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General Astronomy >> General Observing and Astronomy

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Littlegreenman
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Meteorite hits Russia, people injured
      #5680591 - 02/15/13 02:32 AM

This just in on the 11 PM Pacific Time news: A meteorite appears to break up at 30,000 feet over Russia, about 1,000 miles east of Moscow. At least 100 injuries reported mostly due to broken glass from shock waves? Sonic booms? Video showing from several angles is showing up. Some objects appear to have hit ground. News outlets don't know the difference between a meteor, meteorite, and a meteor shower, but we knew that.

As more facts come in some of the above may be corrected.
LGM


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core
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Re: Meteorite hits Russia, people injured new [Re: Littlegreenman]
      #5680601 - 02/15/13 02:38 AM

fwiw NEO and Space Rocks sub forums have youtube links to various footage ...

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Gus1974
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Re: Meteorite hits Russia, people injured new [Re: core]
      #5680636 - 02/15/13 03:23 AM

Scary stuff.

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Astrojensen
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Re: Meteorite hits Russia, people injured new [Re: Gus1974]
      #5680657 - 02/15/13 03:51 AM

http://rt.com/news/meteorite-crash-urals-chelyabinsk-283/

Some reports indicate that the incoming meteorite was intercepted by a quick-response (automatic?) surface to air missile. This needs verification.

In any way: It has happened. A meteorite airburst has hit a populated area. This will hopefully wake some people up. It seems it was extremely close to a regional disaster. If it had happened over Moscow, then imagine the chaos...


Clear skies!
Thomas, Denmark


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Dave Mitsky
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Re: Meteorite hits Russia, people injured new [Re: Astrojensen]
      #5680678 - 02/15/13 04:44 AM

Here are links to two more articles on the event:

http://www.space.com/19801-possible-meteor-blast-russia.html

http://news.discovery.com/space/asteroids-meteors-meteorites/huge-fireball-ex...

Dave Mitsky


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Dave Mitsky
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Re: Meteorite hits Russia, people injured new [Re: Dave Mitsky]
      #5680690 - 02/15/13 05:25 AM

Phil Plait's article can be seen at http://www.slate.com/blogs/bad_astronomy/2013/02/15/breaking_huge_meteor_expl...

Dave Mitsky


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Astrojensen
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Re: Meteorite hits Russia, people injured new [Re: Dave Mitsky]
      #5680699 - 02/15/13 05:42 AM

In this video:

http://www.youtube.com/watch?v=4ZxXYscmgRg

It seems like the meteor actually just bounces off the atmosphere and zips out in space again (you can see it briefly at the end of the trail as a white spot that moves away from the trail rapidly and disappears).

If so, then it wasn't an airburst explosion, but just a sonic boom and a drizzle of small fragments from a MUCH larger body. Seems that a lot of people just had a very, very lucky day. And I'm not talking about getting a famous video on YouTube, but to be alive at all...

Ouch. Seems this one was a little too close for comfort.


Clear skies!
Thomas, Denmark


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demiles
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Re: Meteorite hits Russia, people injured new [Re: Astrojensen]
      #5680701 - 02/15/13 05:45 AM

Just watched some of the video, amazing!

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Andy Howie
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Re: Meteorite hits Russia, people injured new [Re: demiles]
      #5680709 - 02/15/13 05:57 AM

20ft crater found.

84 children injured. 112 people hospitalised. Injury count at 550.

Sonic boom captured on vid.........

http://www.liveleak.com/view?i=b70_1360910617

-14C and no windows is a bad combination

Best wishes to those folk out there.


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Astrojensen
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Re: Meteorite hits Russia, people injured new [Re: Andy Howie]
      #5680716 - 02/15/13 06:12 AM

Another video which seems to support that the meteor just grazed the atmosphere and went out back in space again: (around 0:52, lefthand screen)

http://www.youtube.com/watch?v=f525TmMSBs0


Clear skies!
Thomas, Denmark


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Qwickdraw
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Re: Meteorite hits Russia, people injured new [Re: Astrojensen]
      #5680737 - 02/15/13 06:37 AM

Quote:

InIt seems like the meteor actually just bounces off the atmosphere and zips out in space again (you can see it briefly at the end of the trail as a white spot that moves away from the trail rapidly and disappears).

Clear skies!
Thomas, Denmark




I am going to guess that what remained did not "zip" back into space but landed dozens of miles away. I believe its velocity was severely lowered during the burst and its altitude was then too low to escape Earth's gravity at that point.


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leviathan
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Re: Meteorite hits Russia, people injured new [Re: Qwickdraw]
      #5680752 - 02/15/13 07:04 AM

The most up-to-date videos and photos are on this topic:

http://www.astronomy.ru/forum/index.php/topic,104303.0.html

Thomas, idea of bouncing the atmosphere was also discussed there. But now they say that they've found 6m hole on frozen surface of lake near the city.


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leviathan
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Re: Meteorite hits Russia, people injured new [Re: leviathan]
      #5680758 - 02/15/13 07:09 AM

On these videos you can watch the effect of shock wave:

http://www.youtube.com/watch?feature=player_embedded&v=_nOaRpF0DJk

http://www.youtube.com/watch?feature=player_embedded&v=efvP-RRuJuA

http://www.youtube.com/watch?feature=player_embedded&v=qch-pIEgf44#at=10


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swalker
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Re: Meteorite hits Russia, people injured new [Re: leviathan]
      #5680783 - 02/15/13 07:37 AM

That's not a meteor crater, that's a burning sinkhole leaking natural gas or methane. A meteor isn't going to leave a burning hole.
Highly doubtful this rock bounced back into space. Intriguing!


