13 ms·

The Tunguska Event

138 points by jackgavigan 10y ago

bpicolo 10y ago
You have to wonder when a large piece of space rock will hit somewhere inhabited. That said, with 3% of earth's land being urban (3% of 29% of Earth), and reasonably infrequent falling rocks, it's really not that likely to happen in any given lifetime. I suspect we're keen enough these days to be able to predict and evacuate the right areas, though. This paper references another that suggests a "Tunguska Event" is a once in 200-300 year deal: http://articles.adsabs.harvard.edu//full/1994Metic..29..864Y/0000868.000.html http://articles.adsabs.harvard.edu//full/1994Metic..29..864Y... (Man I am so far into the rabbit hole now) Looks like 15th century China had an event that probably had a number of casualties (though apparently modern researchers dispute the details). Wasn't aware of that. https://en.wikipedia.org/wiki/1490_Ch%27ing-yang_event https://en.wikipedia.org/wiki/1490_Ch%27ing-yang_event
- adrianN 10y ago
  I wouldn't bet on us noticing the meteor sufficiently early for an evacuation. We have mapped only a tiny portion of asteroids in our solar system and, iirc, the budget for that program keeps getting cut.
  - cryptoz 10y ago
    Luckily, there are new companies springing up to do work like this because it will be profitable some day. Planetary Resources is specifically looking for big rocks to do mining operations on, but is taking it into their own hands to map for unknown objects with Near Earth trajectories. That doesn't take away from how sad it is that our governments have cut the already-small budgets of important research like this. That's a crime, really. Edit: here's the startup pitch I added to our last YC application in the "other ideas" section (I wonder why it didn't get funded): ------- 4) Planetary defense network to protect from asteroid impact. Build small satellites to search for and redirect dangerous asteroids. Rather than last-minute warning systems or explosion/impact-based protection, it would work by slowly gravitationally changing dangerous asteroid orbits so that they will not hit Earth. Build it so that it’s gravitationally self-sufficient and can use captured asteroids to deflect incoming dangers. This is similar to the recent work at Planetary Resources in Seattle - while they prospect for minerals we would direct asteroid orbits. In February of 2016, NASA announced the creation of the Planetary Defense Office to coordinate these efforts globally. Now is the right time to start working on this. [1] http://www.scientificamerican.com/article/nasa-s-new-planetary-defense-office-gets-to-work-protecting-earth/ http://www.scientificamerican.com/article/nasa-s-new-planeta...
    - adrianN 10y ago
      But those efforts are mostly focused on the big asteroids that wipe out huge areas, right? Spotting an asteroid the size of a minivan or so is really hard, but if something of that size hits a city, thousands die.
      - dragonwriter 10y ago
        > Spotting an asteroid the size of a minivan or so is really hard Its really not; as I understand, our current technology is sufficient to find things much smaller than that at the distance of the inner edge of the Kuiper Belt. The problem, at any size, is that we scan very little of the sky, not that its hard to find objects of any size that would be dangerous.
    - Pica_soO 10y ago
      Not feasible as all governments of this planet suspect one another to use the captured meteors as ballistic weapons. Also planetary defense needs constant maintenance, so what if there is some crisis, and a prolonged downgrade of civilization?
      - cryptoz 10y ago
        Perhaps I haven't explained my idea very well. I'm imagining millions of small robotic spacecraft, self-constructed by self-mining asteroids that they have found on their own. The little asteroid spacecraft would roam the solar system on huge orbits and search for potential Earth impact-bound objects. If it finds something, over the course of hundreds of years, or thousands of years, the network of small asteroid spaceships could send a probe to the offending target and adjust its orbit so as not to impact. It could then use the offending targets to create new nodes in the system. Theoretically the defense network could last as long as the sun does. I do agree that the law of unintended consequences might mean that building such a system would instead ensure the destruction of the Earth rather than save it. But it's an idea.
        deftnerd 10y ago
