Study: Space Rock Impacts Not Random 78
sciencehabit writes When it comes to small space rocks blowing up in Earth's atmosphere, not all days are created equal. Scientists have found that, contrary to what they thought, such events are not random, and these explosions may occur more frequently on certain days. Rather than random occurrences, many large airbursts might result from collisions between Earth and streams of debris associated with small asteroids or comets. The new findings may help astronomers narrow their search for objects in orbits that threaten Earth, the researchers suggest.
Can you say meteor shower ? (Score:5, Informative)
http://en.wikipedia.org/wiki/M... [wikipedia.org]
http://stardate.org/nightsky/m... [stardate.org]
I knew you could
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Statisticians living under light-polluted skies rediscover the phenomenon of "meteor shower" in data, news at 11.
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I've always known that here were a lot more meteors on tuesdays. So now science has finally figured that out, too.
Re:Can you say meteor shower ? (Score:5, Funny)
Can you say filthy arachnids?
Time to invade klandathu! The only good bug is a dead bug I'd always say!
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Thanks comic book store guy!
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Humorous, but that's not what theyre talking about.
They are talking about space rocks large enough to air burst, to actually heat up enough to explode in the atmosphere, such as the Chelyabinsk object.
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If you read the linked news release (which you should, it's very short), they're not talking about meteor showers, they're talking about the large meteors that blew up with a blast energy > 1kt. There were 33 of these detected in the 14 year study period, of which 9 pairs (= 18 of the blasts) occurred within one day of each other. The assumption of independence argument was invalidated at a very high confidence level, claim the authors.
Not stated in the article is whether the 33 blasts had any connecti
bar-room statisticians (Score:2)
It's even worse than that. Going by this quote, they're using it to mean even or homogeneous:
contrary to what they thought, such events are not random, and these explosions may occur more frequently on certain days.
You know, like if a coin comes up heads four times in a row that's "not random".
As to the astronomy bit, this has been known since forever. The major ones have names and can even be predicted. Crapdot FTL.
Re:bar-room statisticians (Score:4, Informative)
It's even worse than that. Going by this quote, they're using it to mean even or homogeneous:
contrary to what they thought, such events are not random, and these explosions may occur more frequently on certain days.
You know, like if a coin comes up heads four times in a row that's "not random".
Actually, that's not a very good analogy. The main pattern that they noticed is clustering of events over long periods of time . It would be more like if you had a coin that was weighted in such a way that it only came up heads about 1 time out of a 100 or something. You flipped it once per day.
According to normal probability, if the only thing that's influencing the coin is just its weight that produces a 1 in 100 chance of heads, the pattern of heads should look relatively homogeneous over a long time span.
Instead, what they tended to find was a lot of clustering of events -- so it would be like going for hundreds of days and then suddenly getting heads on 2 or 3 days in a row, then going again for hundreds of days without any heads again.
In that case, it would be fair to say that there is something else influencing the distribution -- it's not just a "random" distribution you'd expect for a 1 in 100 chance of getting heads. Some other factor is leading to clustering.
Just from looking briefly at the article, it doesn't seem to me that they have a long-enough timespan or enough events to claim strong evidence for a pattern. They basically come up with a 2% stat that this pattern could occur by chance -- sure, that's better than the standard 95% confidence interval for exploratory studies, but there are various statistical features of their study that could be giving them a false-positive here. But it's enough that further study may be warranted.
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So, the same as with meteor showers. Not entire unexpected, i'd think.
Not entirely unexpected, but -- to be clear -- this study is NOT talking about normal meteors in meteor showers (which are presumed to be clustered since they are typically remnants of a comet).
Instead, this study is focusing on LARGER bodies (multi-kiloton impacts), most of which do not have a common origin like bits of a comet. Many scientists assume that they are random hunks of rock from the asteroid belt or some other collection that get perturbed from their normal orbit by interacting with Jupiter
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I predict 100% certain the next roll will not be a 7
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Is, or is not, physics at a macro scale deterministic or not?
Yes and no. Chaos theory concerns itself with problems that are, for all (or most) practical purposes, unpredictable. IOW, these problems are, in principle, deterministic, but in practice, very difficult to solve with any degree of precision. The weather, for example - if we know the starting conditions exactly for every point on the planet (and our models were perfect), we should be able to predict the temperature, wind speed etc exactly for any point in and time, ever, and for any spot on the planet. Unfo
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And, similarly, "chaotic" is not an explanation, either.
Would you accept "inherently impossible to predict any significant length of time ahead"? It's all very well to pick on the reason for the unpredictability (be it quantum uncertainty or extreme sensitivity to initial conditions because of non-linearity) but at a functional level, the outcome is similar: some stuff just can't be predicted in detail long term, and will continue to be like this whatever we do.
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If the input conditions are somewhat more constrained than "the current state of the universe". If the algorithm can be executed on hardware that is any simpler than the physical machine.
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It's a bit worse than that. The Heisenberg uncertainty principle states that you are not allowed by the laws of physics to simultaneously know all the initial conditions with arbitrarily high precision.
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The Heisenberg uncertainty principle states that you are not allowed by the laws of physics to simultaneously know all the initial conditions with arbitrarily high precision.
