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Linking Mass Extinctions To the Sun's Journey In the Milky Way
schwit1 writes "In a paper published today on the Los Alamos astro-ph preprint service, astronomers propose that as many as eleven past extinction events can be linked to the Sun's passage through the spiral arms of the Milky Way. (You can download the paper here [pdf].) From the paper: 'A correlation was found between the times at which the Sun crosses the spiral arms and six known mass extinction events. Furthermore, we identify five additional historical mass extinction events that might be explained by the motion of the Sun around our Galaxy. These five additional significant drops in marine genera that we find include significant reductions in diversity at 415, 322, 300, 145 and 33 Myr ago. Our simulations indicate that the Sun has spent ~60% of its time passing through our Galaxy's various spiral arms.'"
I only read the abstract, but while it proposes a correlation it did not speculate on the exact cause of the extinction. I wonder if passing 'nearer' (I use the term loosely) to higher concentrations of stars might disturb the Oort cloud, sending more comets than normal careening in towards the inner solar system ... or if we might catch stragglers from other stars' own Oort Clouds.
**might** be explained
Isn't that pretty much what "correlation" means?
Assume it were possible to slingshot our sun out of the galaxy into intergalactic space. Would we be better off there, or does the Milky Way offer some sort of protection against whatever's out there (radiation, etc)?
Better known as 318230.
It means every time a mass extinction occurs on Earth, a galactic spiral arm is contructed.
I know that's supposed to be tongue in cheek, but correlation is just another way of saying, we need to look into this with more detail. So if that's your hypothesis and there's correlation between the events, then who am I to judge if you decided to study it with greater detail.
So why are you calling it "rubbish?" They've found a correlation. That's interesting. No-one's claiming to have discovered the mechanism. Correlation is not causation. You seem to have inferred that because someone's found a correlation, they must also be claiming causation.
systemd is Roko's Basilisk.
Before you read too much into this report, remember that a preprint service makes papers available to researchers in the field before the paper has undergone the peer-review process. This allows the results to be circulated amongst other researchers quickly as the peer-review process can takes quite some time.
While not as bad as say having a press conference about discovering "Cold Fusion" before any peer-review only to find that the results could not be duplicated, take the papers contents with a grain of salt as the research has not been peer-reviewed.
You might think of it like the answers you get in the back of a textbook that have usually been done by an author's grad students. Most of them are probably correct, but nobody has gone over them with a fine-tooth comb to verify their correctness.
There has previously been a theory that these mass reoccurring extinctions would have been created by the near passing of a hypothetical star that we would have been unable to detect because it would be on the other side of the Oort cloud.
I suppose that this new finding will debunk that theory for good.
The hypothetical star had been named Nemesis. I know of it only because I ready about it in a novel by Asimov recently.
"We mustn't be caught by surprise by our own advancing technology" -- Aldous Huxley
in other news...many people die in hospitals, therefore hospitals may cause death.
And indeed they do.
http://www.health-care-reform.net/causedeath.htm
http://en.wikipedia.org/wiki/Hospital-acquired_infection
So don't be so quick to dismiss the possibility of causation, simply because it was discovered by correlation.
Falsely assuming no-causation is every bit as much as a statistics induced error as falsely assuming causation.
With correlation you have a reason to look for causation. Without correlation, looking for causation is just shooting in the dark.
Sig Battery depleted. Reverting to safe mode.
Is this some sort of inside joke? A reference to a Time Cube-style crackpot of whom I'm not aware?
Oh dear. I suspect you're serious.
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You cannot wash away blood with blood
... is when we pass through the next one!
http://news.nationalgeographic.com/news/2007/04/070420-extinctions.html Other researchers found that time periods Earth is exposed to large amounts of cosmic rays is correlated with mass extinction events. This is a possible explanation.
We use the most up to date Milky Way model and solar orbit data
in order to test the hypothesis that the Sun's galactic spiral arm crossings cause
mass extinction events on Earth.
That is how the authors of this paper reported their findings in the actual article's abstract. As for how some random Slashdot poster reported this idea, does it really matter? If you are complaining about Slashdot itself and lame editorship on the part of those who review these stories on the Slashdot staff, that is something else entirely and not something to complain about to the paper's authors.
Besides, they claim it is a causation, or that events which somehow happen during those crossings in turn trigger these extinction events. Unfortunately we have a data sample of one solar system to compare against right now to see if there might be any substance to the mechanism.
Well I'm not a scientist but with a little common sense being applied and knowing what we know it makes sense. After all what do we know so far? Well we know there is this HUGE band of rock at the outer edge of our system called the Oort Cloud, there is also another huge band of rocks in the inner system which may have been a failed planet. If going through the arm caused changes to the gravitational fields way out there in the oort cloud it probably wouldn't take much to get one of those chunks moving, after all that is where it is believed all our long term comets came from so there had to be something in the past that got the comets going. So if you look at how big a period we are looking at and how much debris we have in the inner belt the idea that going through the arm may occasionally cause one of those big inner rocks to get flung at us,possibly by being hit by something fling out of the oort? Really doesn't sound too implausible to me.