  - throwaway_yy2Di 10y ago
    Which program are you referring to? LSST is fully funded. https://www.lsst.org/science/solar-system/potentially-hazardous-asteroids https://www.lsst.org/science/solar-system/potentially-hazard... https://en.wikipedia.org/wiki/Large_Synoptic_Survey_Telescope https://en.wikipedia.org/wiki/Large_Synoptic_Survey_Telescop...
- cryptoz 10y ago
  In 2013 in Russia, a meteor exploded over a city and injured thousands of people. https://en.wikipedia.org/wiki/Chelyabinsk_meteor https://en.wikipedia.org/wiki/Chelyabinsk_meteor Something extra interesting about this is the number of videos that recorded it due to the prevalence of car dash cams. This helped scientists quickly reconstruct what happened and is amazing footage to have of such a rare event.
  - kordless 10y ago
    > Russian authorities stated that 1,491 people, including 311 children, sought medical attention in Chelyabinsk Oblast within the first few days.
  - bpicolo 10y ago
    Yeah, I saw that. Looks like the shockwaves were the primary mode of injury, though I guess that will always be the primary mode of injury in a large explosion. No deaths that I could see, which is good. I remember seeing the dashcams back then
    - sandworm101 10y ago
      > Looks like the shockwaves were the primary mode of injury Not the shockwaves, but things damaged/knocked over by the waves. If you were standing in a field, the shockwave would do nothing to you. It was harmless. But if you are standing beside a poorly-designed glass building, pieces are going to fall off that building. This was Russia. I would expect that other countries, with different building practices, might suffer far fewer casualties.
      - bpicolo 10y ago
        Right, things damaged BY shockwaves, if we're being pedantic
      - benologist 10y ago
        Do countries legislate shockwave standards in buildings like they do cyclones/hurricanes/etc?
- dforrestwilson1 10y ago
  It wouldn't have to hit somewhere inhabited. If it landed in say, the Pacific Ocean you could see massive tidal waves on multiple population centers at once. Arguably a bigger threat than if something of equivalent size were to hit land. http://www.astronomynotes.com/solfluf/s5.htm http://www.astronomynotes.com/solfluf/s5.htm
  - escapologybb 10y ago
    Agreed, if something fairly small hit say Gran canaria then it's goodbye large parts of the UK and low-lying parts of Europe.
  - Jabbles 10y ago
    That article describes the effects of an event a million times more energetic that Tunguska. (6e7 vs 10-15 Megatons)
- internaut 10y ago
  > You have to wonder when a large piece of space rock will hit somewhere inhabited. That said, with 3% of earth's land being urban (3% of 29% of Earth), and reasonably infrequent falling rocks, it's really not that likely to happen in any given lifetime. Suppose the probability was close to 1 for this century instead of a long line of zeros with a 1 at the end. Why would that be the case? I'm not going to say it explicitly here but you should be able to figure it out. If you do, probably better not to elaborate. Merely reply with 'ZOG' or 'Oh Shit' and never get a good night's sleep ever again! ;-)
dmix 10y ago
This article sounds almost like a word-for-word reworking of the Wikipedia article, which I just read yesterday. I recommend reading that as it includes some great quotes from witnesses and a better overall structure: https://en.wikipedia.org/wiki/Tunguska_event https://en.wikipedia.org/wiki/Tunguska_event
sandworm101 10y ago
Bad news: It wasn't a very big rock. https://share.sandia.gov/news/resources/releases/2007/asteroid.html https://share.sandia.gov/news/resources/releases/2007/astero... Most descriptions speak of a single explosion, something comparable to a nuclear weapon. That isn't an appropriate model. It wasn't a single event at a fixed spot, nor was it a series of events. It was more of a continuous release of energy over a great distance. The rock exploded not at a particular altitude, but dissipated its energy into the atmosphere over a period of time/distance, a line rather than a point. Square-area/volume principals therefore do not apply directly. With that understanding it turns out it was probably a much smaller rock than previously though. The trees were not knocked over all at once. I think of it more as them being blown down in series as if by the wake of a passing boat, that boat being an exploding rock. So you cannot take the total damage area and calculate a single point for the explosion. Old model: http://www.sandia.gov/videos2007/2007-6514Pfire.hv1.2.mpg http://www.sandia.gov/videos2007/2007-6514Pfire.hv1.2.mpg New model: http://www.sandia.gov/videos2007/2007-6514Pfire.hv1.1.mpg http://www.sandia.gov/videos2007/2007-6514Pfire.hv1.1.mpg
