversely proportional as radiation level rises: if a bacterium has its DNA badly injured by a radiative event, it's less likely to survive than an animal with a million cells. (I've read in other places that every strand of DNA in every cell experiences tens of damage events requiring repair every day.) My friends the PhD's go so far as to claim that the reason that the seven counties in the US with the longest average lifespan are all on the Continental Divide in Colorado where the radiation levels are highest because of the elevation.
      (Sorry I can't find a better link for the Eight Americas dataset: you have to download an Excel spreadsheet to get the raw data.)

      --
      Nostalgia's not what it used to be.
  14. Some hasty objections by Michael+Woodhams · · Score: 4, Informative

    OK, I've only read the summary (I have a lecture to give half an hour from now to prepare for) but I can see some objections:

    * My boss (David Penny, Massey University) argues that the mammals and birds were already outcompeting the dinosaurs at the end of the cretaceous, so the asteroid was at best a coup-de-grace for them.
    * The "periodic extinctions" idea has been around for decades, including the possible link to oscillations through the galactic plane.
    * Mass extinctions are sudden. The increase in extragalactic cosmic rays exposure would be slow, over millions of years.
    * The extragalactic cosmic ray exposure changes should be highly regular. The extinctions are irregular.

    --
    Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
  15. Re:You'd have to pass through the heliopause first by CommunistHamster · · Score: 4, Informative

    The Pioneer and Voyager probes weren't designed to specifically leave the solar system though, their primary mission was to probe the planets. If we made a probe dedicated to getting really far out of the solar system really fast (with no stops in between Earth and deep space, or indeed at all) then it would get there much faster.

  16. Biodiversity by benhocking · · Score: 4, Informative

    Perhaps increased Cosmic Rays caused a massive amount of mutations that forever changed the genetic data of organisms by making them more likely to survive.
    Along those lines, I found this interesting figure in Wikipedia that also mentions the 62 million year cycle.
    --
    Ben Hocking
    Need a professional organizer?
  17. NOT About Mass Extinctions! by markk · · Score: 5, Informative

    The title of the summary is totally wrong. This has nothing to do with mass extinctions. Its looking at fossil Species and Family counts vs time correlated with Solar motion. The 62 MY cycle barely touches the Mass extinction events.
    Better summary title - "Life's Diversity changes with Solar Galactic Orbit". Or something like that.

  18. Re:Well, that would explain by inviolet · · Score: 4, Informative

    Fewer cosmic rays mean fewer clouds will be formed, and so there will be a warmer Earth. If the sun and the solar wind are not so active, then more cosmic rays can come in. That means more clouds [reflecting away more sunlight] and a cooler Earth.

    That's odd. The post-9/11 research into the effects of jet contrails suggested that they have two faint effects: mild warming and mild day/night temperature moderation. But the above quote seems to contradict that.

    I am now even more suspicious of the conclusions of the contrail research, coming (as it did) in the middle of the global warming craze. Right now you can't even publish the simple observation that plants will grow usefully faster on a warmer Earth; no, you have to spin it as "OMG poison ivy will get worse!".

    I'm ready to go nuclear/solar/wind, and drive an electric car, because I've always hated the power that petronomics gives to the backwards nations... but come on guys, can we at least give both sides a fair hearing?

    --
    FATMOUSE + YOU = FATMOUSE