In the jungle of the senses: today in Extinction Oscillator news...

The Death of Nemesis: The Sun's Distant, Dark Companion

The periodicity is a matter of some controversy among paleobiologists but there is a growing consensus that something of enormous destructive power happens every 26 or 27 million years. The question is what? [An] idea first put forward in the 1980s is that the Sun has a distant dark companion called Nemesis that sweeps through the Oort cloud every 27 million years or so, sending a deadly shower of comets our way. It's this icy shower of death that causes the extinctions.

Today, Adrian Melott at the University of Kansas and Richard Bambach at the Smithsonian Institute in Washington DC re-examine the paleo-record to see if they can get a more accurate estimate of the orbit of Nemesis. Their work throws up a surprise. They have brought together a massive set of extinction data from the last 500 million years, a period that is twice as long as anybody else has studied. And their analysis shows an excess of extinctions every 27 million years, with a confidence level of 99%.

That's a clear, sharp signal over a huge length of time. At first glance, you'd think it clearly backs the idea that a distant dark object orbits the Sun every 27 million years.

But ironically, the accuracy and regularity of these events is actually evidence against Nemesis' existence, say Melott and Bambuch.

That's because Nemesis' orbit would certainly have been influenced by the many close encounters we know the Sun has had with other stars in the last 500 million years. These encounters would have caused Nemesis' orbit to vary in one of two ways. First, the orbit could have changed suddenly so that instead of showing as a single the peak, the periodicity would have two or more peaks. Or second, it could have changed gradually by up 20 per cent, in which case the peak would be smeared out in time.

But the data indicates that the extinctions occur every 27 million years, as regular as clockwork. "Fossil data, which motivated the idea of Nemesis, now militate against it," say Melott and Bambuch.

That means something else must be responsible. It's not easy to imagine a process in our chaotic interstellar environment that could have such a regular heart beat; perhaps the answer is closer to home.


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16 Responses:

  1. Has anyone bother to go to R'lyeh to check Cthulhu's alarm clock yet?

  2. rodgerd says:

    ...but I can't help but find it profoundly depressing to think there's only another 16 million years no matter how well we do.

  3. lovingboth says:

    For once, people should read the comments.

  4. ronaldscott says:

    I find it romantic to think that 27 million years is how long it takes some feckless vertebrate to develop sentience, grow to planetary primacy, and then bend the entire planetary biosphere over and fuck it in the ass through a combination of poor resource allocation and technological holocaust. Nicely ties up the Fermi Paradox.

    My gut tells me that it's all bullshit though and that in fact there is no 27my frequency signal.

  5. leolo says:

    From your previouslied previously, I seem to recall that 27my corresponded (roughly) ot the solar system "bouncing" above and below the galactic disk.

  6. mcity says:

    Quick, someone call Commander Shepard!