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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.
As someone noted above, I'm now very sure this was a natural piece of cosmic debris, a chunk of asteroid or something similar. I posted a wrapup with my thoughts.
*** Phil Plait, aka The Bad Astronomer http://www.badastronomy.com
RTFA carefully. Citizens are reporting sounds and vibrations they -think- are earthquakes etc. but authorities are saying it is just caused by the sonic booms of stuff (whatever it is) entering the atmosphere and exploding.
Seismometers detect things like sonic booms and lightning strikes from quite large distances away.
So if it created a sonic boom coming down through the atmosphere it could have been detected as seismic activity.
The FAA issued a Notice To Airmen yesterday predicting debris and asking pilots to report.
I think there may be some conflict between the FAA's safety concerns and NORAD's secrecy. NORAD will weigh in eventually (when they're sure what they can and can't say), but there no reason to throw away the FAA's opinion, even though they are not the "go to" agency.
Well, we were warned...
ZOMBIES AHEAD!
LEO is between 160 and 2000 km.. therefore 600 is in the low end of LEO.
How we know is more important than what we know.
Getting hit by a meteorite is pretty unlikely. The only well documented case happened in 1954, and it only resulted in a bruise.
There are many times more natural meteorites than artificial ones, so it's unlikely that anyone will be hurt by space debris meteorites.
(Also posted to Bad Astronomy.)
A simple orbital analysis using the ground tracks from, e.g. Heavens-Above.com shows that this was not debris form the collision.
The debris from a collision keeps more or less the same orbit as before, but is spread out along the orbit. (Orbital plane changes require a lot more delta-v than changing the along-track position or altitude, since drift along the orbit accumulates, but displacements across the orbit swing back and forth with each cycle.)
Looking at the ground tracks of
Iridium 33 and
Cosmos 2251
Just eyeballing the tracks, the North-going leg of the orbit of Iridium 33 crosses the latitude of Texas at around 10 PM local time. For Cosmos 2251, it crosses about 4 PM local.
An 11 AM fireball could be Iridium debris, but only if it were heading to the south-south-east. The fireball was heading NNE. So this was NOT debris from either satellite.