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Skydiver meets meteorite
April 3, 2014 10:28 AM   Subscribe

Norwegian skydiver nearly struck by meteorite. Although Helstrup is still not completely convinced that it was indeed a meteorite that flew past him, the experts are in no doubt. “It can’t be anything else. The shape is typical of meteorites – a fresh fracture surface on one side, while the other side is rounded,” said geologist Hans Amundsen, “It has never happened before that a meteorite has been filmed during dark flight; this is the first time in world history.”

First video @ 2:41 shows a composite photograph of the passing meteorite.
posted by davidpriest.ca (94 comments total) 38 users marked this as a favorite

 
I hope this is not a Norwegian April Fool’s day prank.
posted by davidpriest.ca at 10:29 AM on April 3


(Also, I suppose it is now a meteorite, but at the time of filming was a meteor. Or a meteoroid. Whatever.)
posted by davidpriest.ca at 10:31 AM on April 3 [1 favorite]


Dang. Remarkable and unspectacular at the same time.
posted by postcommunism at 10:36 AM on April 3 [8 favorites]


Would it have a high iron content? Would a metal detector be useful?
posted by tommasz at 10:39 AM on April 3


Sure, but you'd have to figure out it's trajectory and where it landed. I'm thinking that would be pretty difficult from the altitude where it was captured on video.
posted by Big_B at 10:44 AM on April 3


If it had struck, and killed him, it would have been another world first: a documented , verified account of any person being killed by a meteor.
posted by WaylandSmith at 10:48 AM on April 3 [2 favorites]


Wow! Such an amazing coincidence.
But yeah, there is something about the style of the program that makes you think it's a really strange prank.
"you were one minute from being cut over - hahaha"
posted by mumimor at 10:53 AM on April 3


Extraordinary claims require extraordinary evidence. I say fake.

If there were a meteor that exploded to provide a rock of that size, it would have been very evident as a bright flash widely visible in daylight over hundreds of square miles.
posted by JackFlash at 10:54 AM on April 3 [1 favorite]


i was nearly eaten by a shark once.
posted by bruce at 10:54 AM on April 3 [1 favorite]


Can't help imagining somebody somewhere up there going 'Dang!-- Missed!'
posted by jamjam at 11:00 AM on April 3


I hope this is not a Norwegian April Fool’s day prank.
It's posted April 3rd on the Norwegian state media, both the English and Norwegian versions. It's not an April's Fool.
Extraordinary claims require extraordinary evidence.
I guess that's why the Norwegian Museum of Natural History has been investigating it for 1½ years before making the announcement. It's also worth noting that the skydiver himself isn't convinced.
posted by brokkr at 11:08 AM on April 3 [8 favorites]


But yeah, there is something about the style of the program that makes you think it's a really strange prank.
"you were one minute from being cut over - hahaha"


Eh, based on my experience with extended-family gatherings, that's just the Norwegian sense of humor...
posted by stenseng at 11:09 AM on April 3 [2 favorites]


Blog post from the "Norwegian Meteor Network" including composite images, graphs and other visualizations.
posted by brokkr at 11:12 AM on April 3 [2 favorites]


While it's possible it could have been faked by throwing a stone from an airplane, the behavior pattern doesn't look very hoaxy -- he went to scientists to ask them about it, not the media, and it's been a couple of years of investigation. Plus the only real payday opportunity would be selling the stone, which brings up the risk of a fake being revealed. If it was "after two years, stone is found, up on ebay!" I'd be very suspicious, but as of now there doesn't seem to be any reason to presume fake. Though obviously the consideration always has to be kept in play.
posted by tavella at 11:16 AM on April 3


The woman's smile was infectious for me. My cheeks were hurting by the time I was done watching this.
posted by Our Ship Of The Imagination! at 11:19 AM on April 3 [3 favorites]


If I had a friend killed like this, I'd be inclined to say, well, this is sad, but his number was just up.
posted by thelonius at 11:21 AM on April 3 [5 favorites]


brokkr: "Blog post from the "Norwegian Meteor Network" including composite images, graphs and other visualizations."

