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May 3, 2014 9:22 PM Subscribe
I consider anything that passes closer to us than the moon with only days of warning to be at the very least a sobering reminder. The Chelyabinsk meteoroid was approximately the size of a substantial barn and we had zero warning of that whatsoever.
posted by dhartung at 9:57 PM on May 3, 2014 [16 favorites]
posted by dhartung at 9:57 PM on May 3, 2014 [16 favorites]
Some perspective may be gained by following lowflyingrocks on Twitter. The last ten passes average out at 10 million km, or about thirty times the average distance to the Moon. I basically give a wry smile at the ones over 1 million km, but that's still outside the Moon's orbit nearly thrice. When I see one that's in lunar orbit range I raise an eyebrow. But when I see one this close, I gulp. It isn't about thinking "gosh, this one could have hit us with a mere many-hundred-thousands of km deviation!", it's about "hoo boy, what about the next one, or the one after that?"
Basically, the prevailing conventional wisdom for a long time was that this was such a rare event we didn't need to worry about it. But now we know we can have a substantial bolide exploding over populated areas maybe once in a hundred years (Tunguska, Chelyabinsk), or maybe even more often since more of the world is a "populated area". Then there's the tsunami risk associated with an oceanic impact. Still, clearly another bolide with the destructive potential of Chelyabinsk in another area could have been seriously disastrous.
Do I really think this is going to happen? No, geologic evidence is still strongly indicative of this being a fairly rare event. But we're at the point now where we have the means to do something, and I really, really hope we develop and implement a practical application of our capability, because we're pretty smart and not doing so would be pretty dumb. I'm also of the opinion that a lot of options for us are not particularly expensive in comparison to the potential risk to property and life.
posted by dhartung at 10:12 PM on May 3, 2014 [15 favorites]
Basically, the prevailing conventional wisdom for a long time was that this was such a rare event we didn't need to worry about it. But now we know we can have a substantial bolide exploding over populated areas maybe once in a hundred years (Tunguska, Chelyabinsk), or maybe even more often since more of the world is a "populated area". Then there's the tsunami risk associated with an oceanic impact. Still, clearly another bolide with the destructive potential of Chelyabinsk in another area could have been seriously disastrous.
Do I really think this is going to happen? No, geologic evidence is still strongly indicative of this being a fairly rare event. But we're at the point now where we have the means to do something, and I really, really hope we develop and implement a practical application of our capability, because we're pretty smart and not doing so would be pretty dumb. I'm also of the opinion that a lot of options for us are not particularly expensive in comparison to the potential risk to property and life.
posted by dhartung at 10:12 PM on May 3, 2014 [15 favorites]
but we're at the point now where we have the means to do something
What could we have done in such little time? I mean Wednesday April 28 was only ...
huh.
April 28 was a Monday.
So I have no idea how much warning we actually had. 3 or 5 days I guess?
posted by aubilenon at 10:30 PM on May 3, 2014 [1 favorite]
What could we have done in such little time? I mean Wednesday April 28 was only ...
huh.
April 28 was a Monday.
So I have no idea how much warning we actually had. 3 or 5 days I guess?
posted by aubilenon at 10:30 PM on May 3, 2014 [1 favorite]
I almost got hit by a bus today. Well, it was the size of a bus.
posted by five fresh fish at 10:49 PM on May 3, 2014 [5 favorites]
posted by five fresh fish at 10:49 PM on May 3, 2014 [5 favorites]
April 28 was a Monday.That's probably just that someone looked for the day of the week of the 28th on a calendar, but accidentally looked in May.
I assume that "we have the means to do something" means something like "we have the means to set up a significantly better early detection system than we have, and the means to set up a system to deal with threatening asteroids if detected early enough", not "the other day we had the means to deal with this threatening asteroid".but we're at the point now where we have the means to do somethingWhat could we have done in such little time?
posted by Flunkie at 11:01 PM on May 3, 2014
I know, and Bruce Willis is probably committed to a project. Oh, darn!