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BrooksObs
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Re: Meteorite hits Russia, people injured new [Re: swalker]
      #5680887 - 02/15/13 08:57 AM

There is nothing in the images posted so far on the Internet to suggest that the reported damage is from an "airburst" event. Actual structural damage, except to one zinc factory is not evident beyond broken windows. Rather, it looks like the damage was generated by a relatively low altitude, very strong, sonic boom. Likewise, the meteor does not terminate in a sudden flash but rather continues onward after a sharp peak in brightness (a point at which the double smoke trail suggests it broke into two major fagments?) for some distance before slowly fading out. Nor is there anything to imply the strike was a grazing event, since all the video so far shows an angle of descent in the track, not near earth paralleling flight.

BrooksObs

Edited by BrooksObs (02/15/13 08:59 AM)


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Achernar
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Re: Meteorite hits Russia, people injured new [Re: Astrojensen]
      #5680946 - 02/15/13 09:21 AM

Very unlikely, not with the kind of velocity it came in with. Nuclear missiles don't fly anywhere near that fast, let alone surface to air missiles. Even if one did take off because someone thought a nuclear attack was in progress, it couldn't have intercepted it. Moreover, knowing how many asteroids are loose piles of boulders, gravel and dust, I wouldn't be quick to dismiss any possibility that this event was related to the asteroid flyby. As we have seen back in 1994, a planet can pull a loosely held together object apart, turning it into a shotgun blast of impactors. There is no reason to dismiss out of hand that a similar occurance here on Earth can take place. This was a very close call, this object or objecs nearly took out a city. That can spell really big trouble, if it was mistaken for a nuclear attack.

Taras


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Ravenous
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Re: Meteorite hits Russia, people injured new [Re: Achernar]
      #5680960 - 02/15/13 09:27 AM

Quote:

I wouldn't be quick to dismiss any possibility that this event was related to the asteroid flyby.



This is a great idea, but sadly I think not likely - DA14 is approaching from the southern hemisphere and this struck fairly high in the North.

However it's an amazing coincidence, two in a day from completely dfferent directions. Prepare for a lot of uninformed media chatter about cosmic conspiracies against us...


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Tom Polakis
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Re: Meteorite hits Russia, people injured new [Re: Littlegreenman]
      #5680966 - 02/15/13 09:28 AM

What strikes me from the video from the moving car is that it takes 10 seconds from the time it becomes visible until impact. The longest duration of a meteor (not space junk) that I have ever seen has been several seconds. Is the meteoroid decelerated that much by the earth's atmosphere, or was this one on a trajectory that nearly matched the earth's orbital velocity?

Tom


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bunyon
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Re: Meteorite hits Russia, people injured new [Re: Tom Polakis]
      #5680979 - 02/15/13 09:33 AM

Tom, another explanation is that it got much lower (closer to observer) than most. Most meteors stay very high and, therefore, go through less atmosphere and are visible for shorter lengths of time.

At least, that is one non-experts interpretation, because I had the same thought you did.


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CharlesW
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Re: Meteorite hits Russia, people injured new [Re: bunyon]
      #5681022 - 02/15/13 09:54 AM

USA Today's video. http://usat.ly/14WfaIa

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Tom Polakis
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Re: Meteorite hits Russia, people injured new [Re: bunyon]
      #5681023 - 02/15/13 09:54 AM

Quote:

Tom, another explanation is that it got much lower (closer to observer) than most. Most meteors stay very high and, therefore, go through less atmosphere and are visible for shorter lengths of time.




Paul,

Yeah, that's probably all it is. Now I just thought about that classic video of the grazer over the Grand Tetons from the 70's, and it moved at an equally "slow" rate. It's probably moving at thousands of miles per hour, but far away.

Tom


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Dave Mitsky
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Re: Meteorite hits Russia, people injured new [Re: CharlesW]
      #5681486 - 02/15/13 01:23 PM

The number of people injured now stands at more than 1,000.

The airburst is estimated to have occurred at 10,000 meters and the mass of the bolide at 10 tons. I've seen speeds ranging from 33,000 to 67,000 miles per hour mentioned.

Apparently, three craters have been found.

Dave Mitsky


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Mark9473
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Re: Meteorite hits Russia, people injured new [Re: Astrojensen]
      #5681515 - 02/15/13 01:32 PM

Quote:

Another video which seems to support that the meteor just grazed the atmosphere and went out back in space again



Thomas, what you're seeing is the meteoroid decelerating to the point that it no longer ionizes the air it passes through.


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csrlice12
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Re: Meteorite hits Russia, people injured new [Re: Mark9473]
      #5681526 - 02/15/13 01:36 PM

Wasn't there an asteroid or something that was supposed to travel between the Earth and the Moon recently?? Could this be that or a part of it?

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BrooksObs
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Re: Meteorite hits Russia, people injured new [Re: csrlice12]
      #5681548 - 02/15/13 01:45 PM

Csrlice - There is currently the asteroid 2012DA14 about to approach very close to earth, however the approach direction is almost directly from the south celestial pole, with the "radiant" of any associated pieces blocked as seen from earth's northern hemisphere where the meteor itself was seen from. Thus, the Russian event is simply a coincidence.

BrooksObs

Edited by BrooksObs (02/15/13 01:57 PM)


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Mark9473
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Re: Meteorite hits Russia, people injured new [Re: csrlice12]
      #5681549 - 02/15/13 01:46 PM

No, this meteorite event in Russia is from a stone that traveled north-to-south; the asteroid 2012 DA14 (that you can now follow live at http://www.ustream.tv/nasajpl2 ) is going south-to-north.

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careysub
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Re: Meteorite hits Russia, people injured new [Re: Astrojensen]
      #5681620 - 02/15/13 02:13 PM

Quote:

http://rt.com/news/meteorite-crash-urals-chelyabinsk-283/

Some reports indicate that the incoming meteorite was intercepted by a quick-response (automatic?) surface to air missile. This needs verification.




This story seems to have disappeared. Probably people misinterpreting the bolide trail.

Quote:

In any way: It has happened. A meteorite airburst has hit a populated area. This will hopefully wake some people up. It seems it was extremely close to a regional disaster. If it had happened over Moscow, then imagine the chaos...