Wow. Okay they've done a lot of analysis on this and trying to find it but haven't located it.
posted by Big_B at 11:28 AM on April 3


i was nearly eaten by a shark once.


A Møøse once bit my sister...
posted by TheWhiteSkull at 11:35 AM on April 3 [17 favorites]


Would it have been deadly, had it hit him? This low in the atmosphere, it would have been moving at terminal velocity, which isn't that fast for a small rock. Plus, you can subtract the skydiver's speed from that, which was likely to be substantial (even with his parachute out). Also, he was wearing a helmet. However, if he got knocked out, the landing might be deadly, even with his chute open. And I'm not sure what kind of damage it would have done to his parachute (perhaps punching a hole in the chute, or taking out some of the cords).

Talk about crazy luck seeing it, and crazy luck not being hit.
posted by Mitrovarr at 11:38 AM on April 3


I predict this will soon start showing up on sidebars all over the web, with a headline something like "Two Norwegians jump out of an airplane…then something really crazy happens!"
posted by TedW at 11:43 AM on April 3 [1 favorite]


They thought the meteorite was a meteor but it wasn't, so it's a meteorong.
posted by mule98J at 11:47 AM on April 3


A meteorite once bit my sister.
posted by blue_beetle at 11:49 AM on April 3 [1 favorite]


This is a really cool story and I could watch enthusiastic Norwegian lady all day.


But FFS, can we not do the Monty Python thing simply because it's in Norway? Can we just not do that?
posted by Legomancer at 11:50 AM on April 3 [7 favorites]


I'm trying to do a back of the envelope calculation on the likelihood of this happening:

The surface of the Earth is about 500,000,000,000,000 sq meters.

Let's say the field of view in which you could record a meteor like this is 200 sq meters.

So if he were standing on the ground, the chances of this meteor falling where he could film it like this is about 1 in 2,500,000,000,000.

Meteor strikes of this size are pretty rare-- maybe once or twice a day?

Let's say an average skydive lasts 5 minutes. For simplicity, I assume that if the meteor strikes the Earth any time during that 5 minute period in that 200 sq meter field of view, he films it.

If I've got this right, the chances of filming a meteor during any random skydive is on the order of 1 in 350,000,000,000,000.

I want to believe, but this seems statistically impossible.
posted by justkevin at 11:51 AM on April 3


But FFS, can we not do the Monty Python thing simply because it's in Norway? Can we just not do that?

Nø.
posted by The Bellman at 11:52 AM on April 3 [22 favorites]


My sister once hit a moose with her Meteor.
posted by weapons-grade pandemonium at 11:57 AM on April 3


Enough norientalism already.
posted by klue at 12:07 PM on April 3 [2 favorites]


ha haha, no, norientalism would be if we somehow expected death metal music and expensive lager to somehow figure into this story.
posted by C.A.S. at 12:12 PM on April 3 [2 favorites]


If there were a meteor that exploded to provide a rock of that size, it would have been very evident as a bright flash widely visible in daylight over hundreds of square miles.

Why do you think it would have to be a fragment of a larger meteor exploding? Meteoroids larger than this one hit the earth on a daily basis, without widely visible daytime explosions.

I believe only the very large meteors explode. Smaller ones just slow down to terminal velocity and then just fall to earth normally. This one sounds like it's roughly the size of a pineapple, so its terminal velocity would something like 150-250 mph, depending on how aerodynamic it is.

Would it have been deadly, had it hit him? This low in the atmosphere, it would have been moving at terminal velocity, which isn't that fast for a small rock. Plus, you can subtract the skydiver's speed from that, which was likely to be substantial (even with his parachute out).

The rock was going over 150 mph. With a parachute open, skydivers fall less than 20mph. You can see in the video it falls past him quite quickly.

I think the only way he could have survived being struck is if it hit a body part he doesn't really need that badly, like an arm or something.
posted by aubilenon at 12:16 PM on April 3 [1 favorite]


If I've got this right, the chances of filming a meteor during any random skydive is on the order of 1 in 350,000,000,000,000.

