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https://en.wikipedia.org/wiki/Chelyabinsk_meteor https://en.wikipedia.org/wiki/Chelyabinsk_meteor > The Chelyabinsk meteor was a superbolide that entered Earth

by retrac 4y ago

https://en.wikipedia.org/wiki/Chelyabinsk_meteor https://en.wikipedia.org/wiki/Chelyabinsk_meteor > The Chelyabinsk meteor was a superbolide that entered Earth's atmosphere over the southern Ural region in Russia on 15 February 2013 at about 09:20 YEKT (03:20 UTC). It was caused by an approximately 18 m (59 ft) diameter, 9,100-tonne (10,000-short-ton) near-Earth asteroid that entered the atmosphere at a shallow 18.3 ± 0.4 degree angle with a speed relative to Earth of 19.16 ± 0.15 kilometres per second (69,000 km/h; 42,690 mph). > [...] The asteroid had a total kinetic energy before atmospheric impact equivalent to the blast yield of 400–500 kilotons of TNT (about 1.4–1.8 PJ), estimated from infrasound and seismic measurements. This was 26 to 33 times as much energy as that released from the atomic bomb detonated at Hiroshima. If it had been at a slightly sharper angle, or slightly larger, or moving slightly faster, and if it had hit the right location, it could have destroyed a city. Fortunately it disintegrated in the upper atmosphere, so it only blew out windows across a large area as it burned brighter than the sun across the sky. There was no warning. The Tunguska rock, if it was a rock, was only a few times wider. I don't think we can reliably detect those, either.

grogenaut 4y ago
Do you actually need to have detected it as it was coming in to be able to say 15 minutes later "oh that was a meteor" detection and forensics are different... it's just really if the forensics happen fast enough to avoid a counter strike. Eg if some nuclear capable countries capitol just evaporated with no nuke early warning systems going off and no one could look up and see the massive trail coming in and had not streamed it on the internet first.
- ianburrell 4y ago
  There is space surveillance network tracks things in orbit. I don't think that covers all of the sky and could miss a rock. There are early warning satellites that look down for ballistic missiles. I don't know if the infrared detectors would see the rock. They are probably best as negative signal with no rocket being detected. The main signal that wasn't nuclear weapon would be the size and location. Nuclear weapons don't explode as high as Chelyabink meteor. Nuclear weapons aren't as big as Tunguska event. Also, hitting a city is unlikely, hitting one dead on is really unlikely. There would also no nuclear fallout detected.
  - jcrawfordor 4y ago
    Space-based nuclear weapons surveillance systems monitor for X-ray burst and the characteristic double-flash pattern. Neither would be present in the case of a meteor, which would rule out a nuclear detonation immediately. Infrared systems likely would detect the meteor entering but the projected flight path would be, well, unreasonable for a missile.

by retrac 4y ago

grogenaut 4y ago

Do you actually need to have detected it as it was coming in to be able to say 15 minutes later "oh that was a meteor" detection and forensics are different... it's just really if the forensics happen fast enough to avoid a counter strike. Eg if some nuclear capable countries capitol just evaporated with no nuke early warning systems going off and no one could look up and see the massive trail coming in and had not streamed it on the internet first.

ianburrell 4y ago
There is space surveillance network tracks things in orbit. I don't think that covers all of the sky and could miss a rock. There are early warning satellites that look down for ballistic missiles. I don't know if the infrared detectors would see the rock. They are probably best as negative signal with no rocket being detected. The main signal that wasn't nuclear weapon would be the size and location. Nuclear weapons don't explode as high as Chelyabink meteor. Nuclear weapons aren't as big as Tunguska event. Also, hitting a city is unlikely, hitting one dead on is really unlikely. There would also no nuclear fallout detected.
- jcrawfordor 4y ago
  Space-based nuclear weapons surveillance systems monitor for X-ray burst and the characteristic double-flash pattern. Neither would be present in the case of a meteor, which would rule out a nuclear detonation immediately. Infrared systems likely would detect the meteor entering but the projected flight path would be, well, unreasonable for a missile.