- plusfour 10y ago
  The new model is a lot more badass than the old one.
alexholehouse 10y ago
So I've always had this (entirely crackpot) idea that the Tunguska Event is actually the place and time in space/history that you'd want to test the first time-travel device to. From a 'test system' design perspective: - You'd want it to be somewhere isolated to avoid casualties, especially if there was a radiation risk (which you wouldn't know). - You wouldn't want people to be able to analyze the immediate wreckage with any kind of high fidelity because there might be signatures of whatever you sent back (or however you sent it) that might change the course of history/technology. - You'd want there to be fairly detailed recordings (ideally photos), and for it to persist into modern history, not just be a weird anomaly of 'the past'. - You wouldn't want it be interpreted as some kind of military action. To be very clear, I don't actually believe this is what happened, but I quite like the idea...
- CaptSpify 10y ago
  I love stories based on these premises. It's so much fun to take a weird mysterious event, and put a conspiracy behind it. Why? I dunno. Some part of human nature, I guess. Also: https://www.comixology.com/Atomic-Robo-The-Shadow-From-Beyond-Time/digital-comic/197604 https://www.comixology.com/Atomic-Robo-The-Shadow-From-Beyon...
- powertower 10y ago
  That's actually one of the theories of crop circles... That they are signs being used to gauge how the time-line has been effected. http://www.cropcircleconnector.com/anasazi/fringe2015c.html http://www.cropcircleconnector.com/anasazi/fringe2015c.html
  - deleted 10y ago
    [deleted]
  - 467568985476 10y ago
    Wow! If "a group of remote viewers" concluded that, it must be true!
  - FreeFull 10y ago
    I'd say crop circles are made by bored people, using planks with rope tied to them, and markers so they know which way to flatten the crops.
lostlogin 10y ago
The theory that the lake which is a distance from the proposed centre of the blast is an impact crater may be born out by accounts from the time which describe multiple hits at varying distances.
xg15 10y ago
Summing up this article: When people were first investigating the Tunguska event, they believed it to be caused by an asteroid... They were probably right.
autokad 10y ago
I dont believe Lake Cheko is the impact site. its connected to a long river in both directions https://www.google.com/maps/place/60%C2%B055'00.0%22N+101%C2%B057'00.0%22E/@60.945417,101.839777,17648m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d60.9166667!4d101.95 https://www.google.com/maps/place/60%C2%B055'00.0%22N+101%C2...
mutagen 10y ago
Couple of papers from the Italian team that did bathymetry / seismics in Lake Cheko: http://sci-hub.cc/10.1007/s12210-015-0403-8 http://sci-hub.cc/10.1007/s12210-015-0403-8 https://www.researchgate.net/publication/229759371_Lake_Cheko_and_the_Tunguska_Event_Impact_or_non-impact https://www.researchgate.net/publication/229759371_Lake_Chek... Some argument against Cheko being an impact crater, referenced in the above work: http://www.univie.ac.at/geochemistry/koeberl/publikation_list/312-Lake-Cheko-not-impact-crater-Terra-Nova-2008.pdf http://www.univie.ac.at/geochemistry/koeberl/publikation_lis... Data from the Italian team that investigated Cheko: http://www-th.bo.infn.it/tunguska/ http://www-th.bo.infn.it/tunguska/
firebones 10y ago
What are the economics (and physics) of creating a football-field-sized (and proportionately-weighted) synthetic meteor and studying a controlled re-entry into some part of the ocean? Would that be a useful experiment in terms of learning how to deal with potential future threats, or too risky?
mirimir 10y ago
There's a great description of hypervelocity atmospheric impact in The Killing Star by Charles R. Pellegrino and George Zebrowski.
ivan_gammel 10y ago
In sci-fi book "Monday begins on Saturday" by Arkady and Boris Strugatsky there was cool, but rather unrealistic theory, according to which Tunguska event was a landing of an alien spaceship, which had reverse time arrow. They landed and then have gone to our past, finding themselves in the untouched ancient taiga, and leaving no traces in our future.