To me the thing I find really interesting is how many times our friend Mr Jupiter has saved us by being a big giant garbage collector and pulling all this crap into it that could have easily headed our way if it wasn't there. i honestly wouldn't be surprised if it turned out for every extinction event there was probably thousands that didn't happen because Jupiter sucked it up or slung it off in another direction,given how many times we have seen impacts in just the little bit of time we've been able to see that far out.
So I wish them all the luck, maybe if we can find out exactly what events cause these maybe we can avoid it happening to us, as while I doubt we'd see 100% fatalities of the human race one really nasty impact could easily send us back to the dark ages.
ACs don't waste your time replying, your posts are never seen by me.
Do the spiral arms move w/respect to all the stars like some sorta density wave?
That's exactly what the spiral arms are, they can't be the same stars orbiting together in that shape as that would imply a rigid body rotation. The situation where everything moves around together as if it were nailed to a rigid cosmic disc doesn't work because the orbit time of the stars at the centre of the galaxy is less than that of the stars at the edge. This is a consequence of the orbital physics, it's essentially the only way the forces can balance.
So, the stars in the centre whiz around quickly (in cosmological time anyway) whilst the ones at the edge take forever. The spirals are simply areas of higher star density but they are not the same stars all the time. This region does rotate but more slowly than the stars contained within it. So, why are there areas of increased star density? No-one's entirely sure but it seems likely that these are actually regions with higher rates of star formation, with many young, short-lived blue stars.
I've got a novel by John Brunner written in 1982 called The Crucible of Time (), which documents a (very non-human) species through its scientific awakening. Throughout the book they're discovering that their planet is getting closer to a cloud of debris dense enough to massively devastate the surface, possibly shatter the planet. In the end they manage to build enough arks to save the species. The foreward reads:
"It is becoming more and more widely accepted that the Ice Ages coincide with the passage of the Solar System through the spiral arms of our galaxy. ..."
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It's been brought up before, and rather quickly debunked, not because a number of extinctions do occur at the periods of crossing a galactic arm, but rather the numerous other times when extinctions occur outside of the galactic arms, and the times it passes through the arms that the extinction events don't occur.
If you want to see what I'm talking about, just search the science sites about it.
Yes, it is an intriguing idea, but No, it doesn't hold up to scrutiny.
Yeah, it wasn't clear from TFS or TFA what they were talking about, but further down in the discussion:
TL;DR: the Sun orbits the galaxy faster than the spiral arms, and when the solar system passes through gas clouds in the spiral arms, that can send more Ort-cloud comets at the Earth.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
You laugh, but in 50 years the atmosphere gets so hot that it excites the molecules to light speed, at which point it creates a rift in space time that tears back through time, sending hot jets of atmospheric gases ripping through the atmosphere and extinguishing life at periods in the past.
Also, the midwest will be completely covered in 200ft of popcorn.
W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
That doesn't mean what you seem to think it means. "Correlation is not causation" is a statement reminding people that "B causes A" and "X causes A and B" are alternative explanations to "A causes B" when one observes a correlation.
In this case, the only reasonable choice is "galactic orbit causes extinctions" or "the correlation is accidental"; none of the other alternatives are reasonable.
Areas of star formation are more radioactive due to massive blue stars and resulting supernovas when the massive star dies. More star formation happens in the arms.
https://en.wikipedia.org/wiki/Inverted_totalitarianism
A technological regress requires a fragile society not just a sudden jolt.
But we are a fragile society. Without even having to bring up the Idiocracy, the fact remains that we're mostly a society of specialists, dependent on the other cogs in the machine for our survival, stupidly mocking the "preppers" who are really just trying to be generalists. A comet strike could easily disrupt this machine and cause it to grind to a halt.
"Once we've identified and embraced our sickness, we'll have strength...and that's when we get dangerous." - John Waters
I believe a mile wide asteroid destroys everything for about 100 miles and would be killing 200 miles on out. So for example a mile wide asteroid hitting New York kills most everyone in Philadelphia. So let's assume that happens. Note you are picking an almost worst case scenario with the eastern seaboard. We instantly kill say 20m people. GDP would drop a minimum of 10% but the dislocation is bad and say it drops more like 30% instantly (i.e. 27% per capita) That's an incredibly deep depression in the USA. So things are bad. Globally that's going to hit other countries in terms of trade. So UK, China... lose say .3*.2*.25 = 1.5%. We'll make it 2% drop for our trading partners so they have a normal moderate recession.
But... the we know how to fix supply chains. I'd assume we have growth on the order of 8% or more annually from that depressed level easily in the USA and similarly globally as we fix that dislocation. It might even be faster than 8% since 30% is such a depressed level.
A return to the dark ages would be something on the order of a 98% drop per capita that we don't recover from. You can see it is not even close.