Seriously, and I don't want to belabor this needlessly, but I mean as a civilization we have:
* observational capability (for very distant and early detection)
* computing capability (for very accurate prediction of orbital elements)
* space launch capability (for at least getting something up where it can do some good)
* interception capability (comet chasing craft have proven it is fairly possible, and Rosetta will rendezvous with a comet later this month)
* landing capability (to be demonstrated by Rosetta's attached lander, Philae, later this year)
* presumably, diversion capability (given enough time there are many options, which we will need to develop and specialize, but clearly within our civilizational range of capability)
Just within the last month, the B612 Foundation released video derived from the satellites that watch Earth for nuclear explosions, to enforce the test ban treaties, showing that there have probably been 26 significant asteroid impacts on Earth (at least its atmosphere) in the thirteen years from 2000 to 2012. (That's two a year on average.) Even though generally these had little discernible effect on humans, the frequency is far higher than had previously been assumed. As such B612 is privately funding the Sentinel mission which by design will attempt to catalog 90% of the Earth-orbit-crossing asteroids.
NASA has also been studying an asteroid intercept mission and has even floated an asteroid capture mission (as yet unfunded), in part as a first step toward Mars exploration.
Generally there has been a lot of public support for human spaceflight and science just as a general proposition, largely for its inspirational effect, but here we are faced with a practical mission where we can put all this we've learned the last half century into accomplishing something that is really needed.
posted by dhartung at 11:02 PM on May 3, 2014 [20 favorites]
Seriously, and I don't want to belabor this needlessly, but I mean as a civilization we have:
* observational capability (for very distant and early detection)
* computing capability (for very accurate prediction of orbital elements)
* space launch capability (for at least getting something up where it can do some good)
* interception capability (comet chasing craft have proven it is fairly possible, and Rosetta will rendezvous with a comet later this month)
* landing capability (to be demonstrated by Rosetta's attached lander, Philae, later this year)
* presumably, diversion capability (given enough time there are many options, which we will need to develop and specialize, but clearly within our civilizational range of capability)
Just within the last month, the B612 Foundation released video derived from the satellites that watch Earth for nuclear explosions, to enforce the test ban treaties, showing that there have probably been 26 significant asteroid impacts on Earth (at least its atmosphere) in the thirteen years from 2000 to 2012. (That's two a year on average.) Even though generally these had little discernible effect on humans, the frequency is far higher than had previously been assumed. As such B612 is privately funding the Sentinel mission which by design will attempt to catalog 90% of the Earth-orbit-crossing asteroids.
NASA has also been studying an asteroid intercept mission and has even floated an asteroid capture mission (as yet unfunded), in part as a first step toward Mars exploration.
Generally there has been a lot of public support for human spaceflight and science just as a general proposition, largely for its inspirational effect, but here we are faced with a practical mission where we can put all this we've learned the last half century into accomplishing something that is really needed.
posted by dhartung at 11:02 PM on May 3, 2014 [20 favorites]
I consider anything that passes closer than the orbit of the moon to be the cosmic equivalent of being shot at but having the bullet pass through some loose clothing while missing your flesh. Sure, you didn't get shot but come on.
posted by ricochet biscuit at 11:16 PM on May 3, 2014 [11 favorites]
posted by ricochet biscuit at 11:16 PM on May 3, 2014 [11 favorites]
It's more remarkable that we spotted a rock this small rather than that it came so close to the Earth -- things as big as this hit the Earth about once every 5 years (according to a calculator linked from wikipedia, at least). Indeed, lots of smaller rocks hit the Earth every day (we see them as meteors).
If it had hit the Earth, it would have caused minimal damage, exploding at high altitude. Start worrying when you hear about asteroids larger than 100 meters or so, though even then, odds are any impactor misses inhabited areas.
posted by janewman at 11:16 PM on May 3, 2014 [3 favorites]
If it had hit the Earth, it would have caused minimal damage, exploding at high altitude. Start worrying when you hear about asteroids larger than 100 meters or so, though even then, odds are any impactor misses inhabited areas.
posted by janewman at 11:16 PM on May 3, 2014 [3 favorites]
Ricochet biscuit: given the cross-sectional area of the Earth vs. the Moon's orbit, that's more like having a bullet pass within 100 feet of you than having a bullet pass through your clothes (or more realistically, similar odds to surviving a bullet passing somewhere within 1 km of you, if the bullets are traveling parallel to the ground in your general direction rather than you sitting in the bullseye of a target they are flying towards).