You really can't use statistical inferences that way. The odds that you would be breathing any of the specific oxygen molecules you happen to have in your lungs right now out of all the oxygen molecules in the world were astronomically low--that doesn't mean it's statistically impossible for you to breathe, however.
posted by yoink at 12:17 PM on April 3 [10 favorites]


1 in 350,000,000,000,000 isn't statistically impossible, it's statistically very very extremely unlikely but possible. In the article they estimate that you're more likely to win the national lottery three times than film a meteorite falling.
posted by brokkr at 12:18 PM on April 3


You could have three skydivers experience this and film it on three consecutive days and it would still be just as statistically unlikely an occurrence for each of them, no? It would be fantastically more unlikely that three in a row happened like that, but still 1 in 350,000,000,000,000 for each one.
posted by jason_steakums at 12:24 PM on April 3


I'm pretty sure that's some 747 turd.
posted by phaedon at 12:27 PM on April 3


This is reasoning after the unpredicted, unanticipated fact. Such probability calculations are meaningless. Every specific event drawn from a continuous distribution has an probability of occurrence of zero. Yet all events are specific. You can calculate probabilities of this sort only if there is a finite number of non-events. But without prior specification of what event you think highly unlikely to happen, the number of non-events is infinite. This is a great case of shit happened. Which doesn't detract from it one bit.
posted by stonepharisee at 12:28 PM on April 3 [5 favorites]


If I've got this right, the chances of filming a meteor during any random skydive is on the order of 1 in 350,000,000,000,000.

There seem to be about 3 million skydiving jumps a year, which leaves us with a one in a hundred million chance that someone would be nearly hit by a meteoroid in a given year.

That's pretty rare, yeah. Hardly statistically impossible. But also consider there's an enormous number of similarly improbable things that you could do the same analysis.
posted by aubilenon at 12:29 PM on April 3


But FFS, can we not do the Monty Python thing simply because it's in Norway? Can we just not do that?

We apologise for the fault in the subtitles. Those responsible have been sacked. Mynd you, møøse bites Kan be pretti nasti...
posted by briank at 12:33 PM on April 3 [13 favorites]


That is super cool, and it's fascinating to contrast the tone of the Norwegian tv show (hee hee, omg wow hilarious close call) with what it would be in the US (furrowed brow and serious scary music, how did it change your life to Nearly Die, here's a hanky; what should other people do to avoid this terrible heretofore unrecognized threat).
posted by LobsterMitten at 12:33 PM on April 3 [8 favorites]


You really can't use statistical inferences that way. The odds that you would be breathing any of the specific oxygen molecules you happen to have in your lungs right now out of all the oxygen molecules in the world were astronomically low--that doesn't mean it's statistically impossible for you to breathe, however.

That's not really a correct comparison, because here we're talking about a very unlikely and remarkable event. Any particular outcome of the lottery is equally unlikely, but if the result tomorrow were 1 2 3 4 5 6, that would also be remarkable and possibly show up on the front page of Metafilter.

That's pretty rare, yeah. Hardly statistically impossible. But also consider there's an enormous number of similarly improbable things that you could do the same analysis.

I use the phrase "statistically impossible" as a figure of speech-- anything that has a statistical probability is technically possible. But you have a good point that lots of things happen on our planet, unrelated to skydiving or astronomy, so it's fair to say, "Given all the stuff that gets filmed, what are the odds that something this remarkable will be filmed?"
posted by justkevin at 12:38 PM on April 3


If it had struck, and killed him, it would have been another world first: a documented , verified account of any person being killed by a meteor.

However, Ann Hodges of sunny Oak Grove AL was struck in the side by a meteor that fell through the roof of her home in 1954. She had a nasty bruise but was okay.
posted by ROU_Xenophobe at 12:39 PM on April 3 [3 favorites]


That settles it. I am never going to try skydiving.
posted by Flashman at 12:43 PM on April 3 [3 favorites]


Ann Hodges of sunny Oak Grove AL was struck in the side by a meteor that fell through the roof of her home in 1954.

