Antarctic Craters Reveal Asteroid Strike 234
dhuff writes "Scientists using satellites have mapped huge craters under the Antarctic ice sheet caused by an asteroid as big as the one believed to have wiped out the dinosaurs 65m years ago."
Maybe....but I'm not buying it (Score:5, Funny)
Re:Maybe....but I'm not buying it (Score:2)
When reading the article, I KNEW that reference would come up multiple times. I was dreading it. I was seriously considering skipping the coments altogether. Well, good sir, imagine my surprise when I saw that A - the expected comment made first post and B - it was actually phrased in a very funny manner.
I tip my hat to you, sir.
Re:Maybe....but I'm not buying it (Score:3, Interesting)
My understanding is that tidal waves are seismic events that travel along the seafloor. They raise the water level only a few feet, and are essentially invisible until they hit shore and start climbing. Since icebergs float, it's not clear how they would suppress a shockwave happening below and around them.
Re:Maybe....but I'm not buying it (Score:4, Informative)
I'm not a specialist in this in any way at all. But maybe this is a good analogy:
Smooth out 2 big comforters on your bed. Kneel on the side of the bed, and sweep your arm under the comforters from one end to the other. It's fairly easy because you only have to displace the comforters right around your arm.
Now put a piece of cardboard as big as your bed between the two comforters. This simulates iceburgs. Now slide your arm through. It will be harder because your arm has to displace a larger amount of comforter as it moves along - the cardboard kind of spreads out the force/displacement that your arm is causing.
That's the only thing I can think of.
Re:Maybe....but I'm not buying it (Score:3, Funny)
I would rather the Angels win than he the world revolving around him...
Re:Maybe....but I'm not buying it (Score:2)
Curious (Score:3, Interesting)
Re:Curious (Score:5, Funny)
The compass industry will go South
Re:Curious (Score:3, Insightful)
Most electronic compasses are based on sensors that are magnetometers. A magnetometer is a device for measuring the intensity of one or more components of the Earth's magnetic field.
I would think that a great deal of electronic devices would have a problem if the earths magnetic field suddenly "flipped."
Cheers,
Erick
Re:Curious (Score:5, Informative)
It doesn't matter what direction the field points, what matters is that there is a magnetic field around the Earth. During the time it takes for the field to flip, the field becomes very weak. That causes two problems. Some animals use the magnetic field for navigation. More importantly, the field is a shield protecting us from cosmic high energy particles. According to a story in the NY Times (covered on
-B
Re:Curious (Score:3, Informative)
Re:Curious (Score:4, Insightful)
Then again it might just be an insignificant fluctuation that happens every billion years or so. We have 150 years worth of data, the Earth is billions of years old, I don't think we're qualified to make assumptions.
Re:Curious (Score:4, Insightful)
-B
Re:Curious (Score:5, Interesting)
So it's always been a bit of a puzzle why there's no correllation between magnetic reversals (where the magnetic field weakens, fades, then reappears with swapped poles) and mass extinctions.
After all, one would think that floods of radiation washing across the Earths surface would be unhealthy, no?
But now it appears that when the magnetic field weakens, the solar wind induces a magnetic field in the ionosphere that's pretty much as effective at stopping high energy particles and cosmic rays as is the original field.
Here's an article about it in New Scientist from a few months ago.
New Scientist [newscientist.com]
But... But ... But... (Score:3, Insightful)
But on a serious note, whether or not this is an ordinary fluctuation is irrelevant in practical terms. If the magnetic field weakens enough to wreak havoc on our expectations (and that could affect much more than just compasses, of course), we should be paying attention to it, whether or not it is "insignificant" in terms of the larger time frame of the universe. Human beings ourselves are likely insignificant in terms of the history of the universe.
Re:Curious - NOT TRUE!!!!!!! (Score:3, Informative)
pm
Re:Curious - NOT TRUE!!!!!!! (Score:2)
Re:Curious - NOT TRUE!!!!!!! (Score:2)
pm
Re:Curious (Score:2)
And, what "qualifications" should be met before we can make these assumptions?
Specifically, why should we disregard a minimual data set when it's all we have to make any kind of decision on?