Or, in this case, if we consider a bullet to be equivalent to a rock that could take out a city, given the mass of this asteroid it's more like a snowflake passing somewhere within 100 feet (for a 2D case)/1 km (1D) of you. I'd take that bet. If travelling as fast as a bullet, that snowflake would hit you with about as much energy as a 20 gram (0.7 ounce) weight that had fallen a meter. This asteroid would have a similarly small amount of impact on the Earth.
posted by janewman at 11:31 PM on May 3, 2014 [1 favorite]
Or, in this case, if we consider a bullet to be equivalent to a rock that could take out a city, given the mass of this asteroid it's more like a snowflake passing somewhere within 100 feet (for a 2D case)/1 km (1D) of you. I'd take that bet. If travelling as fast as a bullet, that snowflake would hit you with about as much energy as a 20 gram (0.7 ounce) weight that had fallen a meter. This asteroid would have a similarly small amount of impact on the Earth.
posted by janewman at 11:31 PM on May 3, 2014 [1 favorite]
a sobering reminder.
You deal with it your way, I'll deal with it mine.
posted by ODiV at 11:32 PM on May 3, 2014 [37 favorites]
You deal with it your way, I'll deal with it mine.
posted by ODiV at 11:32 PM on May 3, 2014 [37 favorites]
dhartung: People tend to propose doing asteroid searches from space -- partially because NASA has been given responsibility for finding potential killer rocks -- but the Large Synoptic Survey Telescope now under construction could accomplish the same thing at much lower cost (something like $50 million to run the telescope 1-2 years longer than planned). Even the cheapest infrared missions are much more expensive than that.
posted by janewman at 11:41 PM on May 3, 2014
posted by janewman at 11:41 PM on May 3, 2014
Ah, Sentinel's supposed to cost $450M (according to an article cited on wikipedia). You could build a second LSST for that much money. . .
posted by janewman at 11:43 PM on May 3, 2014
posted by janewman at 11:43 PM on May 3, 2014
This Ancient Asteroid Strike Was More Insane Than We Realized
posted by homunculus at 12:05 AM on May 4, 2014 [7 favorites]
posted by homunculus at 12:05 AM on May 4, 2014 [7 favorites]
The Chelyabinsk meteoroid was approximately the size of a substantial barn and we had zero warning of that whatsoever.
I'm sorry, I know we were discussing the destruction of everything, but I just love "substantial barn" as a unit of measurement.
That's area, not mass, right? With or without cows?
posted by univac at 1:07 AM on May 4, 2014 [10 favorites]
I'm sorry, I know we were discussing the destruction of everything, but I just love "substantial barn" as a unit of measurement.
That's area, not mass, right? With or without cows?
posted by univac at 1:07 AM on May 4, 2014 [10 favorites]
Janewman, you're looking with too forgiving a lens. Given the cross-sectional area of the earth's orbit vs the orbit of everything else in the universe, suddenly the so-called bullet within 100 feet of you takes on new significance ie holy crap, bullets!
This asteroid is not the problem. It is asteroids, per se.
Think of it like being a serious criminal and chronically committing a signature serious crime. You could get away with it your whole life, hundreds, thousands, tens of thousands of times even. But the fact is no matter how many times you get away with it, you only have to be caught once.
Only in this case, "getting caught once" means having your asteroid getting hit with an asteroid big enough to destroy a city ie 20-40 meters in diameter.
As for taking those odds, judging from the appearance of the moon, if those odds were offered to me I wouldn't. However, we don't really have the choice, do we?
I mean, it was just a hundred years ago when something big enough to destroy a city did hit the earth.
We can have a near infinite series of "near-misses" but just a single hit to end the game. Just ask the dinosaurs. You know, if there were any alive to ask.
Like the tshirt says, "Asteroids. Nature's way of asking, "So, how's that space program coming along?""
posted by Mike Mongo at 1:29 AM on May 4, 2014 [6 favorites]
This asteroid is not the problem. It is asteroids, per se.