Perhaps - although this is actually not uncontroversial. There are many things surrounding the interpretation of QM that are not entirely certain - I am aware that every so often somebody comes up with a 'proof' that Heisenberg is more fundamental than simply an effect of our mode of observation. We measure properties of microscopic matter by bombarding it with particles and measuring the statistical outcome of a large number of events; the observation that particles are waves and waves have a minimum 'reso
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But aren't we now finding ways around the Fourier uncertainty? I believe there was a recent Nobel price for advances in microscopy.
... it's about whether QM is correct.
That one is easy: QM is not correct. It is a model - ie. a best approximation etc, but there is almost certainly going to be something, somewhere that is not entirely covered by the model. Isn't that what we all hope for: that we discover something new and amazing?
... if spacetime is quantized (there's a minimum possible distance and a minimum possible time, and all times/distances are integer multiples of these minima) then the wavefunctions wouldn't be continuous...
Ah, but continuity is a matter of topology. If space itself is quantized, the topology would have to be restricted
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You can trivially make large events depend on nuclear decay, thereby breaking macro world determinism.
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One has to accept that, in common usage, the word 'random' simply means 'chaotic' in the above sense.
That doesn't make it acceptable in scientific usage.
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By "random" you mean "as yet unexplained"
Which is the standard use of the word.
Say what now?? (Score:1)
I would have thought this was common sense.
Instead of believing The Giant Flying Spaghetti Monster likes to randomly through rocks at us from up on high, we instead correlate that higher meteor activity is linked to Earths passing through debris fields from existing comet trails, the SAME trails every X amount of years.
Sounds like a story from the 1800's
Now we know what days to hide (Score:2)
Politicians are stars? (Score:1)
Not news! (Score:2)
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That would be our mutual friend, Albert.
http://en.wikiquote.org/wiki/A... [wikiquote.org] (ctrl-F, dice, [enter])
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God plays 3 card monte [wikipedia.org].
What's new? (Score:1)
silly summary, real stats (Score:1)
so they looked at *big* rocks, not small rocks. We know that small rocks often come in showers as comet tails or clouds of assorted crap that we pass through. This study was on the big rocks that are not known to be part of specfic meteor showers like the leonids or whatever. They were previously thought to be fairly random, however the tests they did basically prove that meteor impacts are not a particularly good source of entropy for /dev/random (well, apart from the multiple obvious reasons not to feed t
I'm surprised... (Score:2)
...that this is news?
I'm not an astronomer, but I was pretty sure that the idea that the US passes through periodic 'clouds' of debris was as old as astronomy - how is this substantially different than the Leonid (passing through the debris left by comet Swift-Tuttle)or Perseid meteor shower (passing through the debris left by comet Tempel-Tuttle)?
Personally, I've wondered if some of these could coincide with truly massive volcanic eruptions or meteorite impacts historically, the ones hefty enough to land
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Yeah, my stupid. Not sure what I was thinking when I wrote that.
-1, facepalm.
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It's not the small ones we need to worry about (Score:2)
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It's the bugs, I tell you! (Score:2)
Would you like to know more? [tumblr.com]
Wow! (Score:2)
Scientists discover Space Rock Friday!
Ooh, news. 200 years later... (Score:2)
Dear Slashdot, this has been known for almost 200 years [biodiversitylibrary.org].
And I wouldn't be surprised if Newton also knew this 350 years go but forgot to write it down.
Hold on (Score:4, Informative)
To all the commenters claiming we've already known this for centuries... no, we haven't. There's no reason to presume a priori that large objects occur in "showers" like the smaller (ash particle to pea sized) objects that make up familiar meteor showers. And astrostatisticians are very unhappy with the quality of the statistics in this paper, and they are suggesting the null hypothesis can't be rejecting using better statistical tools: https://astrostatistics.wordpr... [wordpress.com]
Well duh - they can't cover this up. (Score:2)
contrary to what they thought, such events are not random,
Random? Ask the good people on the Rodger Young who were attacked by a lobbed meteor from the Klendathu system, or the near 10 million lives lost in Buenos Aires when that rock landed. Good people. Innocent people. The SkyMarshal is gathering for an all out retaliatory strike to avenge the deaths. It would be an excellent time to step up and serve and become a citizen! Do your part now!
Would you like to know more [starshiptroopers.net]?
http://www.youtube.com/watch?v... [youtube.com]
http://starshiptroopers.wikia.... [wikia.com]
Klytus, I'm bored. (Score:2)
What plaything can you offer me today?
We knew it was no accident! (Score:2)
http://www.theonion.com/articl... [theonion.com]
I've often wondered... (Score:1)
Please, help stamp out postage! (Score:2)
So you're just a little rock drifting in space, perhaps you have a bit of slow elliptical gig with the Sun or some heavy vector from rude encounters with other Astrobumps and potato-lumps. But these vectors have mostly cancelled each other and you're copa-centric with the solar system, just chillin'.
Every now and then you wiggle-woggle as a giant vacuum cleaner that is Jupiter or Mars passes, which leaves you a bit perturbed but its song is so enticing [youtube.com]. You do a little dusting now and then to spruce up th
Of Course: Mondays! (Score:2)
Just when you thought it couldn't get any worse after the weekend along comes a space rock to turn your already bad Monday into something even worse.
Cheers,
Dave