Collided Satellite Debris Coming Down?

Jamie found this Bad Astronomy blog on the many reports beginning about 7 hours ago of one or more fireballs in the sky across Texas. That blog's proprietor first doubted that the phenomena could be due to the satellites that collided in orbit last week, but later left the possibility open. The National Weather Service for Jackson, KY put out an announcement about possible explosions and earthquakes across the area and blamed the defunct satellites. "These pieces of debris have been causing sonic booms...resulting in the vibrations being felt by some residents...as well as flashes of light across the sky. The cloud of debris is likely the result of the recent in orbit collision of two satellites on Tuesday...February 10th when Kosmos 2251 crashed into Iridium 33." An Austin TV station has more reports.

nice view

[Criliric]

now this would be a cool sight to see, i'm hoping nobody gets hurt from all of this

After seeing the video he says its a meteor

[bitcastle]

"I can now state unequivocally that this is not the result of the satellite collision. The meteor is moving far too quickly for that; satellite collision debris would fall at perhaps 10 km/sec max, while incoming meteoroids are moving at 11km/sec at a minimum, and this thing is screaming across the sky at several dozen km/sec (assuming itâ(TM)s at a typical meteor height of 50 or more km). So I was probably right in the first place, and what we have here is almost certainly a single object, perhaps a meter or two across, and it came from deep space"

it figures...

[yodleboy]

just like columbia, i slept through the whole thing. need to come up with a business plan for notifying people in the event of space debris showers...

Re:After seeing the video he says its a meteor

[daemonburrito]

Most recent entry [discovermagazine.com]

The sky is falling!

[defiek]

It can only stay up there so long. I read somewhere that they estimated a bulk of the debris will stay in orbit for 10,000 years.

Re:Sky is falling

[Anonymous Coward]

Debris thrown into a higher orbit will last almost indefinitely orbits greater than 1,000km have lifetimes of thousands of years. Debris that is accelerated into a lower orbit has lifespans of day to months, anything less than 100km will last less than a year.

I was interviewed by lex18 news about this yesterday, I work with the 21m space tracking system at Morehead State University, and have been studying orbital mechanics in advance of the launch of our cubesat KYSAT1

Re:You don't undertstand orbital physics

[sjames]

A head on collision IS extremely unlikely, which is why you can have some parts re-enter so soon. Imagine a glancing collision where one satellite strikes the upper half of the other. The result can be a highly eccentric path that intersects the atmosphere. An additional factor could be if a pressurization tank bursts in the collision.

Re:earthquakes?

[andy_t_roo]

yep - just a little overrated.
Objects in low earth orbit have 32.1 to 38.6 MJ/kg [wikipedia.org] energy. Assuming that the collision between 2 1000kg satellites leaves 1/2 the energy left over, there's potentially 3.8e10J of energy. 1g of TNT is defined as 4184J [wikipedia.org] therefore the left over energy is equal to 9.2T of tnt, minus what is lost as objects pass through the atmosphere, what was used to break the satellite up, etc...

To put this into scale, if all this energy was to go off at one point in an earthquake, to cause the rumblings in TFA, it would be around mangitude 2.7 [wikipedia.org] or so, of which there are about a thousand per day and are generally not felt.

This is discounting that the satellite broke into quite a few pieces which will gradually enter the atmosphere over the next while.

Re:Kv

[c6gunner]

If you're near a couple of tons at reentry speed, yeah. I'll bet you'd think it was an earthquake too.

Except that none of the pieces would be anywhere NEAR that size. The iridium satellite was about half a ton, and the Russian satellite weighed in at just under a ton. Even if they had fused into one solid mass on impact, you still wouldn't have enough material to make up "a couple of tons".