Which is better - Minimal data which indicates distinct possibilities and problems to plan against, or - Ignore anything but bullet-proof data and act blindly?
Put another way, let's assume that you
Re:Curious (Score:2, Insightful)
For all we know our magnetic feild could have been at it's strongest ever 150 years ago and now it's leveling off to normal levels. Or perhaps it's dipping right before a major surge in magnetism. Maybe it's plumeting like a stone. The fact of the matter is we don't know
Re:Curious (Score:3, Insightful)
Re:Curious (Score:3, Informative)
That of course doesn't count because humans didn't record it, right?
Re:Curious (Score:2)
Re:Curious (Score:2)
Not signing on with bible crowd, but ...... (Score:2)
for a "short" while near the poles and they
"completely" melted we would see hundreds of feet
rise in sea levels world wide
According to bible it rained for forty days and
forty nights and I am not sure how long it took
to "drain off"
My guess would be as it rained in some parts,
it fell as snow in others , and the volcanic
activity subsided
That is a scientific guess at a situation that
may or may not have happened
For that much water to fall as precipitation
would
Re:Not signing on with bible crowd, but ...... (Score:2)
Re:Not signing on with bible crowd, but ...... (Score:2)
In the past I think it was more so
I also think the so called flood just flooded "most" of
the earth, not all of it, because even in theory the Ark
ended up on mount Arrarat in Turkey
Thousands of feet of water just sounds too preposterous to me,
there is not that much water on the planet and at the time
that mountain may not have been as tall either
Moutains rise, and they fall, maybe it has been on the rise,
as for the geology of it I have no
Re:Not signing on with bible crowd, but ...... (Score:3, Informative)
Re:Curious (Score:2)
I was listening to a "Living on Earth" episode recently where some scientists were studying a certain migratory bird (can't recall which (maybe terns?). Apparently this bird calibrates what it senses as the magnetic field with where the sun sets each night.
For the experiment, the birds were kept exposed at sunset to a magnetic field that was 90 degree off what it's supposed to be. When they let the birds out after dark, they flew the wrong direction by
Parent is ignorant or trolling? Hard to tell. (Score:3, Insightful)
Magnetism has nothing to do with the direction in which water flows in a drain. That would be the rotation of the planet.
Does the magnetic field being reversed actually affect anything important?
Yes.
Things like radiation reaching the planet's surface, stuff like that.
Re:Parent is ignorant or trolling? Hard to tell. (Score:5, Informative)
Magnetism has nothing to do with the direction in which water flows in a drain. That would be the rotation of the planet.
And for all reasonable-sized drains (such as the ones you have at the bottom of your bathtub), the Earth's rotation has a completely-negligible effect on the outflow. The notion that the Coriolis force causes water to drain in opposite directions, in the Northern and Southern hemispheres, is a fallacy.
To see why this is so, consider the so-called Rossby radius of deformation [tamu.edu], defined as the ratio between wave speed and rotation frequency. This quantity is the length scale at which the Coriolis force begins to have an appreciable effect on disturbances in a fluid in a rotating system. Plugging in the appropriate values for water waves in a bathtub on the rotating Earth, you find a Rossby radius of around 20km. This is four orders of magnitude larger than the scale of the bathtub, indicating that the influence of the Coriolis force on draining water will be almost non-existant.
Re:Parent is ignorant or trolling? Hard to tell. (Score:2)
Re:Parent is ignorant or trolling? Hard to tell. (Score:2)
The one we're talking about, smartass. Water going down drains.
My response was an honest question; I wasn't sure whether you were talking about rotational effects in large bodies of fluid (such as weather systems); or rotational effects in draining bathtubs, which don't exist. Water going down drains in different directions is a fallacy, for which there is no observational evidence that requires explanation.
Re:Parent is ignorant or trolling? Hard to tell. (Score:3, Informative)
WHAT MAKES THE WATER ROTATE WHEN IT GOES DOWN THE DRAIN?
Conservation of angular momentum. As the distance between a given fluid element and the drain gets smaller, the angular velocity of the element must increase, to ensure that angular momentum is conserved.