You are referring to the Sylagauga meteorite. Note this this meteorite was grapefruit sized and was visible across three states and included a sonic boom.
posted by JackFlash at 12:54 PM on April 3


Would it have been deadly, had it hit him? This low in the atmosphere, it would have been moving at terminal velocity, which isn't that fast for a small rock. Plus, you can subtract the skydiver's speed from that, which was likely to be substantial (even with his parachute out).
The blog post I linked to has some calculations. They estimate the size and mass of the rock to be probably 12 by 16 cm and 4.6 kg, and it passes the skydiver at a distance of approximately 4.6 m at a speed of 280 km/h (lower bounds 7 by 9 cm, 0.9 kg, 2.5 m, 220 km/h ; upper bounds 18 by 24 cm, 20 kg, 6.5 m, 400 km/h). The skydiver's speed is no more than 100 km/h.

And as they write: "Hadde Anders blitt truffet, kunne det lett ha gitt et dødelig utfall og noe forvirring for dem som skulle etterforske ulykka!" ("Had Anders been hit, the result could easily have been both fatal and quite confusing for the people investigating the accident!")
posted by brokkr at 12:59 PM on April 3 [4 favorites]


Maybe it was wrapped up in his parachute ahead of time . . . when it opened up, out pops the rock . . .
posted by fimbulvetr at 1:18 PM on April 3


"Had Anders been hit, the result could easily have been both fatal and quite confusing for the people investigating the accident!"

Imagine that meeting at the (N)NTSB: "Uh, based on the pattern of his wounds, it appears the victim was blown in half at five thousand feet by a slow-moving cannon ball fired from above? Or something?"

(Of course they'd be using the metric system so they'd actually say, "at one thousand five hundred twenty-four meters.")
posted by The Tensor at 1:59 PM on April 3


Hot damn!
posted by homunculus at 2:03 PM on April 3


Skydiving might be inherently dangerous after all. Don't tell my mother.

I was under the impression that inbound meteors had extreme velocities; with speeds on the order of Mach 27+, combustion, sonic booms, &c, &c .... so I do harbour serious doubts about this story, notwithstanding the charming interlocutor and 'evidence.'
posted by GhostRider at 2:10 PM on April 3


("Had Anders been hit, the result could easily have been both fatal and quite confusing for the people investigating the accident!")

The CSI: Oslo episode practically writes itself!
posted by Atom Eyes at 2:12 PM on April 3 [2 favorites]


That's not really a correct comparison, because here we're talking about a very unlikely and remarkable event. Any particular outcome of the lottery is equally unlikely, but if the result tomorrow were 1 2 3 4 5 6, that would also be remarkable and possibly show up on the front page of Metafilter.

Exactly. And if someone said "and the odds against that are one in 999,999 therefore it can't possibly have happened by chance" they would be making much the same statistical error you made about this meteor.
posted by yoink at 2:13 PM on April 3 [4 favorites]


My sister once hit a moose with her Meteor.

How 'bout a Winnebago? Hell, have a whole herd o' Winnebagoes, we're just givin' 'em away . . .
 
posted by Herodios at 2:15 PM on April 3 [1 favorite]


Ann Hodges of sunny Oak Grove AL was struck in the side by a meteor that fell through the roof of her home in 1954

Poor woman. Not only bruised from outer space but tended by a werewolf disguised as a doctor.
posted by glasseyes at 2:17 PM on April 3 [2 favorites]


Poor woman. Not only bruised from outer space but tended by a werewolf disguised as a doctor.
Haha, yeah, I didn't see that at first
posted by mumimor at 2:32 PM on April 3


Another near miss: in 1949, a meteorite came through the roof of a hotel in my family's home village (Beddgelert in Wales). No injuries, but a very puzzled hotel owner.

(http://www.jonesbryn.plus.com/wastronhist/meteorites.html)
posted by 43rdAnd9th at 2:45 PM on April 3 [2 favorites]


The CSI: Oslo episode practically writes itself!

