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Asteroids, meteors, and meteorites
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| midtskogen | Date: Sunday, 20.04.2014, 09:24 | Message # 166 |
 Star Engineer
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Norway
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| Yes, we exchanged a couple e-mails since he mentioned my article anyway. I assured him that the videos are real and that the publication really is a crowdsourcing effort. I also mentioned that I believed that the discussion would mainly boil down to whether something was accidentally packed in the parachute or it was a meteorite, and he seemed to shift from originally dismissing the pebble in the parachute idea to favour it. 
I, and nobody else who'd looked at this, had no idea how a pebble could teleport from the parachute to a place high above well after it was fully deployed, and even meteorites seem more plausible than teleportation. But if someone was able to explain everything, it was feeling that it would explain the teleportation.
Here's an update.
The details are unclear, but as I wrote, it doesn't really matter now. Crowdsourcing is interesting.
ADDENDUM: Plait the Bad Astronomer will post a follow-up shortly.
And here it is. He mistakes the second diver for debris, though, as many others have (not HarbingerDawn).
What's left for us to do is to make a plaque for ground zero: "On 17th June 2012 a small pebble fell here viewed by 6 millions on YouTube".Added (12.04.2014, 20:17)
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Update on Universe Today.
I just realised: We were closer to the answer than we knew when we did the calculations. Ironically, "calculus" is Latin for "pebble"... Added (20.04.2014, 12:24)
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Large fireball, probably near the border between Russia and Finland:
http://norskmeteornettverk.no/wordpress/?p=1515
NIL DIFFICILE VOLENTI
Edited by midtskogen - Tuesday, 08.04.2014, 20:31 |
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| Destructor1701 | Date: Sunday, 20.04.2014, 21:01 | Message # 167 |
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Pioneer
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Ireland
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| Cool footage.
Russia must be feeling a little queasy.
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| midtskogen | Date: Monday, 21.04.2014, 13:37 | Message # 168 |
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Star Engineer
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Norway
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| I'm not sure if this one went down in Russia, Finland or Norway. My gut feeling so far based on eyewitness reports is in Russia, not far east or southeast of the point where Norway, Finland and Russia meet. But I haven't got positions and bearings for the videos, which will offer much better accuracy. There are several reports of thundering or crackling sounds, and the event seems to have been recorded by several Norwegian seismic stations, all a very good sign for meteorites.
It wont be an easy area to seach for meteorites. It's is for the most part soft ground dominated by birch forest. But if fragments landed on a lake or open areas perhaps there is a window of a few weeks ahead with a slight chance of finding holes in the snow.Added (21.04.2014, 16:37)
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A Finnish preliminary analysis puts it in Russia, a few km from the Norwegian border: http://www.avaruus.fi/uutiset....la.html
It's seems very likely that meteorites were dropped.
NIL DIFFICILE VOLENTI
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| Chris94 | Date: Monday, 21.04.2014, 16:05 | Message # 169 |
 Space Pilot
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| I heard that the fireball flew across Northern Norway and crashlanded somehwere in Murmansk in Russia.
Too bad i didn't saw this one, it is very cloudy here in Bodø i live.
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| midtskogen | Date: Monday, 21.04.2014, 19:01 | Message # 170 |
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Star Engineer
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| How Apollo 12 Helped Solve the Skydiver Meteorite Mystery. It's actually pretty cool how this story turned out after we went public.
NIL DIFFICILE VOLENTI
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| HarbingerDawn | Date: Tuesday, 06.05.2014, 00:26 | Message # 171 |
 Cosmic Curator
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| Wonderful daylight bolide near Toronto
All forum users, please read this!
My SE mods and addons
Phenom II X6 1090T 3.2 GHz, 16 GB DDR3 RAM, GTX 970 3584 MB VRAM
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| Betelgeuze | Date: Saturday, 17.05.2014, 18:44 | Message # 172 |
 Space Pilot
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Belgium
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| in 2035 or 2029 not all asteroids only Apophis asteroid hitting earth
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| DoctorOfSpace | Date: Saturday, 17.05.2014, 18:54 | Message # 173 |
 Galaxy Architect
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Pirate
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| Quote Betelgeuze (  ) only Apophis asteroid hitting earth
It isn't going to hit the Earth.
Intel Core i7-5820K 4.2GHz 6-Core Processor
G.Skill Ripjaws V Series 32GB (4 x 8GB) DDR4-2400 Memory
EVGA GTX 980 Ti SC 6GB
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| midtskogen | Date: Tuesday, 01.07.2014, 12:27 | Message # 174 |
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Star Engineer
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| Meteorites from the big bolide over the Kola peninsula 2014-04-18 have been found!
It was observed from Russia, Norway and Finland. Shortly after the incident I teamed up with the Finnish fireball group and by analysing the available information we found a likely debris field. An expedition was organised which recovered two fragments within the predicted debris field and with sizes expected in that part of the debris field!
