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Sun's Dark Companion 'Nemesis' Not So Likely
TravisTR passes along a story about the death of Nemesis. "The data that once suggested the Sun is orbited by a distant dark companion now raises even more questions... The periodicity [of mass extinctions] 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? ... another 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. ... [Researchers] 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."
How long has it been since the last apocalypse? Basically is the odometer rolling around its 27 millionth year? If so can we see something coming? Dust cloud?
isn't this the most simple explaination? Most stars in Mily Way arms are known to bounce up and down the ecliptic.
The second comment under the article seems to be a pretty serious debunking. I'm not going to take sides or tell you who's right and wrong because I don't know, but I will note that arXiv (the source for the claims) is for pre-prints and is not peer-reviewed.
Crap, we're screwed. We are not good at planning ahead. If only we'd had more time.
"Who is the Journal of Quantum Physics going to believe?" --Stephen Hawking
At first I read "1.1 million years" and was really worried
Pathetic earthlings. Hurling your bodies out into the void, without the slightest inkling of who or what is out here. If you had known anything about the true nature of the universe, anything at all, you would've hidden from it in terror. -- Ming the Merciless
Sun's Dark Companion 'Nemesis' Not So Likely
"Nemesis" is the codename for the next MySQL release, to which Oracle is giving the ax. After the 5.1 debacle, I'm not surprised the database is being touted as a "Sun's Dark Companion."
Odd, I just got this weird feeling that I'm being offtopic.
...only it was a larger multiple: somewhere in the vicinity of every 150-180 million years. However, in this case, it's due to our solar system's z-axis oscillation with respect to the rest of the Milky Way galaxy. The dust and gas of the galaxy acts as a shield against cosmic radiation, but every 150-180 million years, our solar system reaches the z-edge of the galaxy and is maximally exposed to the elements.
What accounts for the 5-7 other mass extinctions within that time frame, however, I defer to TFA.
"I'd just like to emphasise that taking a million years isn't a metaphor here..." -Rich Bradshaw
It's been 26,999,998 years since the last mass extinction.
Do you have ESP?
Read the comment "Bad research, worse article" in the comments section. "Melott has made an arxiv carrier of various kinds of pattern searches and catastrophism scenarios in data. (What I would like to call "pseudoscience conspirationism".) " To sum it up, this article is probably sensationalist psuedoscience and there is nothing to see here.
Currently hooked on AMP
Oracle, who are probably going to cause an extinction much earlier than this....
Some more debunking in the second comment:
First off, there is likely no "growing consensus that something of enormous destructive power happens every 26 or 27 million years". It is an old idea, probably originated with the terrible paper by Raup and Sepkoski 1986, which I have criticized on the web several times; (...) [Not to poison the well, but Bambach published lately in Ruse and Sepkoski eds "Paleontology at the High Table." One must take a dim view with the abilities of anyone that choose to cooperate with "philosopher of biology" and known stealth creationist Ruse.]
... Sun's dark companion was called Oracle. When did they change their name to Nemesis?
Have gnu, will travel.
One of the alternate explanations, which is associated with long-term regularity, involves the orbit of the Sun in the Galaxy. Every so often it passes through a dense "arm", and then the Oort Cloud accompanying the Sun gets mixed up with the equivalent clouds surrounding other stars....
Check out the Wikipedia article on the Oort Cloud. The Oort Cloud is thought to be well over a light year across. Out on its fringes the influence of the sun's gravity isn't much stronger than the pull of nearby stars, or the galactic core itself. So whenever the oscillation reverses direction and the sun begins moving back toward the galactic plane, a lot of stuff out on the fringes doesn't move neatly with it. Some of it will become gravitationally unbound from the solar system, but some of it will find its orbit perturbed and start heading inward. Whether that's enough stuff to lead to mass extinctions here on Earth is another matter.
This article mentions disk tides, encountered most strongly as the Sol system passes thru the galactic plane, as the possible culprit in disturbing the Oort Cloud on a regular basis:
http://www.americanscientist.org/issues/pub/perturbing-the-oort-cloud
Well, average life-expectancy of a species is 5-million years. Homo Sapience has already doubled that putting us at the extreme end of the scale that gives this average.
In short, the chances of us being around long enough to need to do something is statistically negligible. Life will be around. Probably even intelligent life. Perhaps this time even life intelligent enough to do something, probably not.
If we were wiped out tomorrow, it's quite likely that zero evidence of our existence would even be around to be found 10 million years from now. There were entire species that we know existed because we have fossils, that were around longer than us - and where we know this because we have two bones. Not two skeletons - two bones.
The assumption that we're the first technologically intelligent species on this planet is just as unscientific as to assume we aren't. The absence of evidence in this case can be just as easily explained by deep time as that there wasn't anything to leave it. But we do have absolute proof that technological societies CAN evolve on earth - because we're here. Thus Occam's razor suggests it's more likely that it has happened before - probably several times than that it hasn't. ...sheez, and I just wanted to expand on your joke by mentioning how low the odds are of our species (or even of the entire class mamalia) still being around in 16 million years...