Not just any populated area!

One of Russia's two nuclear weapons production cities (Chelyabinsk, that is, the other being Sarov). This must have been quite exciting for the Russian military.


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GlennLeDrew
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Re: Meteorite hits Russia, people injured new [Re: careysub]
      #5681722 - 02/15/13 02:56 PM

Do not base space motion *only* from trajectories as observed from a moving and rotating platform. The two principal components which have to be 'subtracted', as it were, are the Earth's own 29.7km/s motion and the location of the observer on the round Earth at the time of the event. The derived true space motion can differ quite substantially from the apparent motion.

In any event, I suspect this and DA14 to be unrelated. But we'll very soon know...


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careysub
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Re: Meteorite hits Russia, people injured new [Re: BrooksObs]
      #5681726 - 02/15/13 03:00 PM

ADDENDUM: Recent images of the damage show that blast pressures in the range of 2 psi were encountered - building walls show buckling. This is well outside of the pressure range any sonic boom can generate. This was an explosion.


Quote:

There is nothing in the images posted so far on the Internet to suggest that the reported damage is from an "airburst" event.




On the contrary - images and damage reports appear EXACTLY like an airburst event!

Quote:

Actual structural damage, except to one zinc factory is not evident beyond broken windows. Rather, it looks like the damage was generated by a relatively low altitude, very strong, sonic boom.




And this is exactly what a relatively high altitude explosion will do.

Windows break in the blast pressure regime of 0.5-1 psi with negligible other structural damage. A 1 kiloton explosion above a mere 1000 meters from the ground will not produce blast pressure much above 1 psi anywhere. For a 10 kiloton explosion this height is about 2.2 km.


Quote:

Likewise, the meteor does not terminate in a sudden flash but rather continues onward after a sharp peak in brightness (a point at which the double smoke trail suggests it broke into two major fagments?) for some distance before slowly fading out.




A meteor is not a bomb. There is no reason to expect it completely vanish when it explodes. In fact if it did that would be extremely surprising.

The explosion (when the body fragments and dumps most of its energy into the atmosphere very fast) should leave remnant large fragments that continue the trajectory.

Here is an excellent view of the explosion and termination.

http://www.youtube.com/watch?v=90Omh7_I8vI

Note that the remaining travelling remnant is small fraction of the brightness of the pre-explosion bolide. Also note the grossly swollen trail in the explosion region, where all the explosion debris is deposited.

The brilliant sudden flash is an explosion almost by definition.

Quote:

Nor is there anything to imply the strike was a grazing event, since all the video so far shows an angle of descent in the track, not near earth paralleling flight.




This is a non-sequitur.

Regardless on angle of entry (BTW, I measure about 15 degrees for this in multiple videos, a shallow entry angle) all moderately large meteors experience explosive fragmentation when the hit sufficiently dense air (except for the 1 in 1000 that is metallic and thus physically very strong).

There is no requirement that they have a negligible entry angle.

Edited by careysub (02/15/13 09:45 PM)


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Intensity2x
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Re: Meteorite hits Russia, people injured new [Re: careysub]
      #5681747 - 02/15/13 03:10 PM

Preliminary data from NASA JPL:
Quote:

Preliminary information indicates that a fireball in Chelyabinsk, Russia, is not related to asteroid 2012 DA14, which is flying by Earth safely today.

The Russian fireball is the largest reported since 1908, when a fireball hit Tunguska, Siberia. The fireball entered the atmosphere at about 40,000 mph (18 kilometers per second). The impact time was 7:20:26 p.m. PST, or 10:20:26 p.m. EST on Feb. 14 (3:20:26 UTC on Feb. 15), and the energy released by the impact was in the hundreds of kilotons.

Based on the duration of the event, it was a very shallow entry. It was larger than the fireball over Indonesia on Oct. 8, 2009. Measurements are still coming in, and a more precise measure of the energy may be available later. The size of the object before hitting the atmosphere was about 49 feet (15 meters) and had a mass of about 7,000 tons.

The fireball, which was about one-third the diameter of asteroid 2012 DA14, was brighter than the sun. Its trail was visible for about 30 seconds, so it was a grazing impact through the atmosphere.

It is important to note that this estimate is preliminary, and may be revised as more data is obtained.





Energy release of "several hundreds of kilotons", thats a big boom.

Source: http://www.jpl.nasa.gov/news/news.php?release=2013-061


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Astrojensen
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Re: Meteorite hits Russia, people injured new [Re: Mark9473]
      #5681810 - 02/15/13 03:41 PM

Quote:

Thomas, what you're seeing is the meteoroid decelerating to the point that it no longer ionizes the air it passes through.




I realized this later. Now they also report multiple impact sites, so it seems safe to say it didn't escape back into space.


Clear skies!
Thomas, Denmark


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MawkHawk
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Re: Meteorite hits Russia, people injured new [Re: Astrojensen]
      #5681836 - 02/15/13 03:54 PM

Pretty gosh darn amazing, is all I can say... Spectacular.

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Happy Birthday JayinUT
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Re: Meteorite hits Russia, people injured new [Re: MawkHawk]
      #5681864 - 02/15/13 04:09 PM

Biggest impact since Tunguska is a rather large event. Imagine if it had come down in a major urban center. On another avenue wish I could go meteorite hunting in Russia right now. I'd love to have a small fragment as seen in this Russian web site that shows a 30 foot impact hole on a reservoir with small fragments around the hole. The Russian link is in Russian which I translated in Google Chrome on my laptop. Nice that they put a ruler next to the fragments. One third of the size of the asteroid that flew by and we missed this one. I say we still need to fund finding this things as they fly in the inner solar system. We may not have an extinction level event but having one like this hit an urban area would not be good if you lived there or had family there.

