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The Tunguska Event
- smoyer 11y agoI read an entire book about the Tunguska explosion when I was in junior high, but it's interesting that astronomers now think an event like this could happen every 300 years.
- krylon 11y agoOne interesting detail I found, I think, on Wikipedia, is that if the meteor had hit about four hours later, due to Earth's rotation, it would have roughly hit Saint Petersburg. If such events happen so frequently, we're pretty lucky so far. Given that much of Earth is covered in water, I could imagine a lot of these simply hit the ocean, but I don't know what would happen if it hit close to the coast.
- saiya-jin 11y agoa simple hit of ocean might be more devastating than hitting uninhabited parts of taiga. think about massive tsunami (at least that's what I would expect, depending on the impact force of course)
- masklinn 11y ago> think about massive tsunami (at least that's what I would expect, depending on the impact force of course) You'd need something way more powerful than the Tunguska event; ignoring that Tunguska was most likely an airburst (not an impact), its estimated yield was about twice the Castle Bravo yield which did generate relatively inconsequential waves compared to the rest of its issues. A "true" tsunami requires absolutely ridiculous amounts of water displacements, that doesn't happen with anything short of existential-risk impactors. Operation Hardtack confirmed that nuke-level energy didn't come close: there isn't enough displacement and that displacement is very temporary.
- gus_massa 11y agoSome similar analysis: "Mariana Trench Explosion" https://what-if.xkcd.com/15/ https://what-if.xkcd.com/15/ I think that if the asteroid is big enough to make a massive deadly tsunami, it will also create a very big mess if it hit the land.
- goldenkey 11y agowater is very dampening. tsunamis are from sustained force
- cr1895 11y agoIt's literally wet! You'll get dampened indeed. Tsunamis are generated by water displacement from e.g. underwater seismic activity or a massive landslide. Wind-driven waves or tides would be driven by sustained forces. Whether or not an asteroid can/has cause(d) a tsunami I don't know.
- raattgift 11y agoA sufficiently energetic meteor strike will cause a high enough amplitude wave to qualify as tsunamis (and which therefore would produce destructive effects onshore). Exact modelling is tricky, but that sort of thing appeals to some geophysicists. Funny headlines, serious research: http://news.ucsc.edu/2003/05/355.html http://news.ucsc.edu/2003/05/355.html http://www.livescience.com/49298-asteroids-causing-tsunamis.html http://www.livescience.com/49298-asteroids-causing-tsunamis....
- gaur 11y agoThe scaling with meteor size is impressive. A 100 m object will flatten some trees in Siberia. A 10 000 m object will kill 75% percent of all species on the planet (the KT event).
- elorant 11y agoThe problem with the latter is that it will cause a nuclear winter. So that 75% will not die instantly but in 2-3 years after the impact. Add an order of magnitude or even half of that and then you have an extinction level event. It could kill organisms even at microbe level.
- mikeash 11y agoKeep in mind that when taking about the diameter of a three dimensional object, the amount of stuff scales with the cube. The second one is a million times more meteor.
- mirimir 11y agoVelocity matters too. E ~ mv^2 after all. I'm reminded of Killing Star by Charles R. Pellegrino and George Zebrowski. Even without aggressive aliens, stuff falling toward the galaxy's central black hole may get ejected at relativistic velocity. Very unlikely. But we wouldn't see it until it was almost here.
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- mrfusion 11y agoI'm curious if we could mine in areas where large asteroids impacted and gets lots of minerals. Why do asteroid mining if we already have a few in the ground?
- krylon 11y agoI saw a documentary a couple of years back which looked into a correlation of former (likely/suspected) meteor impact sites and natural resources. It looked like lots of areas rich in interesting metals/minerals turned out to probably have been hit by meteors in the past. So in a way, we are doing that already (at least if that documentary was not totally bogus).
- stevedonovan 11y agoNew evidence for that: http://www.bbc.com/news/science-environment-14827624 http://www.bbc.com/news/science-environment-14827624
- creshal 11y agoThat's where meteoric iron comes from: https://en.wikipedia.org/wiki/Meteoric_iron https://en.wikipedia.org/wiki/Meteoric_iron Two problems with this: • There's not that many meteorites to go around. • Elements more volatile than metals (say, water) boil off and/or ablate off during atmospheric entry. If we want to have those, we'll need to mine them in space and shield them during re-entry. That is assuming we even want to bring those minerals back to Earth. Most proposals intend to use them in-situ to supply spaceborne operations – theoretically, launching the equipment necessary to strip-mine an asteroid is vastly cheaper than sending up the same amount of raw resources. If we can refine those resources efficiently enough in space, things like the ISS or Lunar bases become a lot cheaper. (Practice is, as always, a lot more complicated.)
- simonh 11y agoOne factor is that we can choose which of perhaps hundreds of thousands of asteroids are worth mining, while with past impacts we only get what we happen to have been given.
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- amelius 11y ago> Given a long enough time period, there is a nearly 100-percent chance an asteroid large enough to destroy most life on Earth will impact our planet. No worries. Since quantum mechanics dictates that, given enough time, anything can happen, we can also say that given a long enough time period, life will spontaneously reappear.
- grondilu 11y agoA more interesting question is : what kind of delay is worth worrying about? I mean, for instance it is known that life will remain possible on Earth for about 500 million years, after which the Sun will be too bright. We don't seriously worry about it, since so many things can happen in half a billion years that it does not make much sense to try to plan or predict anything in such a timeframe. Similarly, I personally don't worry about an impactor of 10 km diameter or so. Such an event is so rare that it's not likely to happen in several million years. To me that's still the kind of timeframe it does not make sense to worry about. I'm sure some people will disagree though. What is the limit? 10,000 years? 1,000? 100?