Think of it like being a serious criminal and chronically committing a signature serious crime. You could get away with it your whole life, hundreds, thousands, tens of thousands of times even. But the fact is no matter how many times you get away with it, you only have to be caught once.
Only in this case, "getting caught once" means having your asteroid getting hit with an asteroid big enough to destroy a city ie 20-40 meters in diameter.
As for taking those odds, judging from the appearance of the moon, if those odds were offered to me I wouldn't. However, we don't really have the choice, do we?
I mean, it was just a hundred years ago when something big enough to destroy a city did hit the earth.
We can have a near infinite series of "near-misses" but just a single hit to end the game. Just ask the dinosaurs. You know, if there were any alive to ask.
Like the tshirt says, "Asteroids. Nature's way of asking, "So, how's that space program coming along?""
posted by Mike Mongo at 1:29 AM on May 4, 2014 [6 favorites]
univac, in all seriousness A barn (symbol b) is a unit of area...
So named because it's huge (as in, "couldn't hit the side of a barn"), at least in particle physics terms.
(As an aside, I just learned that Wikipedia has a List of humorous units of measurement, because of course it does)
posted by metaBugs at 1:36 AM on May 4, 2014 [4 favorites]
So named because it's huge (as in, "couldn't hit the side of a barn"), at least in particle physics terms.
(As an aside, I just learned that Wikipedia has a List of humorous units of measurement, because of course it does)
posted by metaBugs at 1:36 AM on May 4, 2014 [4 favorites]
*Gives Asteroid 2014 HL129 the middle finger*
Yeah, you better run asshole!
Punk ass asteriod.
posted by Brandon Blatcher at 5:30 AM on May 4, 2014 [3 favorites]
Yeah, you better run asshole!
Punk ass asteriod.
posted by Brandon Blatcher at 5:30 AM on May 4, 2014 [3 favorites]
Relax everyone. I'm on it. I've logged many hours in this and am confident I can take down even bus sized asteroids with enough quarters.
posted by birdherder at 7:02 AM on May 4, 2014 [2 favorites]
posted by birdherder at 7:02 AM on May 4, 2014 [2 favorites]
Mike Mongo: asteroids big enough to destroy a city (~140 m and up) pass within the radius of the Moon's orbit about once every 200 years. Actual impacts with asteroids that size occur less than once every 10,000 years. We absolutely want to find and stop them, so I guess I should be happy that stories like this keep the potential for disaster on peoples' minds, but there's a large tendency for "near"-misses to be overhyped. Space as a whole is very empty but the Solar System is much denser on average (as the impact history on the surface of the Moon demonstrates); there are little rocks everywhere (estimates are that something like 100 tons of stuff hits the Earth per day).
Note that the Tunguska event was an airburst from a cometary fragment, not an impact by a stony asteroid. The effect on the ground is less (though still striking, of course). We have only a negligible chance of finding cometary impactors long before they hit us, so they aren't really a part of the conversation of what to do in the near term.
posted by janewman at 10:55 AM on May 4, 2014
Note that the Tunguska event was an airburst from a cometary fragment, not an impact by a stony asteroid. The effect on the ground is less (though still striking, of course). We have only a negligible chance of finding cometary impactors long before they hit us, so they aren't really a part of the conversation of what to do in the near term.
posted by janewman at 10:55 AM on May 4, 2014
Asteroid flybys are nature's way of asking us how the space program is coming along.
Less flippantly, I am continuously dismayed and angered at how cavalierly we as a species treat stuff like this. For vastly less money than was squandered on Bush's adventurism in Iraq and Afghanistan we could have built a decent skywatch and developed diversion capability.
But, despite near misses, despite the evidence of cataclysmic impacts in the past, and despite the fragility of our just in time distribution infrastructure and the fact that most of us live in places where we'd starve if food delivery stopped for even two or three weeks, the USA is joined by the rest of the world in giving a collective shrug and "meh" when the proposals to actually **DO** something about the problem come around. We could solve the problem for less than 10% of the military's budget for just one year and the benefits would be enormous.
Even a small asteroid impact could utterly trash our civilization. As a species we'd certainly live through a small impact, but we'd suffer a massive setback in technology and society. A larger impact could well wipe us out as a species. And this problem is simply ignored.
