Meteoroid explosion in Russia

[BruceJohnJennerLawso]

It basically reduces the amount of energy that can be absorbed by the atmosphere via friction and pressure waves. The atmosphere is only ~100 km thick from top to bottom. Coming in at a tangent it might have to pass through many hundreds of km of air.

A direct trajectory means a greater likelihood that the impactor will actually hit the surface and will hit with a significant fraction of its mass and energy remaining.

Here's what a 500 kiloton explosion looks like (Ivy King shot, largest fission bomb, 1952) which might give an upper limit example of what could have happened last week:

IVY KING: THE ROYAL ATOM BOMB - YouTube

Well that sounds somewhat plausible, but a head on reentry in a DGIV would vaporize it, whereas a shallower angle allows more of it to survive to hit the surface. Could that apply in this case, or does the scale factor ensure that some high-speed debris will still survive anyways? (Asteroid is a lot more mass than DGIV you know )

 

[Thunder Chicken]

Well that sounds somewhat plausible, but a head on reentry in a DGIV would vaporize it, whereas a shallower angle allows more of it to survive to hit the surface. Could that apply in this case, or does the scale factor ensure that some high-speed debris will still survive anyways? (Asteroid is a lot more mass than DGIV you know )

There is a parameter called the [ame="http://en.wikipedia.org/wiki/Ballistic_coefficient"]ballistic coefficient[/ame] that describes this, basically the ratio of the object's inertia to the drag on the object.

Small dense objects (metallic meteors) have a higher ballistic coefficient than larger, less dense objects (stony meteors), even though both may have the same total mass and velocity (i.e. same energy).

The Russian meteor was apparently a more stony type, which means a lower ballistic coefficient, which means that atmospheric drag was more effective at absorbing its kinetic energy. Had it been an iron-rich meteor of the same mass and velocity it may well have reached the surface.

 

[Screamer7]

How does this meteor explosion compare with the Tunguska event in 1908?

 

[Linguofreak]

How does this meteor explosion compare with the Tunguska event in 1908?

Tunguska had a yield between 6 and 60 times higher, most likely in the range of 20 to 30 times higher, according to the yield estimates given in the Wikipedia articles on the two events.

 

[Ripley]

Not that I endorse the UFO/missile/thought-driven-laser/whatever "exotic" theory, but in this video (at around 0:40) you can see the meteoroid "breaking apart", or something like that (sorry for my ignorance).

And yes, that ever-lagging pointer is dead annoying.

 

[garyw]

Not that I endorse the UFO/missile/thought-driven-laser/whatever "exotic" theory, but in this video (at around 0:40) you can see the meteoroid "breaking apart", or something like that (sorry for my ignorance).
http://www.youtube.com/watch?v=3ZzG881Vii8

The Asteroid was attacked by the atmosphere. that's what caused it to fragment and break apart.

 

[RGClark]

Just because something has a low probability of happening does not mean it cannot happen.
Your proposed explanation is incorrect on pretty much every point you make. In short, nothing can produce the required delta-v at the last minute in order to explain the different orbits of the two objects and still preserve the objects intact.
Outgassing or loosely bound asteroid torn by gravity would only produce small change of velocity, but an impact with another body would completely destroy both bodies - remember what happened the last time two satellites collided...
...

It wasn't at the last minute. The fragment got separated from the asteroid, then a close encounter occurred with a gravitating body that changed it's orbit from that of the asteroid. Then on the next orbit or a subsequent orbit it impacted the gravitating body.

Bob Clark

 

[Urwumpe]

It wasn't at the last minute. The fragment got separated from the asteroid, then a close encounter occurred with a gravitating body that changed it's orbit from that of the asteroid. Then on the next orbit or a subsequent orbit it impacted the gravitating body.

Bob Clark

Very unlikely since you would need many such lucky passes for getting from a NEO to an asteroid belt orbit.

It was by composition and trajectory an classic asteroid belt meteoroid. it likely resulted from an collision in the belt and spend some million years passing the inner solar system.

 

[garyw]

It wasn't at the last minute. The fragment got separated from the asteroid, then a close encounter occurred with a gravitating body that changed it's orbit from that of the asteroid. Then on the next orbit or a subsequent orbit it impacted the gravitating body.

Bob Clark

If it happened about 30 million years ago I'd say you were right. What else could account for the totally different orbit, speed, size, entry angle, position, timing, etc.

 

[jedidia]

It wasn't at the last minute. The fragment got separated from the asteroid, then a close encounter occurred with a gravitating body that changed it's orbit from that of the asteroid. Then on the next orbit or a subsequent orbit it impacted the gravitating body.

That would still make it pure coincidence that it hit at the same time, and as such it would be rather irrelevant if it was a part of the same asteroid once upon a time.

 

[RisingFury]

It wasn't at the last minute. The fragment got separated from the asteroid, then a close encounter occurred with a gravitating body that changed it's orbit from that of the asteroid. Then on the next orbit or a subsequent orbit it impacted the gravitating body.

