|
Robotbeat
|
|
« Reply #135 on: 02/15/2013 08:10 PM » |
|
It's a good thing in my opinion.
Oh, I agree there, but talk is cheap.
What are you doing about it?
|
|
|
|
|
|
ugordan
|
|
« Reply #137 on: 02/15/2013 08:15 PM » |
|
Found a video with a full length meteor going through atmosphere to shockwave impact.
Meteorite passes by at 4:40 in video.
Shockwave impact at 7:01 in video.
Thats a dramatic 2m21s in time delay, or 48km away assuming speed of sound at sea level.
The angle is also oblique as well, but we should be able to guesstimate the altitude from that.
<![CDATA[<a href="http://www.youtube.com/v/gQ6Pa5Pv_io&rel=1" target="_blank">http://www.youtube.com/v/gQ6Pa5Pv_io&rel=1</a>]]>
Wow, thanks for the find! Watching this, I'll have to revise my energy estimate. Producing that amount of bang and window movement at that distance, this couldn't have been produced by a low kiloton equivalent. Dare I say around 1 megaton event? Edit: note that this is also probably the first video that shows 2 or 3 distinct fragments after the bright breakup.
|
|
|
|
notsorandom
|
|
« Reply #138 on: 02/15/2013 08:16 PM » |
|
Let the hearings begin!
http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth
It does make NASA less of a target for cuts (from just a social/political perspective).
This is a legitimate threat to humanity and our nation. As real as North Korea or Iran.
Sometimes I really have to wonder about space advocates who talk about how the public doesn't care and either how that's unfair/stupid or how it's inevitable. And when space DOES enter the public's eye, they brush it off, poo-poo it, and usually don't take the opportunity to educate people.
It doesn't surprise me all that much that threats from NEOs are not talked about that much by space advocates. There is little to no relationship between asteroid threats and the various issues people tent to be passionate about (human spaceflight, Mars, etc.).
|
|
|
|
ugordan
|
|
« Reply #139 on: 02/15/2013 08:17 PM » |
|
What are you doing about it?
Nothing. Not a U.S. taxpayer so my opinion is inconsequential for all practical purposes.
|
|
|
|
mmeijeri
|
|
« Reply #140 on: 02/15/2013 08:18 PM » |
|
With that second image, I'm satisfied they're unrelated.
Hmm, exquisite timing then.
|
|
|
|
Lar
|
|
« Reply #141 on: 02/15/2013 08:20 PM » |
|
It doesn't surprise me all that much that threats from NEOs are not talked about that much by space advocates. There is little to no relationship between asteroid threats and the various issues people tent to be passionate about (human spaceflight, Mars, etc.).
Really doing a good job of defense requires a LOT of eyes watching (to find) and pretty serious space based infrastructure (to remediate). We spacers should be riding this pony because space based infrastructure/manufacturing is the key to everything else. IMHO anyway
|
|
|
|
Star One
|
|
« Reply #142 on: 02/15/2013 08:21 PM » |
|
With that second image, I'm satisfied they're unrelated.
Hmm, exquisite timing then.
Useful timing as far as getting the issue up the agenda.
|
|
|
|
R7
|
|
« Reply #143 on: 02/15/2013 08:23 PM » |
|
Dare I say around 1 megaton event?
Unlikely. Estimates have been ~10 tonnes and 20km/s, that gives 'just' 2TJ, little shy of half kiloton worth of KE.
|
|
|
|
smoliarm
|
|
« Reply #144 on: 02/15/2013 08:24 PM » |
|
Found a video with a full length meteor going through atmosphere to shockwave impact.
Meteorite passes by at 4:40 in video.
Shockwave impact at 7:01 in video.
Thats a dramatic 2m21s in time delay, or 48km away assuming speed of sound at sea level.
The angle is also oblique as well, but we should be able to guesstimate the altitude from that.
One more full video of event allowing more accurate estimate, since the location is known:
<![CDATA[<a href="http://www.youtube.com/v/efvP-RRuJuA&rel=1" target="_blank">http://www.youtube.com/v/efvP-RRuJuA&rel=1</a>]]>Local time is in the low-right corner The camera is in the northern outskirt of the city, no more than 10 km from epicenter. First flash = 9:20:03 Second flash = 9:20:05 (major) Shock wave = 9:22:22 Delay = 137 sec. Now, on speed of sound - it was minus 13 C, altitude ~ 205 m. I did simple graph approximation for [0.25 -- 40 km] and got average 305 m/sec. This gives distance of 41.8 km. Assuming the range to epicenter as 10 km, the altitude of explosion was 40.6 km Given the range of 10 km is a max estimate, I'd give the final number as 41 +/- 0.5 km
|
|
|
|
jcm
|
|
« Reply #145 on: 02/15/2013 08:28 PM » |
|
Dare I say around 1 megaton event?
Unlikely. Estimates have been ~10 tonnes and 20km/s, that gives 'just' 2TJ, little shy of half kiloton worth of KE.
New estimates based on infrasound stations (and I don't know how they derive the result) claim 15m dia, 7000 tonnes, and hundreds of kT
|
|
|
|
|
|
jcm
|
|
« Reply #147 on: 02/15/2013 08:29 PM » |
|
I agree with Jorge's latest that it seems unrelated - unless maybe it aerobraked in the southern hemisphere unseen and ended up making half an orbit, like an Apollo/Zond skip reentry
|
|
|
|
R7
|
|
« Reply #148 on: 02/15/2013 08:33 PM » |
|
No way was this amount of bang produced by 0.5 KT. NASA are now estimating the diameter at 15 m and mass at about 7000 tons.
I did wonder that 0.5kt sound low. But 7000 tons .. wow!edit: about the mlinder second image, isn't it weird that the approximated meteor trajectory is almost straight from the sun? Things flying such orbit should have had insane velocity, no? Or maybe I just read it incorrectly.
|
|
|
|
mmeijeri
|
|
« Reply #149 on: 02/15/2013 08:35 PM » |
|
Any idea on whether the alleged event in Cuba is real? Amusingly, there could still be a link between the Cuban event, if it happened, and either the big asteroid or the Russian meteor, but not both, now that we know that the latter two are unrelated. Or the Cuban event could be a false report, which is what I’m inclined to believe.
|
|
|
|