Tun! Tun!*


* …fisk
posted by zippy at 2:57 PM on April 3 [1 favorite]


GhostRider: "I was under the impression that inbound meteors had extreme velocities; with speeds on the order of Mach 27+, combustion, sonic booms, &c, &c .... so I do harbour serious doubts about this story, notwithstanding the charming interlocutor and 'evidence.'"

In the upper atmosphere yes, but in the lower atmosphere the drag is much greater:

Due to atmospheric drag, most meteorites, ranging from a few kilograms up to about 8 tons (7,000 kg), will lose all of their cosmic velocity while still several miles up. At that point, called the retardation point, the meteorite begins to accelerate again, under the influence of the Earth’s gravity, at the familiar 9.8 meters per second squared. The meteorite then quickly reaches its terminal velocity of 200 to 400 miles per hour (90 to 180 meters per second). The terminal velocity occurs at the point where the acceleration due to gravity is exactly offset by the deceleration due to atmospheric drag.
posted by Big_B at 3:03 PM on April 3 [1 favorite]


(Also, I suppose it is now a meteorite, but at the time of filming was a meteor. Or a meteoroid. Whatever.)

"The meteorite is the source of the light
And the meteor's just what we see
And the meteoroid is a stone that's devoid of the fire that propelled it to thee"
posted by hydrophonic at 3:57 PM on April 3 [10 favorites]


Another near miss: in 1949, a meteorite came through the roof of a hotel in my family's home village (Beddgelert in Wales). No injuries, but a very puzzled hotel owner.

From your link, the Pontllyfni meteorite, significantly smaller than the purported meteorite in Norway, was observed as a fireball clearly visible in the noon time sky. The sonic boom caused the villagers to rush out into the streets. Just like the one in Alabama described above.

Objects of this size don't just sneak in. They are big, bright, loud events that are observable over wide areas.

Look, I appreciate the endearing childlike naiveity of some mefites, but how many of these youtube hoaxes do we have to go through before people develop a little bit of logical skepticism.
posted by JackFlash at 3:59 PM on April 3


klue: Enough norientalism already.

I don't really mind the Monty Python references, though as an Icelander I understand the annoyance in being exoticized (ask me about elves... actually, don't ask me about elves) but as long as we're throwing around terms, I believe that the analogous term for orientalism for people from the Arctic and Subarctic regions of the world is “borealism" (though it is rarely used).

posted by Kattullus at 4:26 PM on April 3 [5 favorites]


I believe that the analogous term for orientalism for people from the Arctic and Subarctic regions of the world is “borealism" (though it is rarely used)

Oh, come now, that's a bit harsh. Some of you chaps are quite interesting, you know.
posted by yoink at 4:33 PM on April 3


Coming up next, Meteor Week, on The Discovery Channel.
posted by valkane at 4:35 PM on April 3


I do hope that "like finding a rock in Norway" replaces the old needle-in-a-haystack idiom.

I've been to Norway. It has a lot of rocks.
posted by Devonian at 4:41 PM on April 3 [4 favorites]


I don't care one way or the other, Kattullus. Poor pun attempt is all. If anything, NRK is to blame: you'd think the news worthy event was the close call with a meteorite, not the nationality of the skydiver.
posted by klue at 4:45 PM on April 3 [1 favorite]


Historically, the parachutist has usually been inside the Meteor.
posted by charlie don't surf at 5:00 PM on April 3


Happily, there is no Red Bull logo.
posted by yoga at 5:30 PM on April 3 [2 favorites]


i was nearly eaten by a shark once.

Fish are friends, Bruce, not food.
posted by maryr at 6:03 PM on April 3 [1 favorite]


Exactly. And if someone said "and the odds against that are one in 999,999 therefore it can't possibly have happened by chance" they would be making much the same statistical error you made about this meteor.

I think you're getting hung up on my using the phrase "statistically impossible." Like a magician correctly predicting the results of the lottery, it could happen but is so very unlikely we assume that's not what actually happened.