Bob Clark

No, impossible. If they separated long ago, then even the smallest difference in velocity over time would produce huge distances. They then wouldn't hit the same day.

You seem to be clinging on to this impossibility instead of accepting the facts.

 

[Ghostrider]

It's quite simply, really: the Cosmos threw a big shiny asteroid one way to have them look at it, while it rabbit-punched us in the kidneys with the meteor.

The Cosmos is Serious Business.

 

[Notebook]

A slight aside - why does it seem that everyone in Russia has a dashboard camera? Just curious.

More dash-cams!

http://www.guardian.co.uk/world/video/2013/feb/15/russian-roads-dash-cams-video

N.

 

[Screamer7]

More dash-cams!

http://www.guardian.co.uk/world/video/2013/feb/15/russian-roads-dash-cams-video

N.

And I thought South African drivers were bad!!! :facepalm:

 

[RGClark]

No, impossible. If they separated long ago, then even the smallest difference in velocity over time would produce huge distances. They then wouldn't hit the same day.

You seem to be clinging on to this impossibility instead of accepting the facts.

The asteroid 2012 has a close orbit to that of the Earth so close encounters occur yearly. This year's just happened to be particularly close.

Bob Clark

---------- Post added at 09:59 AM ---------- Previous post was at 09:56 AM ----------

If it happened about 30 million years ago I'd say you were right. What else could account for the totally different orbit, speed, size, entry angle, position, timing, etc.

Keep in mind that a body coming in close to the Earth can get a delta-V boost close to that of escape velocity of 11.2 km/s. This can result in a large change in the orbit.

Bob Clark

 

[garyw]

Keep in mind that a body coming in close to the Earth can get a delta-V boost close to that of escape velocity of 11.2 km/s. This can result in a large change in the orbit.

Bob Clark

It wasn't close to the Earth until it hit it. These two rocks are unrelated.

Have a look at this:

Five hours ago ->

153460 2001 RN, ~370m-820m in diameter, just passed the Earth at 18km/s, missing by ~23,300,000km

Yesterday ->

2013 CZ87, ~18m-39m in diameter, just passed the Earth at 7km/s, missing by ~2,690,000km

Two more rocks went by the Earth. Neither are part of DA14 2012. These things happen on a daily basis.

 

[RGClark]

It wasn't close to the Earth until it hit it. This two rocks are unrelated.

Have a look at this:

Five hours ago ->

153460 2001 RN, ~370m-820m in diameter, just passed the Earth at 18km/s, missing by ~23,300,000km

Yesterday:

2013 CZ87, ~18m-39m in diameter, just passed the Earth at 7km/s, missing by ~2,690,000km

Two more rocks went by the Earth. Neither are part of DA14 2012. These things happen on a daily basis.

That the meteor and asteroid were both large and got so close was what was so notable about them. That they both occurred within the same 24 hour period make them extraordinarily unlikely.

These scientists both came to highly unlikely probabilities for this occurrence:

[FONT=Courier, Monospaced]A meteor and asteroid: 1 in 100 million odds.
By Meg Urry, Special to CNN
updated 8:16 PM EST, Mon February 18, 2013
http://www.cnn.com/2013/02/16/opinion/urry-meteor-asteroid/index.html
[/FONT]
Meteor over Russia causes shock waves that injure at least 950 Posted by: Dr. Jeff Masters, 3:12 PM GMT on February 15, 2013

According to NASA (as posted on spaceweather.com), "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." The odds of the largest meteor strike in 100 years occurring on the same day as the closest asteroid approach in 15 years are about 1 in 200 million, assuming these events are not correlated--truly a cosmic coincidence!
http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2350

Bob Clark

 

[Urwumpe]

The odds are much lower that you have 7 numbers right, ranging from 1 to 50. Still people play lottery and win often enough.

That something unlikely happened is no sign of it being no coincidence. If you always use the birth dates of your family for lottery and play every week and win once after 20 years of playing, this is no evidence of you having been born on an especially lucky day.

 

[statickid]

odds of 1 in 10 x 10^n is still non-zero. improbable not impossible. if those have been the odds every "day" for 10 million years then it's FINALLY about TIME it happened

 

[Thunder Chicken]

It wasn't close to the Earth until it hit it. This two rocks are unrelated.

Have a look at this:

Five hours ago ->

153460 2001 RN, ~370m-820m in diameter, just passed the Earth at 18km/s, missing by ~23,300,000km

Yesterday:

2013 CZ87, ~18m-39m in diameter, just passed the Earth at 7km/s, missing by ~2,690,000km

Two more rocks went by the Earth. Neither are part of DA14 2012. These things happen on a daily basis.

Take a look at this video. This shows many (not all) of the asteroids that we actually know about.

[ame="http://www.youtube.com/watch?v=S_d-gs0WoUw&feature=relmfu"]Asteroid Discovery From 1980 - 2010 - YouTube[/ame]

They are finding more every day, and there is a lot of big stuff that simply is missed.