138 points by jackgavigan 10y ago

You have to wonder when a large piece of space rock will hit somewhere inhabited. That said, with 3% of earth's land being urban (3% of 29% of Earth), and reasonably infrequent falling rocks, it's really not that likely to happen in any given lifetime. I suspect we're keen enough these days to be able to predict and evacuate the right areas, though. This paper references another that suggests a "Tunguska Event" is a once in 200-300 year deal: http://articles.adsabs.harvard.edu//full/1994Metic..29..864Y/0000868.000.html http://articles.adsabs.harvard.edu//full/1994Metic..29..864Y... (Man I am so far into the rabbit hole now) Looks like 15th century China had an event that probably had a number of casualties (though apparently modern researchers dispute the details). Wasn't aware of that. https://en.wikipedia.org/wiki/1490_Ch%27ing-yang_event https://en.wikipedia.org/wiki/1490_Ch%27ing-yang_event

adrianN 10y ago
I wouldn't bet on us noticing the meteor sufficiently early for an evacuation. We have mapped only a tiny portion of asteroids in our solar system and, iirc, the budget for that program keeps getting cut.
- cryptoz 10y ago
  Luckily, there are new companies springing up to do work like this because it will be profitable some day. Planetary Resources is specifically looking for big rocks to do mining operations on, but is taking it into their own hands to map for unknown objects with Near Earth trajectories. That doesn't take away from how sad it is that our governments have cut the already-small budgets of important research like this. That's a crime, really. Edit: here's the startup pitch I added to our last YC application in the "other ideas" section (I wonder why it didn't get funded): ------- 4) Planetary defense network to protect from asteroid impact. Build small satellites to search for and redirect dangerous asteroids. Rather than last-minute warning systems or explosion/impact-based protection, it would work by slowly gravitationally changing dangerous asteroid orbits so that they will not hit Earth. Build it so that it’s gravitationally self-sufficient and can use captured asteroids to deflect incoming dangers. This is similar to the recent work at Planetary Resources in Seattle - while they prospect for minerals we would direct asteroid orbits. In February of 2016, NASA announced the creation of the Planetary Defense Office to coordinate these efforts globally. Now is the right time to start working on this. [1] http://www.scientificamerican.com/article/nasa-s-new-planetary-defense-office-gets-to-work-protecting-earth/ http://www.scientificamerican.com/article/nasa-s-new-planeta...
  - adrianN 10y ago
    But those efforts are mostly focused on the big asteroids that wipe out huge areas, right? Spotting an asteroid the size of a minivan or so is really hard, but if something of that size hits a city, thousands die.
    - dragonwriter 10y ago
      > Spotting an asteroid the size of a minivan or so is really hard Its really not; as I understand, our current technology is sufficient to find things much smaller than that at the distance of the inner edge of the Kuiper Belt. The problem, at any size, is that we scan very little of the sky, not that its hard to find objects of any size that would be dangerous.
  - Pica_soO 10y ago
    Not feasible as all governments of this planet suspect one another to use the captured meteors as ballistic weapons. Also planetary defense needs constant maintenance, so what if there is some crisis, and a prolonged downgrade of civilization?
    - cryptoz 10y ago
      Perhaps I haven't explained my idea very well. I'm imagining millions of small robotic spacecraft, self-constructed by self-mining asteroids that they have found on their own. The little asteroid spacecraft would roam the solar system on huge orbits and search for potential Earth impact-bound objects. If it finds something, over the course of hundreds of years, or thousands of years, the network of small asteroid spaceships could send a probe to the offending target and adjust its orbit so as not to impact. It could then use the offending targets to create new nodes in the system. Theoretically the defense network could last as long as the sun does. I do agree that the law of unintended consequences might mean that building such a system would instead ensure the destruction of the Earth rather than save it. But it's an idea.
      - deftnerd 10y ago
- throwaway_yy2Di 10y ago
  Which program are you referring to? LSST is fully funded. https://www.lsst.org/science/solar-system/potentially-hazardous-asteroids https://www.lsst.org/science/solar-system/potentially-hazard... https://en.wikipedia.org/wiki/Large_Synoptic_Survey_Telescope https://en.wikipedia.org/wiki/Large_Synoptic_Survey_Telescop...
cryptoz 10y ago
In 2013 in Russia, a meteor exploded over a city and injured thousands of people. https://en.wikipedia.org/wiki/Chelyabinsk_meteor https://en.wikipedia.org/wiki/Chelyabinsk_meteor Something extra interesting about this is the number of videos that recorded it due to the prevalence of car dash cams. This helped scientists quickly reconstruct what happened and is amazing footage to have of such a rare event.
- kordless 10y ago
  > Russian authorities stated that 1,491 people, including 311 children, sought medical attention in Chelyabinsk Oblast within the first few days.
- bpicolo 10y ago
  Yeah, I saw that. Looks like the shockwaves were the primary mode of injury, though I guess that will always be the primary mode of injury in a large explosion. No deaths that I could see, which is good. I remember seeing the dashcams back then
  - sandworm101 10y ago
    > Looks like the shockwaves were the primary mode of injury Not the shockwaves, but things damaged/knocked over by the waves. If you were standing in a field, the shockwave would do nothing to you. It was harmless. But if you are standing beside a poorly-designed glass building, pieces are going to fall off that building. This was Russia. I would expect that other countries, with different building practices, might suffer far fewer casualties.
    - bpicolo 10y ago
      Right, things damaged BY shockwaves, if we're being pedantic
    - benologist 10y ago
      Do countries legislate shockwave standards in buildings like they do cyclones/hurricanes/etc?
dforrestwilson1 10y ago
It wouldn't have to hit somewhere inhabited. If it landed in say, the Pacific Ocean you could see massive tidal waves on multiple population centers at once. Arguably a bigger threat than if something of equivalent size were to hit land. http://www.astronomynotes.com/solfluf/s5.htm http://www.astronomynotes.com/solfluf/s5.htm
- escapologybb 10y ago
  Agreed, if something fairly small hit say Gran canaria then it's goodbye large parts of the UK and low-lying parts of Europe.
- Jabbles 10y ago
  That article describes the effects of an event a million times more energetic that Tunguska. (6e7 vs 10-15 Megatons)
internaut 10y ago
> You have to wonder when a large piece of space rock will hit somewhere inhabited. That said, with 3% of earth's land being urban (3% of 29% of Earth), and reasonably infrequent falling rocks, it's really not that likely to happen in any given lifetime. Suppose the probability was close to 1 for this century instead of a long line of zeros with a 1 at the end. Why would that be the case? I'm not going to say it explicitly here but you should be able to figure it out. If you do, probably better not to elaborate. Merely reply with 'ZOG' or 'Oh Shit' and never get a good night's sleep ever again! ;-)