I'm saying that this event is so astronomically improbable, that it suggests there is a more likely explanation.
posted by justkevin at 6:05 PM on April 3


NRK is really bringing it to the internets this week.
posted by maryr at 7:13 PM on April 3


Once upon a time, when I was about 14, I was walking back from a friend's house on the military base in the middle of the day. Out of nowhere, roughly the middle of the street, a rock just smashes into the ground. I look around, sure some asshole friend of mine has just lobbed a rock at me. But, it was oddly quiet. And it just didn't seem like a rock that had been lobbed. It was too fast and too directly at the ground. The base was an Air Force training base where there were omnipresent jets flying overhead. I wondered if a pilot tossed something out of a window. But, that wouldn't happen. You don't lob things out of F4 windows. And even if you could, you'd lose your job and livelihood right quick. But, it had to be something like that, maybe a bolt or something? But, it really seemed like a rock. And there was no jet in the air.

For many years, that was what was in my head: something from a plane hit the middle of the street. Probably could've killed me.

It wasn't until well into my 30s that I read some kind of meteorite story about how they break up and could be quite small. I'm kind of a space geek but for whatever reason it had never occurred to me this idea of a meteorite being maybe even the size of your fist or smaller.

So now, I'm fairly convinced that it was a meteor and I was lucky it didn't kill me. I'm just kicking myself that I was too freaked out in the moment to go investigate the rock or object and bring it home.
posted by amanda at 8:48 PM on April 3 [4 favorites]


I thought at first the video might be like that viral GoPro thing from a while back.
posted by Kiwi at 11:36 PM on April 3


Look, I appreciate the endearing childlike naiveity of some mefites, but how many of these youtube hoaxes do we have to go through before people develop a little bit of logical skepticism.
I, on the other hand, do not appreciate your crass condescension.

How many youtube hoaxes involve national government funded media and museums?
posted by brokkr at 12:57 AM on April 4 [3 favorites]


Hans Amundsen is a real geologist who is staking his reputation on this. If its a hoax, it has gone too far.

I second the skepticism about probability calculations. You can get to any level of specificity in your calculations. There was no prerequisite that this be seen by a skydiver vs. say a glider or any number of things. It is a bit like throwing in the fact that it was seen by a Norwegian called Helstrup: What are the chances a meteor would be filmed by a Norwegian skydiver named Helstrup? So small, it won't be seen in this Universe.
posted by vacapinta at 1:13 AM on April 4 [1 favorite]


From your link, the Pontllyfni meteorite, significantly smaller than the purported meteorite in Norway, was observed as a fireball clearly visible in the noon time sky. The sonic boom caused the villagers to rush out into the streets. Just like the one in Alabama described above.

Objects of this size don't just sneak in. They are big, bright, loud events that are observable over wide areas.


From the link:

"This implied that the meteorite that fell at Coch-y-Bug near Pontllyfni was only a small fragment that broke off the main body as it passed through the Earth's atmosphere: most of the mass fell into the sea. This explained why John Lloyd Jones heard the rumbling sounds before the fall of the stone on the farm"

That is, the small 5 oz. meteorite that was recovered is assumed not to have created the brilliant fireball or loud noises.

From the American Meteor Society FAQ:
3. Can you see fireballs in daylight, and will a fireball leave a trail?

Yes, but the meteor must be brighter than about magnitude -6 to be noticed in a portion of the sky away from the sun, and must be even brighter when it occurs closer to the sun."

6. Can a fireball create a sound?

If a very bright fireball, usually greater than magnitude -8, penetrates to the stratosphere, below an altitude of about 50 km (30 miles), and explodes as a bolide, there is a chance that sonic booms may be heard on the ground below. This is more likely if the bolide occurs at an altitude angle of about 45 degrees or so for the observer, and is less likely if the bolide occurs overhead (although still possible) or near the horizon. "

7. How bright does a meteor have to be before there is a chance of it reaching the ground as a meteorite?

Generally speaking, a fireball must be greater than about magnitude -8 to -10 in order to potentially produce a meteorite fall.
Sounds like you could have a magnitude -8 to -10 meteor that
  1. Survives re-entry and hits the ground.
  2. Does not create a sonic boom heard on the ground.
  3. Is not bright enough to be seen at all, or is not so bright that it attracts any attention. Note that Iridium satellite flares are magnitude -9 and can be seen during daylight, sometimes, but are also easy to miss (video of a daylight Iridium flare).
(My childlike naivety comes with reading comprehension and scientific literacy!)