Russian Link

Edit: On a side note this is probably the second largest impact since Tunguska if the NASA numbers hold. The third event is the Sikhote-Alin Meteorite that hit in eastern Siberia in 1947 in the then Soviet Union. That was a daytime event and like this one, the explosion was brighter than the Sun. Here is some info:

Link 1

Link 2

Edited by JayinUT (02/15/13 04:26 PM)


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Dave Mitsky
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Re: Meteorite hits Russia, people injured new [Re: JayinUT]
      #5681887 - 02/15/13 04:20 PM

There's more on the hole in the ice plus a video of the bolide from a weather satellite at http://www.slate.com/blogs/bad_astronomy/2013/02/15/russian_meteorite_fragmen...

Dave Mitsky


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WarmWeatherGuy
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Re: Meteorite hits Russia, people injured new [Re: JayinUT]
      #5681902 - 02/15/13 04:31 PM

I noticed on one of the videos that people are still confused about the shock waves. They are not created when an object goes through Mach 1. They are created while an object travels faster than Mach 1. The shock wave travels through the air at the same speed as the object. When the shock wave passes you then you will hear the sonic boom. If the object is traveling at Mach 1 the angle of the shock wave is 90 (perpendicular to the direction of travel). If a plane flies horizontally at Mach 1 you will hear the boom when it is overhead. As the Mach number increases the angle of the shock wave decreases. At Mach 2 the angle becomes 30 (60 from the perpendicular) and you will hear the boom after the plane has passed.

The angle of the shock wave is the arcsine of 1/M where M is the Mach number. So for Mach 1 the angle is 90, Mach 2 it is 30, Mach 3 it is 19.5.

This misconception was advertised on the news when a reporter heard the sonic boom from the space shuttle as it was coming in to land. The reporter claimed he heard the boom because the shuttle had just broken through the sound barrier. In reality he heard the boom because the shuttle flew by while traveling faster than Mach 1.


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northernontario
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Re: Meteorite hits Russia, people injured new [Re: Dave Mitsky]
      #5681914 - 02/15/13 04:36 PM

Wow.

Just like that.

jake


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careysub
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Re: Meteorite hits Russia, people injured new [Re: JayinUT]
      #5681967 - 02/15/13 04:59 PM

Quote:

Biggest impact since Tunguska is a rather large event. Imagine if it had come down in a major urban center. ...




As it is it came down over what was a closed military city devoted to the production of thermonuclear weapons. The only difference today is that it is not "closed". This had lots of potential for dangerous misinterpretations.

Quote:


Edit: On a side note this is probably the second largest impact since Tunguska if the NASA numbers hold. The third event is the Sikhote-Alin Meteorite that hit in eastern Siberia in 1947 in the then Soviet Union.




NASA is currently saying this is a 7000 ton object, far larger than the estimated 100 tons for Sikhote-Alin; and the largest over land since Tunguska.

An event this size hits Earth about every 40 years according to known meteor flux data. But remember that 75% of all meteor explosions occur over the ocean or uninhabited Antarctica. One of this size should occur over an inhabited continent every 160 years or so.

Tunguska was a genuinely rare event - about one per millenia event anywhere on Earth, or one-per-3000 years over land in current estimates.

The U.S. "Defense Support Program" (a "Manhattan Project" like non-descriptive name) recorded multiple kiloton size atmospheric explosions every year (the data was declassified from around 2000 to 2009 when they began reclassifying meteor intercept data).

Edited by careysub (02/15/13 06:16 PM)


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Achernar
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Re: Meteorite hits Russia, people injured new [Re: careysub]
      #5682019 - 02/15/13 05:28 PM

Yep, which could lead to an all-out nuclear war starting by mistake. Such an event over a large city or a sensitive military facility could be mistaken for a sneak attack. Missiles today can leave a target with little or no warning before they strike, and many of them can carry a neutron, chemical or nuclear warhead. It's very fortunate that the whole city was not destroyed, because Russia has a history of being the victim of sneak attacks, and retaliating with a devastating counter-attack against it's enemies. They are justly suspicious people when it comes to certain matters. Who knows what they would have done if an incoming asteroid did level a large Russian city killing millions.
Let's hope Putin and the military got good information about what was going on, because I have seen photos of re-entry vehicles plunging towards their targets, and they look just like that fireball, smoke trail and everything. The only way to tell an impact from space apart from nuclear explosions would be the fact an asteroid impact does not generate gamma rays and free neutrons, but a nuclear bomb will. Even worse nations such as India, Pakistan and North Korea have nuclear weapons, but do not have the early warning and space surveilliance systems we do, and a similar event over one of those countries can become a global nightmare.

Taras


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John Wunderlin
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Re: Meteorite hits Russia, people injured *DELETED* new [Re: careysub]
      #5682069 - 02/15/13 05:55 PM

Post deleted by John Wunderlin

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John Wunderlin
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Re: Meteorite hits Russia, people injured *DELETED* new [Re: John Wunderlin]
      #5682083 - 02/15/13 06:03 PM

Ok ignore my last posts... My napkin calculations were off.

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taylornate
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Re: Meteorite hits Russia, people injured new [Re: GlennLeDrew]
      #5682181 - 02/15/13 07:06 PM

Quote:

Do not base space motion *only* from trajectories as observed from a moving and rotating platform. The two principal components which have to be 'subtracted', as it were, are the Earth's own 29.7km/s motion and the location of the observer on the round Earth at the time of the event. The derived true space motion can differ quite substantially from the apparent motion.

In any event, I suspect this and DA14 to be unrelated. But we'll very soon know...




What is "true space motion" and what would be the relevance of it? Any measurement of velocity needs a reference frame, and in this situation I think ours would be the most relevant one.


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GlennLeDrew
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Re: Meteorite hits Russia, people injured new [Re: taylornate]
      #5682203 - 02/15/13 07:24 PM

Orbits are calculated with respect to the Sun, or more properly, I suppose, the barycenter of the Solar system, which is still inside the Sun. Two related bodies must therefore have quite similar orbital parameters, even if over time they have drifted some distance apart.