Unicode killed the ASCII-art *
We have no proof that we're the first, and frankly if we were extinguished tomorrow the statistical odds are that in 5 million years time there will be no single trace of evidence left that we were ever here. To assume that no species in the billion years or so prior to our arrival reached this level is... well it's absurd.
For a geologist it would be pretty trivial to figure out. Merely analyze the distribution and size of mineral deposits of various ages. Why thats odd, all of the coal that was near the surface 5 million years ago is missing, although the stuff thats buried "too deep" 5 million years ago is still here. Same game for oil/gas, oddly enough all the large deposits that were onshore or close to shore 5M years ago are gone, how odd. Another fun one would be our trash heaps. WTF is all this indium ore near all this relatively pure glass ore? How come we find silicon deposits from 5 million years ago that are occasionally ridiculously pure except for commercially useful P-type and N-type semiconductor impurities? Finally, assuming the highly evolved cockroaches that have taken over have advanced beyond us, they'd also notice that certain technologies that they use have not been exploited, 5M years ago they were obviously pretty good at burning this "oil" stuff but they clearly never figured out how to refine boron into anti-matter reactor shielding, or mined graphite to make monocrystaline carbon fiber space elevators, much like a hundred years ago hyperpurified silicon and large lumps of pure uranium metal were not industrially produced.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
So you assume a previous intelligent society would have used the same fuels as us (really ? Fossil fuels used by the "people" whose time fossil fuels were LAID DOWN IN... think about that for a second).
More than that, the very surface of the earth has been reshaped a few times. There was mass vulcanism in Siberia that covered whatever was there originally under about 2 miles of magma round about the same time as the KT event - in fact some scientists believe that the KT event could have CAUSED this... so if our hypothetical intelligent dinosaurs had been living there ... no trace we could find may have survived.
More-over all the stuff you mention are what, 100 years old ? So if we'd died out just a century sooner than right now - no evidence would have survived. We were a pretty advanced technological society even then though.
If what you say is so obvious - and so easy for a geologist to prove - then how come none has ? And no - they haven't. The vast majority of paleontologists and geologists believe it entirely likely that previous societies as technologically advanced as ours could have existed.
Carl Sagan said "Absence of evidence is not evidence of absence". That is true - though of course the corollary is too - it's not proof either.
Here's a little suggestion for you. Whenever you hear "there's no evidence for" as an argument against something being possible - ask three questions:
1) Has anybody looked ?
2) If they did - would they have expected to find anything ?
3) Is the odds of evidence simply being missing bigger or smaller than the odds of it never having existed ?
Here we have:
1) No
2) Maybe - depends who looked.
3) Definitely. So even if somebody looks expecting to find, they may find nothing despite it having once existed.
Unicode killed the ASCII-art *
True but voyager is only 30 years old. More-over - it takes a society who has reached space-travel MORE advanced than ours to find it. If the moon can avoid a meteorite in the are where we left stuff - that has much better odds -but again, would only be discovered by a society the develops far enough to GET to the moon.
Right now - we could have missed it by just 40 years. 40 years out of 3 billion (the age of the earth) is a pretty damn small window and we don't have ANY evidence to believe we will still be here next year - though right now the most likely cause if we're not would be ourselves. Considering we had the most viable means of destroying ourselves BEFORE we went to the moon nearly 50% longer actually)... well you see what I'm getting at?
The corollary is, a society more advanced than ours from the past may have left us a nice little "we were here note" somewhere else - perhaps we'll find it on the surface of Mars or one of Jupiter's moons waiting for our great great grandchildren. Mars would have looked like an ideal candidate even a few decades ago when we thought it had little weather and no major geological activivity - now some scientists believe it has periods of mass vulcanism on a fairly regular basis that basically resurfaces the planet (like what happens on Venus but not so regularly) - so that would make it a less suitable choice.
Even then, unless we go look, we won't know -and even if we look and find nothing it doesn't mean there was nobody to leave a note - it could just mean they weren't bothered to.
Unicode killed the ASCII-art *
At my house, Nemesis shows up about every 28 days.
Well, average life-expectancy of a species is 5-million years. Homo Sapience has already doubled that putting us at the extreme end of the scale that gives this average.
How are you doing your math? The genetic evidence shows that Homo Sapiens can be traced back 200,000 years. Nowhere near the 5 million you are stating as an average for species longevity. If you are counting Australopithecus anamensis, that would get you back to 4 million years, but I would hardly consider it to be the same species as us.
Furthermore, the actual average longevity of a species is 1 million years, not 5 (as evidenced here. Just because 10 million years appears to be an extreme upper limit does not make the average 5 million.
Evidently the motion of the sun through the arms doesn't have the correct periodicity.