It's unlikely for sure, though someone has been hit by a meteorite and that's way less likely than seeing one pass close by, no matter what activity you're engaged in at the time. But without physical evidence (a recovered meteorite) it's a hard sell.
posted by jjwiseman at 1:24 AM on April 4 [2 favorites]


One would hope that not only are meteorite specialists involved, but also video manipulation experts.

(They might be able to tell by the pixels)
posted by panaceanot at 2:00 AM on April 4


Let's take the Occam's razor approach. The number of things that must be assumed to have happened for this to occur:

Hoax scenario:
-A second plane flying over head, dropping a rock which happens to fly by at just the right distance (Or a computer generated rock)
-A state TV channel producing the hoax, putting their reputation on the line
-Known experts and institutions playing along

Not a hoax:
-Gravity
posted by Snjo at 2:32 AM on April 4 [3 favorites]


Not a hoax:
-Gravity


Pfft. That's just a theory.
posted by jklaiho at 4:22 AM on April 4 [1 favorite]


"Enthusiastic Norwegian lady" is Eldrid Borgan (Google Translate's attempt here). She's got PhDs in chemistry and biotechnology, and is the current host of NRK's science show Shcrødingers katt. And she's pretty cool.
posted by Harald74 at 6:26 AM on April 4 [6 favorites]


So I just read someone on Twitter asserting that something on the order of 1900 meteors of 100 grams or larger hit the Earth every day. The one in the video is quite a bit bigger than that, but I'm not certain that the odds against this kind of occurrence are as high as the numbers that have been tossed around in this thread.

I hope it's not a hoax just because it's such a great story, equal parts goofy and scary. And I like the apparently picnic-like atmosphere of the meteorite hunting expedition. The whole thing plays like one of Gene Wolfe's lighter short stories.
posted by Ipsifendus at 8:09 AM on April 4


Statistically, it's probably more likely that the skydiver's buddy tried to murder him by dropping a rock on him. But I hope it's real because I'm fascinated with verifiable cases of physical and near-physical interactions between meteorites and people, animals, and things that people have constructed (February 15, 2013 really upped the ante there).
posted by jjwiseman at 8:23 AM on April 4


BTW, this clip has what purports to be several frames of video showing the Chelyabinsk meteorite, or a piece of it, in dark flight, just a rock falling out of the sky: https://www.youtube.com/watch?v=YgZuqm7893A#t=10m26s
posted by jjwiseman at 8:26 AM on April 4


I haven't looked into this at all, and my default position is one of skepticism, but it's worth noting that yes, there are a lot of objects hitting the Earth that are in roughly this mass range. Brown et al. (2002, Nature 420, 294) quote around 3000 10-kg impacts per year, and the numbers go way up for stuff smaller than that (~100,000 at 100 grams, 10 million at 1 gram). IIRC a 1-gram meteoroid can give you a bright visible meteor, but typically no meteorite; 100 gram or 10-kg objects will give you a fireball and maybe (on the largest end of that mass range only) meteorites.
posted by chalkbored at 9:25 AM on April 4


Oh, I think skepticism is warranted, but the whole "clearly it is a hoax because numbers!" and "you all are fooooools" crap is annoying.
posted by tavella at 10:51 AM on April 4 [6 favorites]


Phil Plait, Slate's "Bad Astronomy" blogger: "Does this footage actually show a meteorite? I can't be sure, but I lean that way."
posted by jjwiseman at 8:20 AM on April 5


A couple interesting things from a blog comment supposedly posted by Hans Amundsen, the geologist quoted in the FPP:
Some meteorites are rounded and totally covered by fusion crust (acquired at hypervelocities). Others go through svereal fragmentation events and show a mix of fusioned and freshly fractured surfaces. The fracture surface of an ordinary Chondrite has a color (and albedo) similar to concrete.