Ursa press release
Ural Federal University news
Ditto (Russian)
Norwegian Meteor Network (Norwegian)
Tähdet ja avaruus (Finnish)
Universe Today
The meteorites have been classified as H5 chondrites.
EDIT: updated links.
NIL DIFFICILE VOLENTI
Edited by midtskogen - Tuesday, 01.07.2014, 22:00 |
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| spacer | Date: Tuesday, 12.08.2014, 01:24 | Message # 175 |
 Star Engineer
Group: Users
Israel
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| tonight i saw here 2-3 meteorites with full moon and lot of light from Nearby towns and houses
tomorrow will be more! 3:22 am now here so if you say that you will not see because the moon (i heard that from lot of people)
just get outside and look up! if i can to see with all the light and the moon! you will be also able too! 
"we began as wanderers, and we are wanderers still"
-carl sagan
-space engine photographer
Edited by spacer - Tuesday, 12.08.2014, 01:25 |
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| midtskogen | Date: Thursday, 14.08.2014, 18:04 | Message # 176 |
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Star Engineer
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| Looking at the latest Rosetta image I wonder how gravity will make anything settle that is dropped on the comet. For instance, those cliffs in the middle part are pretty deep. Let's say you kick up some dust at the bottom. Would it eventually settle at the bottom again, or would the dust rather prefer to fall to the cliffs?
NIL DIFFICILE VOLENTI
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| Watsisname | Date: Friday, 15.08.2014, 01:51 | Message # 177 |
 Galaxy Architect
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| This comes down to determining geodesics around non spherically-symmetric and rotating mass distributions, which can get pretty complicated in a hurry. Basic idea is it will prefer to fall somewhat towards one of the cliffs. But there are a lot of effects that factor in enormously here.
First off, let's suppose you have a deep canyon on a non-rotating and otherwise spherically symmetric object, and the volume of the canyon is small relative to the total volume. In this case the particles will not be attracted to the walls by gravity. They'll fall straight to the bottom. This might sound counter-intuitive, but it's a similar idea as having a particle within a hollow sphere (and not at the exact center). It won't be drawn to the nearest point on the shell because the field within the hollow is everywhere zero.
Now let's say the volume of the canyon is significant relative to the size of the body. Basically imagine a pac-man shape, to the extreme case of a half-sphere. Then the center of mass is offset away from the canyon and particles will tend to slide over to the nearest wall. Not because that wall is attracting them, but because the path to the CoM intersects it.
Then there is the effect of rotation. If the rotation rate is appreciable relative to the surface gravity, then the coriolis force will deflect their paths. 67P/Churyumov–Gerasimenko (which I'll now just call Kevin) has a rotation rate of ~12 hours and a very weak gravitational field, so coriolis forces is going to be very important indeed.
Next and most obvious, if the body's shape departs appreciably from spherical symmetry such that there is much more mass towards one side of the canyon than another, then dust will be preferentially drawn to that side. Kevin has two "lobes", one of which is much more massive than the other, so the center of mass is strongly offset towards it.
Finally there's the non-gravitational effect of solar radiation pressure which will be important for small dust grains.
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| midtskogen | Date: Monday, 08.09.2014, 08:29 | Message # 178 |
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Star Engineer
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Norway
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| Caught a nice, fast fireball last night:
http://norskmeteornettverk.no/bilder/2014/meteor-20140815.jpg
Videos: high resolution, low resolution
Added (08.09.2014, 07:29)
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Meteorite creates 12 meter wide crater in Nicaragua, government reports.
While plausible to some extent, I'd like to wait a bit longer for more information before concluding. This coincided with the "near" miss of asteroid 2014 RC, which missed Earth by 40,000 km, and this is cited as evidence for it being a meteorite. I'd rather count the coincidence as an argument against rather than for, since the coincidence and the visibility of the miss in the news could have caused the authorities to jump to the conclusion before investigating other possible causes for an explostion.
NIL DIFFICILE VOLENTI
Edited by midtskogen - Monday, 08.09.2014, 08:30 |
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| Betelgeuze | Date: Monday, 08.09.2014, 13:28 | Message # 179 |
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Space Pilot
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Belgium
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| I live in belgium in the night/evening there a meteor it's only 1 meteor not much too i'm still alive
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| midtskogen | Date: Wednesday, 19.11.2014, 07:30 | Message # 180 |
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Star Engineer
Group: Users
Norway
Messages: 1674
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| Another big Russian bolide caught on dashcam:
There's some confusion in the press whether this is a meteor or something else. There can surely be several explanations, but it surely looks like a big bolide behind the clouds, so unless contrary evidence surfaces (such as nothing to be seen some km away despite clear conditions), I'm assuming that this is a bolide. A lack of a sonic shock wave like in Chelyabinsk does not necessarily conflict with a meteor.
UPDATE:
Two more videos:
The second video strongly indicates that it was something else (explosive fire perhaps?), since the kids had time to start filming before the main event.
NIL DIFFICILE VOLENTI
Edited by midtskogen - Wednesday, 19.11.2014, 17:32 |
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