A lousy airplane being flown into a building, an event causing only a few kilodeaths, is treated as world changing and an excuse to squander trillions invading third world shithole nations. Bush and Cheney famously claimed that if there was even a 1% chance that a terrorist attack might happen they would treat it as if the odds were 100% and respond with no reservations in either money spent or military resources deployed.
But the possibility for megadeaths, even gigadeaths, and the total devastation of our civilization and all technology more advanced than stone knives and bear skins is utterly ignored at best and at worst those worrying are treated as if they were mentally ill or suffering from reading too much science fiction.
posted by sotonohito at 11:16 AM on May 4, 2014 [4 favorites]
Less flippantly, I am continuously dismayed and angered at how cavalierly we as a species treat stuff like this. For vastly less money than was squandered on Bush's adventurism in Iraq and Afghanistan we could have built a decent skywatch and developed diversion capability.
But, despite near misses, despite the evidence of cataclysmic impacts in the past, and despite the fragility of our just in time distribution infrastructure and the fact that most of us live in places where we'd starve if food delivery stopped for even two or three weeks, the USA is joined by the rest of the world in giving a collective shrug and "meh" when the proposals to actually **DO** something about the problem come around. We could solve the problem for less than 10% of the military's budget for just one year and the benefits would be enormous.
Even a small asteroid impact could utterly trash our civilization. As a species we'd certainly live through a small impact, but we'd suffer a massive setback in technology and society. A larger impact could well wipe us out as a species. And this problem is simply ignored.
A lousy airplane being flown into a building, an event causing only a few kilodeaths, is treated as world changing and an excuse to squander trillions invading third world shithole nations. Bush and Cheney famously claimed that if there was even a 1% chance that a terrorist attack might happen they would treat it as if the odds were 100% and respond with no reservations in either money spent or military resources deployed.
But the possibility for megadeaths, even gigadeaths, and the total devastation of our civilization and all technology more advanced than stone knives and bear skins is utterly ignored at best and at worst those worrying are treated as if they were mentally ill or suffering from reading too much science fiction.
posted by sotonohito at 11:16 AM on May 4, 2014 [4 favorites]
Sotonohito: I hope I'm not coming across as saying we shouldn't worry about giant impacts and do whatever we can to remove that risk. We absolutely should (though I don't see reason to spend half a billion to find the things when you can do it for a tenth the cost. NASA should work on ideas for missions to stop these things, but finding them can most readily be done from the ground).
My concern is that if the press keeps overhyping little rocks that don't come anywhere near close enough to hit the Earth, you quickly hit the 'boy who cried wolf' problem and people tune this all out. Our technology for finding these things is getting better and better, so reports like this could become more and more common. . . and quickly fade into background noise.
It's important to keep in mind, regardless, that climate change is far, far more likely to cause disruptions in the next century than a giant impact. That's the way probability works. Mass extinctions due to impacts happen at a rate much closer to once per hundred million years than once per human lifetime. We want to address both risks, but the high-probability one deserves more attention, even if the solutions are generally less exciting than stopping a killer asteroid.
posted by janewman at 11:33 AM on May 4, 2014
My concern is that if the press keeps overhyping little rocks that don't come anywhere near close enough to hit the Earth, you quickly hit the 'boy who cried wolf' problem and people tune this all out. Our technology for finding these things is getting better and better, so reports like this could become more and more common. . . and quickly fade into background noise.
It's important to keep in mind, regardless, that climate change is far, far more likely to cause disruptions in the next century than a giant impact. That's the way probability works. Mass extinctions due to impacts happen at a rate much closer to once per hundred million years than once per human lifetime. We want to address both risks, but the high-probability one deserves more attention, even if the solutions are generally less exciting than stopping a killer asteroid.
posted by janewman at 11:33 AM on May 4, 2014
but finding them can most readily be done from the ground
AFAIk that isn't even wrong. There's a reason why Hubble/etc are in space: no atmospheric interference, less radio interference, etc etc etc.
posted by feckless fecal fear mongering at 11:39 AM on May 4, 2014
AFAIk that isn't even wrong. There's a reason why Hubble/etc are in space: no atmospheric interference, less radio interference, etc etc etc.
posted by feckless fecal fear mongering at 11:39 AM on May 4, 2014
Being able to predict an asteroid hit still wouldn't provide enough motivation for a diversion effort. The governments of the world would want to know which country/countries were in the direct line of fire before making their decision.
posted by ceribus peribus at 12:04 PM on May 4, 2014
posted by ceribus peribus at 12:04 PM on May 4, 2014
Note that the Tunguska event was an airburst from a cometary fragment, not an impact by a stony asteroid.