All the above does not prove that the rock passing the skydiver is a meteorite. But there is nothing in the observations (apparent velocity, shape, color, size) that precludes the hypothesis.

[...]

Most meteorites (meteors) are visible as high altitude fireballs and some explode with a "boom". Hollywood will happily make this happen at low altitude close to Bruce Willis ;). But these are the ones we notice. There are lots of cases where freshly fallen meteorites are found with no witness accounts of fireballs and booms. A fairly large space rock disintegrated over Oslo in March 2012. Nobody saw or heard anything. Apart from a couple of houseowners finding meteorites tucked in holes in their roof.

There are no reported firballs or sonic booms reported in connection with the skydiver incidence. Seismic stations operated by NORSAR were unfortunately down for maintenance. But more importantly - the area is home to one of the largest army test ranges in Norway. Local people stopped noticing booms long ago...
And an important question, right up metafilter's alley, from twitter: "If a skydiver snatches a meteoroid out of the sky does it become a meteorite at once or on landing?"
posted by jjwiseman at 11:46 AM on April 5 [2 favorites]


"If a skydiver snatches a meteoroid out of the sky does it become a meteorite at once or on landing?"

Originally, the meteoroid/meteorite distinction held that the meteoroid was the object as it moved through space (thus cognate with "asteroid"); once it enters earth's atmosphere it is no longer a "meteoroid" but a "meteor." Once the skydiver catches it it is hard to think of it as a "meteor" so I think "meteorite" is probably the best word.

On the other hand, these are largely distinctions that exist for the sheer joy of sneeringly correcting someone. We don't use a different term for a space shuttle when it's in space, when it's entering the atmosphere and when it lands on the ground--we really don't need three separate terms for a chunk of space-rock in those three states either.
posted by yoink at 3:19 PM on April 5 [1 favorite]


Actually the "Shuttle" refers to the whole assembly - the orbiter, the solid rocket boosters, and the external tank. Once the orbiter vehicle has lost those components it's not the shuttle anymore. So in a way we do have different terms.

/sneer
posted by Big_B at 5:00 PM on April 5


Follow-Up: The Meteorite and the Skydiver
posted by homunculus at 8:10 PM on April 7


Bad Astronomy: (Final) Followup: Yup. It Was a Rock.. More from Norway. "The bad news: There is no meteorite. It was a rock accidentally packed into the parachute."
posted by Nelson at 11:46 AM on April 8 [1 favorite]


Hah. Called it.
posted by fimbulvetr at 12:58 PM on April 8 [1 favorite]


Who packs a rock in a parachute?
posted by postcommunism at 1:53 PM on April 8


Well, it wasn't so much a rock as a pebble:

"A pebble, a few cm in size at most, was accidentally caught inside the parachute at the landing site after the previous jump."

So that explains how it got in there. Even with all their calculations, it was apparently hard to judge the scale of the thing. And the smaller and closer the object, the slower it had to fall to maintain the same visual speed.
posted by Snjo at 2:05 AM on April 9


Can someone explain how they arrived at the conclusion, in the end? It is not clear from the articles linked.

The Bad Astronomy guy seems to base it on a second rock, except he then recants and points out the second rock is actually another skydiver.
posted by vacapinta at 2:21 AM on April 9


So neither a hoax or a meteorite. Sounds about right.
posted by tavella at 6:37 AM on April 9


Can someone explain how they arrived at the conclusion, in the end? It is not clear from the articles linked.

Yeah, from what I can tell no additional evidence has come to light and there has been no breakthrough in video analysis, so I'm not sure why the new conclusion is presented so confidently.
posted by jjwiseman at 8:59 AM on April 9


Followup analysis confirms it was a piece of gravel likely in the chute that opened, Apollo 12 data used.
posted by Brian B. at 1:42 PM on April 26 [3 favorites]


Wow, the followup analysis is so cool.
posted by heyho at 12:18 PM on April 30


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