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GlennLeDrew
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Re: Meteorite hits Russia, people injured new [Re: GlennLeDrew]
      #5682208 - 02/15/13 07:27 PM

It just occurred to me... What might have resulted if an airliner were at altitude and more or less below the point of the airburst?

And could it be possible for some such situation in the past to have been the cause of a mysterious disappearance of an aircraft?..


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Re: Meteorite hits Russia, people injured new [Re: GlennLeDrew]
      #5682304 - 02/15/13 08:38 PM

Once while exiting a comutter jet I asked the pilot if he ever saw and/or thought about the possibilities of meteors hitting the aircraft. He said H*** yes, he had seen several go below his aircraft before they "popped".

Duhhh!


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Achernar
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Re: Meteorite hits Russia, people injured new [Re: GlennLeDrew]
      #5682379 - 02/15/13 09:21 PM

It would have been torn apart in mid air, and that of course would be the end for everyone aboard if it was close to the epicenter. But more likely, I would expect for every plane destroyed in this way, a larger number would be damaged or passengers and crew would see something. An interesting idea, since these blasts do occur over remote areas of ocean, and unpopulated areas, it might explain the disappearance of a few aircraft. But the only way it could be put to the test would be exhaustive studies of cases of aircraft gone missing and data collected by the military to see if any occurred at the right place and time frame. If an explosion occurred in an area where a lost aircraft was supposed to be, it should at least be circumstantial evidence to support it. Eye witness testimony and ground based RADAR would prove falling meteoroids could be a threat to aircraft.

Taras


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careysub
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Re: Meteorite hits Russia, people injured new [Re: StarStuff1]
      #5682434 - 02/15/13 09:54 PM

Quote:

Once while exiting a comutter jet I asked the pilot if he ever saw and/or thought about the possibilities of meteors hitting the aircraft. He said H*** yes, he had seen several go below his aircraft before they "popped".

Duhhh!




When the AirFrance airliner went down over the Atlantic quite mysteriously a few years ago one theory that was seriously considered was that it was hit by a meteor.

Calculations indicated that since the beginning of air travel there was a roughly 50% chance of a meteor strike on an aircraft occurring.


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taylornate
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Re: Meteorite hits Russia, people injured new [Re: GlennLeDrew]
      #5682540 - 02/15/13 11:03 PM

Quote:

Orbits are calculated with respect to the Sun, or more properly, I suppose, the barycenter of the Solar system, which is still inside the Sun. Two related bodies must therefore have quite similar orbital parameters, even if over time they have drifted some distance apart.




If you are thinking in terms of energy related to the collision, wouldn't the Earth be the most sensible reference frame? Unless I misinterpreted what you were replying to.


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careysub
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Re: Meteorite hits Russia, people injured new [Re: GlennLeDrew]
      #5682581 - 02/15/13 11:22 PM

Quote:

It just occurred to me... What might have resulted if an airliner were at altitude and more or less below the point of the airburst?

And could it be possible for some such situation in the past to have been the cause of a mysterious disappearance of an aircraft?..




Yes indeed it could down an airliner.

This is a scenario that has actually been considered as a serious candidate in at least two airliner crashes (Air France Flight 447 and TWA Flight 800).

One risk estimate was that there is a 50% chance of such an event downing an airliner through the cumulative history of commercial aviation to date.


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chrisg
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Re: Meteorite hits Russia, people injured new [Re: careysub]
      #5682704 - 02/16/13 01:15 AM

Wondering if its possible that any of the explosions heard were echos from sound waves bouncing off the top of the atmosphere. Could that happen?

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Re: Meteorite hits Russia, people injured new [Re: chrisg]
      #5682744 - 02/16/13 01:57 AM

NASA based on new data from a variety of sites has increased the mass from 7000 to 10,000 tons and from 49 feet long to 55 feet long. Paul Chodas of NASA said in the latest release that this is a 100 year event.

Quote:

"We would expect an event of this magnitude to occur once every 100 years on average," said Paul Chodas of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "When you have a fireball of this size we would expect a large number of meteorites to reach the surface and in this case there were probably some large ones."






See this link at NASA.

In terms of energy NASA is reporting on their site that this object exploded with:

Quote:

nearly 500 kilotons of energy released




I believe but someone can please correct me that that equals about.5 megatons? Not sure but I think that is right. Anyway, what an interesting day. I actually made a record of the day to remember it. Should be one for the history books.

Edit: If you want to see what a 500 kiloton nuclear blast would do you can go to this link which is to NukeMap, type in your city if it isn't there and set the yield to 500 and see the impact, it is huge! Talk about appreciating the energy expended in that impact with the atmosphere, wow!

Edit: I put in 5000 instead of 500 which is the correct amount. 500 is still a massive amount of energy. I corrected the amount.

Edited by JayinUT (02/16/13 06:05 AM)


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Dave Mitsky
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Re: Meteorite hits Russia, people injured new [Re: JayinUT]
      #5682830 - 02/16/13 05:00 AM

500 kilotons equals 0.5 megaton.

Dave Mitsky


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dan777
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Re: Meteorite hits Russia, people injured new [Re: JayinUT]
      #5682982 - 02/16/13 09:00 AM

Quote:

... what an interesting day. I actually made a record of the day to remember it. Should be one for the history books.



Indeed, this event and the transit of Venus within less than 12 months of each other and then the total solar eclipse passing across the US in 2017.


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Re: Meteorite hits Russia, people injured new [Re: dan777]
      #5683064 - 02/16/13 09:39 AM

S&T published this thoughtful and informative article on their website. The first video, which is a compilation, is pretty stunning.

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Re: Meteorite hits Russia, people injured new [Re: Special Ed]
      #5683082 - 02/16/13 09:50 AM

Just incredible videos! This morning a video from San Francisco showed a bright meteorite burning up in the night sky. What will the heavens bring next.