Is this simple enough for you now?
Re:Parent is ignorant or trolling? Hard to tell. (Score:2)
Obnoxious, dismissive, arrogant and a science geek -- how do you stay single?
Ah, an ad hominem! The sure sign of an argument just lost...
Re:Parent is ignorant or trolling? Hard to tell. (Score:2)
Whatever (very) small rotation there was when you unplugged the drain continues existing. As the water comes closer to the center of the drain, it moves in smaller and smaller circles. It turns faster because the tangential velocity around the circle is the same. Smaller circle means faster rotation. That's what's called "conservation of angular momentum". If the water had been absolutely, un-fucking-believable still to begin with, there would be no
Re:Parent is ignorant or trolling? Hard to tell. (Score:2)
Actually, I just tried that... and each time it swirl
Re:Parent is ignorant or trolling? Hard to tell. (Score:3, Funny)
I take it you don't watch The Simpsons...
Bart: "Do the toilets go backwards in here?"
U.S Embasy guy: "No. To combat home sickness, we've installed a device that makes them swirl the correct American way."
*Flushes toilet. Machine kicks in and water swirls the other way*
Homer (weeping, singing): "Sweet land of liberty..."
Re:Parent is ignorant or trolling? Hard to tell. (Score:2)
For those who don't know, it is a clock with a horizontally rotating flywheel, that you never need to wind. It works provided that you are within a certain lattitude - too close to the equator/poles and it won't work. Very delicate 19th century design - the ones you get in the shops today are immitations and are battery powered.
So the Coriolis force can have an effect on very small objects just a few inches in diameter - enough to power a clock by steali
Re:Parent is ignorant or trolling? Hard to tell. (Score:2)
So the Coriolis force can have an effect on very small objects just a few inches in diameter - enough to power a clock by stealing energy from the earth's rotation.
I'd never heard of this -- sounds interesting! But my original remarks were made in reference to disturbances of a fluid in a rotating system, such as water draining from a bathtub on the Earth's surface. A flywheel is a totally different kettle of fish.
Re:your sig (Score:2)
That would be (i): I'm whining about the attacks made on the capabilities/intellect of Indians by /. posters, apparently disgruntled that their jobs have been outsourced. These attacks rather forget that the Indian textile industry was destroyed in the 18th/19th centuries by forcible outsourcing to Europe and the USA.
Re:your sig (Score:2)
(Just wait until after November and then listen to W. complain.)
By the way, I have lots of students from India. They rarely complain; they just work hard, do well, get jobs in areospace (or other industries) and enjoy life. (One student is almost done with his PhD in EE and has already started working on a PhD in my department (Math). He will be able to "write his own ticket". (He has already applied for a ("real" - not software) patent.) I
Re:your sig (Score:2)
(Just wait until after November and then listen to W. complain.)
Fingers crossed!
Is it different for people who remain in India?
I don't know; my experience is much like you, in that I'm nothing but impressed with the Indian students (and Pakistani, and Bangladeshi) which I see passing through -- in my case, studying Physics and Astronomy.
Still can,t tell, but I was ignorant! :( (Score:2)
Dear god, if something is repeated enough...
Well, I'm off to filling my tub and experimenting for myself, thanks.
Re:Still can,t tell, but I was ignorant! :( (Score:3, Insightful)
Well, I'm off to filling my tub and experimenting for myself, thanks.
The best possible attitude toward science -- "show me!". Have fun in your tub!
Re:Curious (Score:3, Funny)
Re:Curious (Score:2, Informative)
We also don't know how long the reversals take to complete, and that's the worrisome aspect. If it happens fairly quickly, there wouldn't be
Re:Curious (Score:2)
What are the odds? (Score:2, Interesting)
Prof Van der Hoeven said: "The extraordinary thing about this meteor strike is that it appeared to do so little damage. Unlike the dinosaur strike there is no telltale layer of dust that demonstrates the history of the event. It may have damaged things and wiped out species but there is no sign of it."
Cheers,
Erick
Re:What are the odds? (Score:2)
Yeah, what do you expect when you vaporize hundreds of cubic miles of ice? a few extra inches of rainfall... At best, it might show up in the sand layers of any deserts that existed back then. For the most part, however, I'd expect the evidence to be washed away by itself.
