Meteoroid explosion in Russia

[Sky Captain]

A 30 km/s speed would indicate this rock had very ellyptical or very inclined orbit, so not a typical near Earth asteorid.

 

[Urwumpe]

A 30 km/s speed would indicate this rock had very ellyptical or very inclined orbit, so not a typical near Earth asteorid.

Exactly. It is also not related to a known meteor family, that has connections to a comet. It was really a bolt from the blue. The local time of the event (9:30) and the east-to-west travel also suggests that the object came from the approximate direction of the sun towards Earth and was impossible to spot by astronomers in the days before impact.

 

[Kyle]

More video coming in.
http://www.youtube.com/watch?feature=player_embedded&v=0ozSq3yEm3g

 

[Radu094]

Ok, something's been puzzling me about the impact being at 9:30 am. So either the object was orbiting prograde but at a slower vel than Earth's, or it was retrograde. Both of which, I imagine, are pretty unlikely...

I was always under expectation that a big asteroid should impact between 12pm and 12am local time. You can't even count on asteroids to be on time...

 

[Urwumpe]

Ok, something's been puzzling me about the impact being at 9:30 am. So either the object was orbiting prograde but at a slower vel than Earth's, or it was retrograde. Both of which, I imagine, are pretty unlikely...

I was always under expectation that a big asteroid should impact between 12pm and 12am local time. You can't even count on asteroids to be on time...

It was travelling at 30 km/s and was coming at the current state of information from the inner solar system, very close to the sun. It must not be retrograde at such eccentricity, it could also just pass the Earth at this side.

The apohelion must not even be very high, to produce such a impact velocity after acceleration by Earths gravity. Maybe around Mars. But the perihelion must have been very low.

 

[Radu094]

...But the perihelion must have been very low.

Isn't that kinda rare/unusual? Granted, this has been a long time ago, but I distinctly remember something on disk accretion about the imposibility of asteroids either forming or remaining in low perihelion (or inner solar systems) orbits, and that they preffer the quieter and colder places of mid-to-outer orbits

 

[csanders]

Has its velocity been confirmed? I'm hearing either around 30k mph, or 30k m/s.

 

[Sky Captain]

Isn't that kinda rare/unusual? Granted, this has been a long time ago, but I distinctly remember something on disk accretion about the imposibility of asteroids either forming or remaining in low perihelion (or inner solar systems) orbits, and that they preffer the quieter and colder places of mid-to-outer orbits

It is possible the original orbit was altered in previous close encounters with Earth or Venus creating an orbit with very low perihelion.

 

[RisingFury]

Has its velocity been confirmed? I'm hearing either around 30k mph, or 30k m/s.

30 000 miles per hour is possible, but it's at the lowest limit of velocity an asteroid can have. Keep in mind that an asteroid cannot come in slower than 11 km / s and 30 000 mph is roughly 13 km / s.

Though the explosion was quite devastating, so if the velocity was this low, the mass would have been 5 times higher for the same energy.

 

[FordPrefect]

Wow, what an eerie event.

New video in HD (found by SpaceEngineer on the SpaceEngine Forums), you can see the atmospheric entry at 04:30 min. and the blast wave at 07:00 min runtime.

http://youtu.be/gQ6Pa5Pv_io

 

[Ripley]

NASA statement on Russian meteor:

"According to NASA scientists, the trajectory of the Russian meteorite was significantly different than the trajectory of the asteroid 2012 DA14, making it a completely unrelated object. Information is still being collected about the Russian meteorite and analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14's trajectory is in the opposite direction, from south to north."

http://www.nasa.gov/topics/solarsystem/features/asteroidflyby.html

 

[RisingFury]

Wow, what an eerie event.

New video in HD (found by SpaceEngineer on the SpaceEngine Forums), you can see the atmospheric entry at 04:30 min. and the blast wave at 07:00 min runtime.

http://youtu.be/gQ6Pa5Pv_io

From the video you can estimate the altitude at which the meteorite exploded:

Meteorite explodes at 4:40 in the video and the sound arrives at about 7:00 in the video, giving a 2 minute and 20 second (140 second) travel time. At 320 m/s, the distance from the detonation is about 45 km.

The angle from the ground is a bit tricky to estimate, but assuming 30° gives you an explosion altitude of 22 km, assuming 45° altitude gives you about 32 km. So the explosion probably occurred between 20 and 35 km altitude.

Now that we have the distance to the object, it's also possible to give a rough estimate of its velocity.

In about 3 seconds, the meteorite travels from the top right corner, to the top middle of the screen. Again, the visual angle is just an estimate but I'd say that side to side the video is about 90°. So the meteorite traveled about 45° in 3 seconds, at a distance of about 45 kilometers.

From that, I get a rough estimate of 11 km/s at the time of detonation, but this estimate varies wildly based on my estimate of distance to the meteorite, estimate of speed of sound, estimate of visual field of the camera and does not take into account deceleration and the fact that initially the meteorite appears to be closer to the camera. I also simplified the geometry and the velocity given by the estimate is therefore lower. I'm estimating the velocity between 10 and 20 km / s at the time of detonation.

 

[sitha241]

Where was ISS on that time?

 

[Scorpius]

Where was ISS on that time?

At 3:25 UTC (asteroid breakup) it was above Pacific Ocean:

 

[statickid]

So one source (sorry I forgot where) said the primary shockwave was actually just from it travelling and the explosion and break apart, though visually impressive wasn't the source of the main shock. 2 cents anyone?

 

[Urwumpe]

So one source (sorry I forgot where) said the primary shockwave was actually just from it travelling and the explosion and break apart, though visually impressive wasn't the source of the main shock. 2 cents anyone?

Doubtful. The object was at 30-40 km altitude, that creates a rather silent sonic boom. The similar sized, but slower Space Shuttle, was almost impossible to hear at that altitude. And the fragmentation event would in any case produce a very strong sound, much louder than the sonic boom, so, even if the fragmentation wouldn't be the first event that you hear, it would be very very loud.

 

[Cairan]

A friend just put into image what we've been reading about some russian forces claiming to have shot down the meteor

 

[asbjos]

A guy in a Norwegian environmentalist group called 'Bellona' now says that it was 'griseflaks' (translated to 'very lucky', but literally: pig luck) that the meteorite didn't explode over a nuclear power plant not far away, which would then 'probably give a nuclear accident at the size of Chernobyl incident'.

I think the guy saying that should read a little bit about probability one more time before he published such things. :facepalm:

 

[SiberianTiger]

 

[Urwumpe]

A guy in a Norwegian environmentalist group called 'Bellona' now says that it was 'griseflaks' (translated to 'very lucky', but literally: pig luck) that the meteorite didn't explode over a nuclear power plant not far away, which would then 'probably give a nuclear accident at the size of Chernobyl incident'.

I think the guy saying that should read a little bit about probability one more time before he published such things. :facepalm:

well - regarding my experience with really existing nuclear power plants in the past decades, I would say, they are not right, but also not wrong.

A good well-tended, properly operated nuclear power plant would have no problems. But such nuclear power plants only exist in dreams. Even the best nuclear power plants are compromises between safety and economy. Some critical components are always placed at the wrong point.

if the explosion would have happened low above even a good power plant, it could result in problems maintaining a safe shutdown. Not automatically a Chernobyl. But close enough to worry.