Jim


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careysub
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Re: Meteorite hits Russia, people injured new [Re: chrisg]
      #5683181 - 02/16/13 10:43 AM

Quote:

Wondering if its possible that any of the explosions heard were echos from sound waves bouncing off the top of the atmosphere. Could that happen?




Yes, definitely and in fact almost certainly. Large atmospheric nuclear explosions (and the current ~200 kt estimate of the Chelayinbk blast classifies it as large) often had shock wave "echo" zones in bands hundreds of kilometers from the explosion, far outside the normal limit of effects.

It is more like refraction than reflection though, sound waves being bent in natural wave-guide.


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Re: Meteorite hits Russia, people injured new [Re: careysub]
      #5683286 - 02/16/13 11:26 AM

Just curious where your getting 200 kilotons when NASA is reporting 500 kilotons. Do you have a link?

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Achernar
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Re: Meteorite hits Russia, people injured new [Re: JayinUT]
      #5683390 - 02/16/13 12:19 PM

Yes, .5 megatons is equal to 500,000 tons of TNT. That is a little more than the destructive power of just one of the eight nuclear warheads aboard a Trident D-5 missile carried by a our Trident submarines. That's enough to level a major city. In other words, a blast of this magnitude near the ground will destroy every building for several miles in every direction unless they are specially constructed military facilities. Even if the actual blast was closer to 200,000 tons of TNT, that still would have been the equivalent of a Tomahawk cruise missile carrying a nuclear warhead against a city. Russia was most fortunate this object exploded at a high altitude and not directly over Chelyabinsk. Fourty people are now in the hospital with serious injuries, and most of the 1,200 injured were cut by flying glass.

Taras


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Starhunter249
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Re: Meteorite hits Russia, people injured new [Re: Achernar]
      #5683448 - 02/16/13 12:43 PM

I was doing the math on how high this object was when it exploded. I calculated the altitude to be approx 20.4 miles above the earth. This is based on a video taken 300km away. The angle approx 5 degrees from the horizon. A sextant used at the location the video was shot would provide a more accurate measurement of angle above horizon. I could be way off on the angle; the angle could be larger which would increase its altitude at final explosion. I also took the curvature of the earth into account at 300km distance which is approx. 4 miles of additional height at horizon. I did not account for the elevation of the city of Chelyabinsk and the city of where the video was taken 300km away which could impact the calculation by a few miles.

What is also interesting is the time from the final flash and the shock wave heard. I have read various accounts from a minute to 3 minutes. Temperature and altitude effect the speed of sound and we are assuming the shock wave is traveling near or at the speed of sound. Colder air temperatures decreases wave velocity. Temperature at ground level was 4 degrees that morning and only gets colder as you ascend altitude until you reach the tropopause. The tropopause is a layer that separates the troposphere and the stratosphere. This is where the air is the coldest in the atmosphere. Above the tropopause is the stratosphere, the air temperature gets warmer as altitude increases, opposite of the troposphere. The air temperature at 20 miles above sea level is about -40 F. Speed of sound is about 0.19 miles per second. At ground level it was 4 degrees above zero which is about 0.20 miles per second. I dont know what the tropopause temperature is but you can assume its approx -70 F which is 0.184 miles per second. That would slow it down slightly compared to the -40 F at 100000 feet. We can ignore it. Assuming the shock wave is traveling at the speed of sound it would take as long as 107 seconds and as quick as 102 seconds. The true time is in between. As the wave is traveling thru warmer air, its speeding up. Air density does have a small slight factor on wave speed by it can be neglected for the purpose of estimates. If the meteor exploded at 10 miles as some experts of suggested, the interval would be half the time I estimated. Eye witness said it occurred several minutes later. If we can get an accurate time between flash and boom. We can get a better idea of the altitude of detonation.

Estimates of the energy released are about 300 kilotons. This is massive amount of energy, 30 times greater than the bomb dropped on Hiroshima. The troposphere which is about 11 miles at mid latitude absorbed much of the impact of the shock waves traveling first thru the stratosphere. If the explosion occurred inside the troposphere, this thing would be devastating to the city below. The Tunguska event, scientists estimate it detonated 3 to 6 miles above the earth and release 10 to 15 megatons of energy devastating 830 square miles of forest (from Wikipedia). Although the event on 2/15/2013 was much smaller in energy compared to Tunguska, the city below would have been severely damaged (not flattened like Tunguska)if the object exploded at 30,000 feet (5 miles) at 300 kilotons. At 10 to 12 miles above surface at 300 kilotons should result in more damage than blown windows and doors. I am not an expert in high altitude explosives but I believe this impact was higher in the atmosphere than preliminary estimates.


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hm insulators
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Re: Meteorite hits Russia, people injured new [Re: Achernar]
      #5683452 - 02/16/13 12:46 PM

I went out to my mother's house yesterday while all this was going on and one of the things that we discussed is that in our frantic, high-tech go-go-go world, we forget that we truly are connected to space. We discussed how so many of the ancient peoples of the world understood that we are part of a vast universe, from the ancient Babylonians, Egyptians and Greeks, the Native Americans (particularly the Mayans), and especially the Pacific Islanders, who were utterly superb navigators, using the stars to steer by and settle such places as Tahiti, Samoa and Hawaii.

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Re: Meteorite hits Russia, people injured new [Re: hm insulators]
      #5683493 - 02/16/13 01:05 PM

Peter Brown of the University of Western Ontario, Canada is giving an estimate of 300 kilotons but stating that can easily double as more data comes in. NASA continues to report it as a 500 kiloton event for now.

One thing I hope everyone remembers is that the NY Times is reporting that of those hospitalized 200 are children. May our thoughts go out to them and their families at this time.


