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The entire world would have detected the meteor that large and been warned

andrewl 4y ago
The Wikipedia page for the Tunguska event says it was “a stony asteroid about 50–60 metres (160–200 feet) in size.” How far out would something that size be detected? This is very much out of my area.
- kzrdude 4y ago
  The other mentioned much smaller one has a whole article on it https://en.wikipedia.org/wiki/2023_CX1 https://en.wikipedia.org/wiki/2023_CX1 This one was 1 m wide and it seems like it was detected about 6 hours before coming down.
  - ale42 4y ago
    But, as someone mentioned in another comment, the fact that we can detect a 1 m objects doesn't mean that we can detect all of them, far from that. Same for larger ones, we just have more chances of detecting those than 1 m-sized ones.
adastra22 4y ago
No, we routinely get hit by rocks we didn’t see coming.
JoeDaDude 4y ago
Detecting incoming asteroids, especially small ones, is really hard. The recent 1-meter meteor that exploded over Europe, was only the seventh instance of a successful detection. https://www.telegraph.co.uk/science/2023/02/13/asteroid-explodes-english-channel-rare-early-detection/ https://www.telegraph.co.uk/science/2023/02/13/asteroid-expl...
- hutzlibu 4y ago
  But it is the big ones, we are interested in, because they can do a lot of damage and not only fireworks.
- kwhitefoot 4y ago
  Tunguska was a lot bigger than a metre across. Even the Chelyabinsk meteorite was a lot bigger, 18 m diameter, 9 000 tonne. So if we cn detect 1 m meteors I think we should be able to detect Tunguska scale objects.
  - btilly 4y ago
    We may notice some small things, but that doesn't mean that we've found all large things. According to https://www.nasa.gov/planetarydefense/faq https://www.nasa.gov/planetarydefense/faq we only know about 40% of the rocks sized 140 meters+ that cross Earth's orbit. If one of the 60% we don't know about came at us from the direction of the Sun, our odds of seeing it before impact are fairly small.
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.

The Wikipedia page for the Tunguska event says it was “a stony asteroid about 50–60 metres (160–200 feet) in size.” How far out would something that size be detected? This is very much out of my area.

kzrdude 4y ago
The other mentioned much smaller one has a whole article on it https://en.wikipedia.org/wiki/2023_CX1 https://en.wikipedia.org/wiki/2023_CX1 This one was 1 m wide and it seems like it was detected about 6 hours before coming down.
- ale42 4y ago
  But, as someone mentioned in another comment, the fact that we can detect a 1 m objects doesn't mean that we can detect all of them, far from that. Same for larger ones, we just have more chances of detecting those than 1 m-sized ones.

adastra22 4y ago

No, we routinely get hit by rocks we didn’t see coming.

JoeDaDude 4y ago

Detecting incoming asteroids, especially small ones, is really hard. The recent 1-meter meteor that exploded over Europe, was only the seventh instance of a successful detection. https://www.telegraph.co.uk/science/2023/02/13/asteroid-explodes-english-channel-rare-early-detection/ https://www.telegraph.co.uk/science/2023/02/13/asteroid-expl...

hutzlibu 4y ago
But it is the big ones, we are interested in, because they can do a lot of damage and not only fireworks.
kwhitefoot 4y ago
Tunguska was a lot bigger than a metre across. Even the Chelyabinsk meteorite was a lot bigger, 18 m diameter, 9 000 tonne. So if we cn detect 1 m meteors I think we should be able to detect Tunguska scale objects.
- btilly 4y ago
  We may notice some small things, but that doesn't mean that we've found all large things. According to https://www.nasa.gov/planetarydefense/faq https://www.nasa.gov/planetarydefense/faq we only know about 40% of the rocks sized 140 meters+ that cross Earth's orbit. If one of the 60% we don't know about came at us from the direction of the Sun, our odds of seeing it before impact are fairly small.

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.