Re:What are the odds? (Score:2)
Well, if it wasn't for the belief that (a href="http://education.guardian.co.uk/higher/scie n ces/story/0,12243,1286205,00.html">from the article)
Your might be worth more consideration. As it is, I'm guessing that more ice in Antarctica at the time is more likely t
Re:What are the odds? (Score:2)
That can't be! It was covered with ice when humans discovered it. Don't you know that the Earth never changed at all until humans came along and caused global warming? Geesh, geeks these days!
No damage? (Score:2, Informative)
One thing that did happen at exactly the same time was the reversing of the Earth's magnetic field. There is no other explanation as to why this took place and Prof Van der Hoeven believes it was caused by
Re:No damage? (Score:2)
Well now... (Score:5, Interesting)
Have the nuk-lear worryworts made sure that we haven't even researched the possibilities? Best I've ever seen is the occasional schematic of an orion-type starship from decades ago. Screw Ion-Drives. Let's give some money to the big engines...
Re:Well now... (Score:5, Interesting)
Re:Well now... (Score:2, Interesting)
Re:Well now... (Score:5, Interesting)
So yes, they would have to time them perfectly, but that wouldn't be too difficult as it's a problem they've already figure out how to solve when constructing the devices in the first place.
How hard can it be? (Score:2)
So, you are saying that nuclear weapon design is almost as complicated as dual-CPU motherboard design?
Re:Well now... (Score:2)
Re:Well now... (Score:5, Interesting)
Re:How Exactly precise must they be timed? (Score:2)
([Distance between warheads] / c ) = [precision required]
0.05 km / 299,792.458(km/s) = 1.6678204759907602478778835723746e-7 s
Someone please check my math. Its sometimes as bad as my grammer.
Re:Well now... (Score:3, Funny)
No layer of dust? (Score:5, Interesting)
The extraordinary thing about this meteor strike is that it appeared to do so little damage. Unlike the dinosaur strike there is no telltale layer of dust that demonstrates the history of the event.
It ploughs through millions of tonnes of ice and snow, then leaves no layer of dust... d'you think it might have, I dunno, melted or something?
More information at The Scotsman [scotsman.com], btw.
Stay away... (Score:5, Funny)
Re:Stay away... (Score:2)
Re:Stay away... (Score:3, Funny)
Hail (Score:2, Funny)
Hah! Take that Karma!
Interception (Score:5, Insightful)
Obviously, statistically the chance of an individual being killed by a major meteor strike is fairly low, perhaps lower than that of being killed in a terrorist attack and much lower than that of being killed on the roads. But it's the meteor strike that has the potential to kill perhaps 99% of the human race, and this latest evidence seems to suggest that the frequency of such impacts is higher than expected.
Re:Interception (Score:3, Insightful)
Re:Interception (Score:2, Interesting)
Re:Interception (Score:2)
impact reversing magnetic field? doubtful (Score:5, Interesting)
And why even compare this 780K yr old impact to what might've done the dinosaurs in 65m yrs ago? It just would confuse people with poor reading skills (*cough* slashdot readers) and lead them to associate this 780K yr old impact with the extinction of the dinasaurs.
Also, the article attemps to explain why the 65m yr old impact would've caused climactic change whereas the 780k yr old impact would not -- I didn't quite understand their argument of why the older impact caused dust clouds leading to extinction while the newer impact did not -- was it because of the composition of ice vs rock?
Re:impact reversing magnetic field? doubtful (Score:2)
I wouldn't think so. Antarctica is actually a continent so there should have been dust. Although it makes sense that the dust may have settled differently because of the climate.
Ob Simpsons Reference (Score:2)
Pole reversal (Score:2)
Between the impact damage and the pole reversal, it would be interesting to see if corresponding evidence of the strike would be found at/near the North Pole, under the theory that strikes have large effects on the region opposite strikes on the Earth.
65 milli years ago? (Score:5, Funny)
The dinosaurs were wiped out on July 28 2004?