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wirenut
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Re: Meteorite hits Russia, people injured new [Re: Mark9473]
      #5683633 - 02/16/13 02:25 PM

Quote:

No, this meteorite event in Russia is from a stone that traveled north-to-south; the asteroid 2012 DA14 (that you can now follow live at http://www.ustream.tv/nasajpl2 ) is going south-to-north.



I can't use that to rule things out cause I've seen during meteor showers 1 or 2 come 180 degrees from the radiant. I always thought they took the long way around for my viewing pleasure
hypothetical question, if a celestral body passing earth south -north got trapped by gravity but only enough velicity to make it pass the north pole have a impact trajectory in the north - south direction?
I don't think it should be ruled out on that reason alone it needs the math to go with it.


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Re: Meteorite hits Russia, people injured new [Re: JayinUT]
      #5683666 - 02/16/13 02:46 PM

Quote:

Just curious where your getting 200 kilotons when NASA is reporting 500 kilotons. Do you have a link?




Sky and Telescope reported it as 300 kilotons... http://www.skyandtelescope.com/news/home/Meteorite-Explodes-Over-Russia-19137... but also acknowledged NASA's estimate of 500 kilotons. I know that doesn't answer your question but thought I'd throw it out there.


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GlennLeDrew
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Re: Meteorite hits Russia, people injured new [Re: drbyyz]
      #5683727 - 02/16/13 03:27 PM

Wirenut,
These objects are traveling far too fast to effectively get 'trapped' in a partial orbit around Earth. They either just miss and fly by, with a *somewhat* altered path, or enter the atmosphere. No arcing around the planet to any significant degree.


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rdandrea
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Re: Meteorite hits Russia, people injured new [Re: drbyyz]
      #5683730 - 02/16/13 03:28 PM

Quote:

Sky and Telescope reported it as 300 kilotons..




That number was from yesterday afternoon's NASA conference call.

They have since revised size, mass, and explosive force upward.

http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130215.html


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BrooksObs
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Re: Meteorite hits Russia, people injured new [Re: GlennLeDrew]
      #5683758 - 02/16/13 03:45 PM

Regarding the amount of energy released in yesterday's event, the figures circulating are now so diverse that one can pick any number they wish and be considered OK.

Since early this morning I have seen reported in the news media by supposedly "knowledgeable scientific authorities" that the yield of the blast was "3 times the Hiroshima bomb", "200 kilotons"," 500 kilotons",and "3 megatons". That certainly is quite a range!

Likewise, a CNN science reporter gave the meteroid's dimension as about 10', elsewhere reported as 20', and the latest I've seen being 50'. At the same time the weight has ranged from 10 to 7,000 tons! The implication to me is that science has an awfully long way to go interpreting events of this sort with any meaningful accuracy.

BrooksObs

Edited by BrooksObs (02/16/13 03:46 PM)


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rdandrea
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Re: Meteorite hits Russia, people injured new [Re: BrooksObs]
      #5683774 - 02/16/13 03:55 PM

Quote:

The implication to me is that science has an awfully long way to go interpreting events of this sort with any meaningful accuracy.




Or maybe the media can't be bothered to report CURRENT numbers.


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Intensity2x
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Re: Meteorite hits Russia, people injured new [Re: rdandrea]
      #5683899 - 02/16/13 05:11 PM

Quote:

Or maybe the media can't be bothered to report CURRENT numbers.




I've seen quite a few news-casts / articles where I had first hand knowledge of the event itself and you would be amazed at how inaccurate most "news" is. And not minor mistakes either. Anything from a "news" source I would discredit entirely and stick to getting facts from places like NASA and the like. That said, there is still quite of wide range of numbers being given out by different agencies.


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GlennLeDrew
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Re: Meteorite hits Russia, people injured new [Re: Intensity2x]
      #5683946 - 02/16/13 05:45 PM

In last night's (Friday) 11PM CTV national newscast, the coverage stated that first it went dark as the meteor blocked the sun! I kid you not.

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Mike B
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Re: Meteorite hits Russia, people injured new [Re: GlennLeDrew]
      #5683957 - 02/16/13 05:52 PM



Yeah, something went dark, alright...

Just recently some friends were discussing clever sayings regarding foolish speach... many famous quotes may not be accurate at all, or be re-hashes of someone ELSE's quote- but many are excellent nonetheless. My personal fave:
The fool is one who, having nothing intelligent to say, provides everyone verbal evidence of the fact."

Case in point: this CTV newscaster.


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careysub
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Re: Meteorite hits Russia, people injured new [Re: JayinUT]
      #5684005 - 02/16/13 06:22 PM

They have upped their mass and yield estimate from their first report (from 7,000 tons to 10,000 tons).

But the 500 kT figure is too high if the mass and velocity are correct (10,000 tons, 18 km/sec). This gives a total kinetic energy of "only" 385 kT in the whole body.

The calculation is:
(10^7 kg*(18000 m/sec)^2)/2)*(4.2*10^12 J/kiloton) = 385 kT

Probably less than half of the original energy might be released at once in the main explosion, so really we are still looking at a ~200 kT blast.


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Starhunter249
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Re: Meteorite hits Russia, people injured new [Re: careysub]
      #5684176 - 02/16/13 08:19 PM

I think its odd that the Russian Scientists and the NASA scientists have numbers way off from each other. I think I'm gonna trust the Russians on the calculations rather than NASA. Russia still sends people into space, we (USA) don't anymore. I guess they did win the space race after all.

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careysub
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Re: Meteorite hits Russia, people injured new [Re: Starhunter249]
      #5684558 - 02/17/13 01:45 AM

Quote:

I think its odd that the Russian Scientists and the NASA scientists have numbers way off from each other. I think I'm gonna trust the Russians on the calculations rather than NASA. Russia still sends people into space, we (USA) don't anymore. I guess they did win the space race after all.




What Russian scientist numbers are you referring to? Official estimates of size and yield since Friday are conspicuous by their absence. Roscosmos is reported to reported a 30 km/sec velocity (much faster than NASA's 18 km/sec)- but I can't find any actual citation in English. Russian news is carrying the NASA estimates currently.