dmix 10y ago

This article sounds almost like a word-for-word reworking of the Wikipedia article, which I just read yesterday. I recommend reading that as it includes some great quotes from witnesses and a better overall structure: https://en.wikipedia.org/wiki/Tunguska_event https://en.wikipedia.org/wiki/Tunguska_event

sandworm101 10y ago

Bad news: It wasn't a very big rock. https://share.sandia.gov/news/resources/releases/2007/asteroid.html https://share.sandia.gov/news/resources/releases/2007/astero... Most descriptions speak of a single explosion, something comparable to a nuclear weapon. That isn't an appropriate model. It wasn't a single event at a fixed spot, nor was it a series of events. It was more of a continuous release of energy over a great distance. The rock exploded not at a particular altitude, but dissipated its energy into the atmosphere over a period of time/distance, a line rather than a point. Square-area/volume principals therefore do not apply directly. With that understanding it turns out it was probably a much smaller rock than previously though. The trees were not knocked over all at once. I think of it more as them being blown down in series as if by the wake of a passing boat, that boat being an exploding rock. So you cannot take the total damage area and calculate a single point for the explosion. Old model: http://www.sandia.gov/videos2007/2007-6514Pfire.hv1.2.mpg http://www.sandia.gov/videos2007/2007-6514Pfire.hv1.2.mpg New model: http://www.sandia.gov/videos2007/2007-6514Pfire.hv1.1.mpg http://www.sandia.gov/videos2007/2007-6514Pfire.hv1.1.mpg

plusfour 10y ago
The new model is a lot more badass than the old one.