- adrianN 11y agoEventually you'll have to start worrying about very small but existential risks if you want any chance of preventing them. If the potential costs are as huge as they are with meteor impacts, I think the expected value of preparation is big enough.
- sillysaurus3 11y agoThe way to do this is to make it profitable to worry about it. Some say that certain asteroids are worth trillions. While they're probably not worth quite that much, they're a pretty penny. Investors might be interested in a company designed to capture and harvest asteroids. It will probably take a few centuries before that's a possibility, but it's interesting that it's probably just a matter of time before it doesn't sound so crazy.
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- pmoriarty 11y agoHere's a fantastic simulation of a much bigger impact: https://www.youtube.com/watch?v=zc4HL_-VT2Y
- dr_zoidberg 11y agoA few questions/comments: * What is the "4 billion years ago impact" that is refered in the video? At first I thought it was the Theia impact, but the sizes and speeds don't quite match, and the simulation doesn't result in a second moon. * It also mentions that it has happened 6 times. The only impact large enough I can remember of the top of my head that sort of matches that scale would be the canadian impact basin. A quick search on wikipedia tossed me to this list [0] but everything there seems to be on a different scale than what's described in the video. Are those impacts mentioned in the full program? * It was recently reported that an expedition drilling in a part of the ocean where the crust is thin had found microbes near the magma, but I can't find any link. Given that it has been theorized even Venus may hold life in it's upper atmosphere [1], my guess would bethat, life is far more resilient than we imagine it to be. [0] https://en.wikipedia.org/wiki/List_of_impact_craters_on_Earth https://en.wikipedia.org/wiki/List_of_impact_craters_on_Eart... [1] http://web.archive.org/web/20110807004311/http://gltrs.grc.nasa.gov/reports/2003/TM-2003-212310.pdf http://web.archive.org/web/20110807004311/http://gltrs.grc.n...
- bsenftner 11y agoA fun science fiction read is "Singularity" by Bill DeSmedt; the premise is the Tunguska event being a mini-black hole - and it's caught inside the earth, eating it from the inside out.
- norea-armozel 11y agoI love that book. I listened to his podiobook version of it a few years ago. It still seems scary despite how very unlikely the scenario is to be true.
- NoMoreNicksLeft 11y agoDavid Brin did that too. Then an earth goddess showed up, some white guilt about overpopulation and coke can pull tabs. Is the DeSmedt book better?
- norea-armozel 11y agoI would argue it's much better. I don't want to give away too much of the story but it has lots of questions about physics, politics, and alternate history. It's quite a good read.
- sun_of_deep 11y ago> With this in mind, we can view our future with some certainty. Something big is going to smash into us, sooner or later, and probably sooner. I started reading Cosmos by Carl Sagan a week ago and he discusses the Tunguska event for several pages. It's an amazing book that I wish I had studied long ago. Had I not read that book, this statement would have instilled an impending sense of doom into me, which does nothing but demoralize me. Now that I've read that book, I can now tell with certainty that this prophecy is utter crap. As this article mentions, the asteroids are being tracked, so, we most likely will know it before hand. OTOH, here's an article from science alert http://www.sciencealert.com/next-month-an-asteroid-will-pass-so-close-to-earth-that-we-could-see-it-in-the-sky http://www.sciencealert.com/next-month-an-asteroid-will-pass... > Before you freak out, there's no chance that the asteroid is going to smash into us. The space agency is still determining its exact trajectory, but at the closest estimate, it'll be 18,000 km (11,000 miles) away as it passes us by - which would make it easily viewable with the help of a telescope. To put that into perspective, that's roughly one-twentieth the distance from Earth to the Moon. Alternatively, the asteroid could travel further afield, and pass us at a distance of around 14 million km (9 million miles). > The reason for the big difference in these two estimates is that NASA only discovered this asteroid three years ago - hence the very-catchy name, asteroid 2013 TX68 - and haven't had much time to observe it just yet.
- JoeAltmaier 11y agoMy favorite conspiracy theory on Tunguska: http://www.reformation.org/tesla-and-tunguska.html http://www.reformation.org/tesla-and-tunguska.html
- alexandre_m 11y agoThe Tunguska+Tesla event is quite fascinating (the whole life of Tesla is actually). People love to make up a lot of theories and conspiracies, it's nothing new. What is particularly worrisome is that Tesla was a very brillant man and that he believed himself to have caused this. From the information that we have, it wasn't a marketing stunt by his entourage. The guy himself was working on this particle-beam for some time and claimed to have triggered it that night. He tried to sell the technology for more almost 3 decades. Was this made up, was this a coincidence, or did it actually happen? It's been over 100 years and no one is certain.
- greglindahl 11y agoExtraordinary claims require extraordinary proof. "No one is certain" is not the right way to approach the possibility that Tesla actually caused Tunguska. edit: clarified what "this" means
- JoeAltmaier 11y agoIts reasonable to speculate on whether Tesla himself believed he'd caused the incident.
- alexandre_m 11y agoI don't think it's plausible that Tesla is responsable for it, but we can raise some questions surrounding the event. Apparently there's still no scientific consensus (is that even possible?) on the Tunguska explosion and NASA seems to acknowledges that. Taken from: http://science.nasa.gov/science-news/science-at-nasa/2008/30jun_tunguska/ http://science.nasa.gov/science-news/science-at-nasa/2008/30... "A century later some still debate the cause and come up with different scenarios that could have caused the explosion," said Yeomans" No remains of the asteroid, no impact crater and the claims from Tesla together is what is fascinating to me.
- gmisra 11y agoThere is a great twitter feed, @AsteroidMisses, that tweets out based off a NASA monitoring dataset. Browsing it provides some perspective on just how many asteroids are whizzing around the Earth all the time. https://twitter.com/asteroidmisses https://twitter.com/asteroidmisses