This explosion was picked up by a world-wide network of seismographs, and atmosphere shockwave stations set up and monitored internationally to detect nuclear tests. No one in the nuke monitoring community is disputing a 100 kiloton class explosion estimate.


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Re: Meteorite hits Russia, people injured new [Re: careysub]
      #5685306 - 02/17/13 02:09 PM

There is still something about these events that is still bothering me. It is being said that these two events, the meteorite & asteroid cannot be connected as they came from opposite directions. Could this have happened this way if the meteorite was in orbit around the asteroid?
I can imagine the meteoroid in a highly elliptical orbit striking the Earth in its 'return' trip, ahead of the near miss of the asteroid.


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GlennLeDrew
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Re: Meteorite hits Russia, people injured new [Re: brentwood]
      #5685363 - 02/17/13 02:47 PM

If DA14 had (or could possibly have) a companion in orbit, the orbit would have to be *extremely* small due to DA14's very small mass. By small orbit, I mean hardly larger than the body itself, as its tidal radius would not extend far. And such a situation could not last at all long against the tidal forces of the Sun and (occasionally) other planets.

On top of that, the orbital velocity would measured in perhaps cm/s, which compared to the pair's velocity of km/s is utterly minuscule. Therefore both bodies, either in mutual orbit or after being pulled apart, will have essentially identical space velocity and direction. There is no possibility of one coming at us from a direction different to any significant degree (allowing for the fact of the rotating Earth and location/time at impact introduces an additional velocity vector which must be subtracted.)


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Re: Meteorite hits Russia, people injured new [Re: brentwood]
      #5685366 - 02/17/13 02:49 PM

Quote:

There is still something about these events that is still bothering me. It is being said that these two events, the meteorite & asteroid cannot be connected as they came from opposite directions. Could this have happened this way if the meteorite was in orbit around the asteroid?
I can imagine the meteoroid in a highly elliptical orbit striking the Earth in its 'return' trip, ahead of the near miss of the asteroid.




To orbit something that is 50 meters across (DA14) would require you to be extremely close to it. If you got very far from it then the pull of the object (DA14) would be so tiny that the pull from other masses (say the Sun or Jupiter) would be much larger and you would leave the orbit.

I calculate that the orbital period around DA14 (using 190,000 metric tons for its mass) would be 15.5 hours if you were only 100 meters away from the center of it. It would be 20.4 days if you were one kilometer away. If you were 384,000 km (the distance from Earth to the Moon) then the period would be 13.3 million years.


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Re: Meteorite hits Russia, people injured new [Re: WarmWeatherGuy]
      #5685523 - 02/17/13 04:53 PM

Thank you both, that is a much better answer than I got from CNN! or NASA !

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Re: Meteorite hits Russia, people injured new [Re: brentwood]
      #5685537 - 02/17/13 05:01 PM

Like they didn't see this one coming. Even if there was an asteroid or meteor was going to strike the earth. They would never tell us, think of the civil chaos that would ensue. Societal break down and strickened wide panic. And then after the fact, they have the odacity to address the general public looking like idiots, saying they didn't know it was coming and infer the need for more funding in space exploration. Way to go JPL and NASA.

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GlennLeDrew
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Re: Meteorite hits Russia, people injured new [Re: Saclablue]
      #5685567 - 02/17/13 05:19 PM

Saclablue,
That's a somewhat cynical attitude. Small bodies like this (generally kind of dark) vehicle-sized meteoroid can only be detected when awfully nearby already. And if their approach vector has them coming from the general direction of the Sun, the combination of atmospheric twilight, zodiacal light, solar corona (within a couple or few degrees of the disk) and that we see predominantly the body's night side, the visibility goes down to practically zero until already hitting the atmosphere.


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Michaelo
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Reged: 12/21/12

Re: Meteorite hits Russia, people injured new [Re: CharlesW]
      #5686119 - 02/17/13 10:44 PM

I was looking for reports of recent events in order to determine what I saw Feb 17th at approximately 19:00...

While setting up my scope I saw a seriously big fireball...
I was looking westward at the moon using binoculars, and it crossed my field of view (from south to north and appeared to be falling)...

No idea what it was but expect some news report as it was (or appeared to be) seriously big...

If it was a meteor, then is there a storm due?


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rdandrea
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Re: Meteorite hits Russia, people injured new [Re: Michaelo]
      #5686694 - 02/18/13 09:53 AM

Michaelo, it would help people figure out what you saw if you would give your location.

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GlennLeDrew
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Re: Meteorite hits Russia, people injured new [Re: rdandrea]
      #5687093 - 02/18/13 03:00 PM

Michaelo,
Very bright fireballs/bolides are usually stony or iron bits of asteroidal debris, all on their 'lonesome', so to speak. They can enter the atmosphere at any angle, and occur randomly.

Meteor showers (or storms when very active) are mostly bits of dust scattered along the orbits of comets which we happen to intersect. A shower can last from hours to weeks, depending on how widely the cometary debris has spread. All related meteors if a particular shower appear to come from the same point on the sky.


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Tony Flanders
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Re: Meteorite hits Russia, people injured new [Re: Saclablue]
      #5688342 - 02/19/13 05:24 AM

Quote:

Even if there was an asteroid or meteor was going to strike the earth. They would never tell us, think of the civil chaos that would ensue.




That is demonstrably untrue. In all of history, there has been precisely one meteroid that was detected in space and subsequently struck Earth: 2008 TC3. And the discovery was indeed announced immediately.

As time goes on and the surveys become more sensitive, this will surely happen more often.

Neither the Sudan meteoroid nor the one that exploded over the Urals was big enough to cause regional damage, much less planet-scale damage. It's believed that all or almost all planet-threatening asteroids are already known and tracked.

Comets are a different matter.


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