alexholehouse 10y ago

So I've always had this (entirely crackpot) idea that the Tunguska Event is actually the place and time in space/history that you'd want to test the first time-travel device to. From a 'test system' design perspective: - You'd want it to be somewhere isolated to avoid casualties, especially if there was a radiation risk (which you wouldn't know). - You wouldn't want people to be able to analyze the immediate wreckage with any kind of high fidelity because there might be signatures of whatever you sent back (or however you sent it) that might change the course of history/technology. - You'd want there to be fairly detailed recordings (ideally photos), and for it to persist into modern history, not just be a weird anomaly of 'the past'. - You wouldn't want it be interpreted as some kind of military action. To be very clear, I don't actually believe this is what happened, but I quite like the idea...

CaptSpify 10y ago
I love stories based on these premises. It's so much fun to take a weird mysterious event, and put a conspiracy behind it. Why? I dunno. Some part of human nature, I guess. Also: https://www.comixology.com/Atomic-Robo-The-Shadow-From-Beyond-Time/digital-comic/197604 https://www.comixology.com/Atomic-Robo-The-Shadow-From-Beyon...
powertower 10y ago
That's actually one of the theories of crop circles... That they are signs being used to gauge how the time-line has been effected. http://www.cropcircleconnector.com/anasazi/fringe2015c.html http://www.cropcircleconnector.com/anasazi/fringe2015c.html
- deleted 10y ago
  [deleted]
- 467568985476 10y ago
  Wow! If "a group of remote viewers" concluded that, it must be true!
- FreeFull 10y ago
  I'd say crop circles are made by bored people, using planks with rope tied to them, and markers so they know which way to flatten the crops.

lostlogin 10y ago

The theory that the lake which is a distance from the proposed centre of the blast is an impact crater may be born out by accounts from the time which describe multiple hits at varying distances.

xg15 10y ago

Summing up this article: When people were first investigating the Tunguska event, they believed it to be caused by an asteroid... They were probably right.

autokad 10y ago

I dont believe Lake Cheko is the impact site. its connected to a long river in both directions https://www.google.com/maps/place/60%C2%B055'00.0%22N+101%C2%B057'00.0%22E/@60.945417,101.839777,17648m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d60.9166667!4d101.95 https://www.google.com/maps/place/60%C2%B055'00.0%22N+101%C2...

mutagen 10y ago

Couple of papers from the Italian team that did bathymetry / seismics in Lake Cheko: http://sci-hub.cc/10.1007/s12210-015-0403-8 http://sci-hub.cc/10.1007/s12210-015-0403-8 https://www.researchgate.net/publication/229759371_Lake_Cheko_and_the_Tunguska_Event_Impact_or_non-impact https://www.researchgate.net/publication/229759371_Lake_Chek... Some argument against Cheko being an impact crater, referenced in the above work: http://www.univie.ac.at/geochemistry/koeberl/publikation_list/312-Lake-Cheko-not-impact-crater-Terra-Nova-2008.pdf http://www.univie.ac.at/geochemistry/koeberl/publikation_lis... Data from the Italian team that investigated Cheko: http://www-th.bo.infn.it/tunguska/ http://www-th.bo.infn.it/tunguska/

firebones 10y ago

What are the economics (and physics) of creating a football-field-sized (and proportionately-weighted) synthetic meteor and studying a controlled re-entry into some part of the ocean? Would that be a useful experiment in terms of learning how to deal with potential future threats, or too risky?

mirimir 10y ago

There's a great description of hypervelocity atmospheric impact in The Killing Star by Charles R. Pellegrino and George Zebrowski.

ivan_gammel 10y ago

In sci-fi book "Monday begins on Saturday" by Arkady and Boris Strugatsky there was cool, but rather unrealistic theory, according to which Tunguska event was a landing of an alien spaceship, which had reverse time arrow. They landed and then have gone to our past, finding themselves in the untouched ancient taiga, and leaving no traces in our future.