Re:65 milli years ago? (Score:2)
You really are missing something...... (Score:5, Insightful)
That impact would have crushed mountains and created enormous amounts of dust from them. The 780k impact hit a huge block of ice and snow, i.e. no dust to scatter in the first place. I really doubt it would have affected any land life at all, antarctica being so far from land inhabited by anything more than penguins and stuff. Ocean life probably got pretty roughed up at least close to the impact.
Re:You really are missing something...... (Score:2)
Re:You really are missing something...... (Score:3, Insightful)
Re:You really are missing something...... (Score:2)
Re:You really are missing something...... (Score:3, Interesting)
Don't we pass through an asteroid belt about twice a year? I seem to remember something on Discovery Channel or on an astronomy site that named the belts. I'll revisit the sites, but in the meantime... Aren't there all sorts of odds (in favor of nature/against human populations) that could see us or the Earth being hit once in a while more frequently than we've recorded or claimed? If not, then...
What are the chances (hi or lo) that we pass through some metallic or iced or
Oh my (Score:2, Funny)
Re:Oh my (Score:2)
Human evolution (Score:3, Interesting)
Re:No (Score:2)
Oh great, one more reason I can't get laid...
Location? (Score:3, Insightful)
Homo Erectus was there (Score:4, Interesting)
At that point our hominid ancestors were strolling around southern Africa. By then we had stone tools and the occasional use of fire. That's really recent in a hominid lineage that goes back, what 6 million years? They lived through a 3-7 kilometer asteroid impact! Can you imagine?
Good thing it didn't land a few thousand miles to the north...
Several questions (Score:3, Insightful)
However this report raises a lot of questions that it doesn't answer.
First of all, they seem to be talking about a single strike, but they first talk about "the crater" and then later "the holes" and "the craters." Are we talking about one crater or many? Did the person who wrote the article typo, or are the scientists being that unspecific?
Second of all, wasn't the Antarctic continent still near the south pole 780k years ago? That seems to mean that either the meteor hit at a very extreme angle, or it was _far_ out of the elliptic. In either case, it would be a very rare occurance.
On the other hand, magnetic reversals are _not_ a very rare occurance, they happen about once every 700,000 years. Why is he assuming that the very rare occurance caused the frequent and mostly regular occurance? It seems much more likely that it was just a coincidence. "There is no other explanation as to why this took place" yeah, and there is no other explanation for the other several _hundred_ nearly identical events either, because we haven't figured out why they happen yet! So is he proposing that Antarctica gets hit by a giant meteor about every 700k years like clockwork?
Finally exactly how "huge" are these craters, and what were the climatic conditions 780k years ago? If the climate was similar and Antarctica was near the south pole and covered with ice, wouldn't a "huge" strike have melted/dispersed quite a lot of the ice and caused ocean levels to rise?
AVP (Score:2)
EnvironmentalistsTake Note... (Score:2)
Environmentalists take note, we now have the solution to your biggest fears of Global Warming. We just need to refine the technique a bit.
Stopping asteroids. (Score:2)
Second Impact ? (Score:2)
Am I the only one who didn't immediately think of Second Impact [wordiq.com] the disaster in Neon Genesis Evangelion that destroyed Antarctica and killed half the worlds population. But of course the 'impact' story was a fictional explanation for an event in a fictional anime ... fiction within fiction .. is that like a double negative for reality. Must be, the proof is right there under the ice ... heh heh.
It's under ice? (Score:2)
Asteroids? (Score:4, Funny)
Re:Sounds suspicious (Score:2, Funny)
Not at all, but if they claimed the dinasaurs built an earth ship to drill to the core and detonate 4 nuclear bombs, I'd be suspicious.
Re:Sounds suspicious (Score:2, Interesting)
The ice would definitely prevent large tsunami. I have seen even the lightest coating of snow tame the rough north atlantic.
As far as the meteor causing magnetic pole reversal, I don't see how. The earth's magnetic fields originate in the spinning iron core. Perhaps disturbing the spin slightly might help trigger a field reve
Don't be silly; it happened (Score:3, Funny)
Dim moderators! (Score:2)
Jeesh, RTFA!