This isn't known for sure (then again, I apparently don't know the difference) and in any case it caused 80 million trees to fall in an area of 800 square miles, and was only a little over a hundred years ago.
Asteroid flybys are nature's way of asking us how the space program is coming along.
Hah! This was mentioned before. But this isn't crying wolf. It is more like howling wolves. Each one we hear reminds us of the danger that can strike us at any time.
posted by eye of newt at 12:13 PM on May 4, 2014 [1 favorite]
This isn't known for sure (then again, I apparently don't know the difference) and in any case it caused 80 million trees to fall in an area of 800 square miles, and was only a little over a hundred years ago.
Asteroid flybys are nature's way of asking us how the space program is coming along.
Hah! This was mentioned before. But this isn't crying wolf. It is more like howling wolves. Each one we hear reminds us of the danger that can strike us at any time.
posted by eye of newt at 12:13 PM on May 4, 2014 [1 favorite]
@janewman: I agree about boy who cried wolf, but I'm not sure we're even at that point. As far as I can tell the majority of humans seem to view anything happening outside the atmosphere as purely the realm of fantasy, something that nerds into science fiction might bother talking about but not anything any mature and sensible human should bother even thinking about much less doing anything about.
As for spotting, you appear to be the expert so I'll certainly take your word for the equipment necessary. For the record, when I said "skywatch" I wasn't referring to any particular form of telescope or other equipment but using it as a generic term to mean whatever technology works out best for the job. Whether that's space based telescopes or terrestrial telescopes, or something else altogether (I heard someone talking about the possibility of using nukes tuned to emit in radar frequencies as flashbulbs for a 3D Doppler image of our solar system, dunno if that could even remotely work in the real world but it sounded interesting). Nor was I particularly advocating spending even a trillion dollars on a skywatch program, I'm sure it could be done for much less. I was merely pointing out that we happily spent upwards of five trillion on Bush's adventurism in the middle east and the impetus for that was a mere handful of kilodeaths.
I think we're in agreement that we need a better skywatch than we have now if rocks can keep popping up with little or no notice. Heck, even one as small as this most recent flyby could be regionally devastating if it hit New York, or Delhi, or Berlin, or [insert your favorite city here] at a decent speed.
And yet the overwhelming majority of the human population treats the entire thing as a joke.
Certainly I agree that global climate change is a very big deal and one we need to spend a lot of time and money working on fixing. But that's going to require whole orders of new technology and social realignment to resolve. We can fix the problem of rocks from space killing us all using off the shelf technology and for only a tiny budget. But no one seems to give a shit.
posted by sotonohito at 12:32 PM on May 4, 2014
As for spotting, you appear to be the expert so I'll certainly take your word for the equipment necessary. For the record, when I said "skywatch" I wasn't referring to any particular form of telescope or other equipment but using it as a generic term to mean whatever technology works out best for the job. Whether that's space based telescopes or terrestrial telescopes, or something else altogether (I heard someone talking about the possibility of using nukes tuned to emit in radar frequencies as flashbulbs for a 3D Doppler image of our solar system, dunno if that could even remotely work in the real world but it sounded interesting). Nor was I particularly advocating spending even a trillion dollars on a skywatch program, I'm sure it could be done for much less. I was merely pointing out that we happily spent upwards of five trillion on Bush's adventurism in the middle east and the impetus for that was a mere handful of kilodeaths.
I think we're in agreement that we need a better skywatch than we have now if rocks can keep popping up with little or no notice. Heck, even one as small as this most recent flyby could be regionally devastating if it hit New York, or Delhi, or Berlin, or [insert your favorite city here] at a decent speed.
And yet the overwhelming majority of the human population treats the entire thing as a joke.
Certainly I agree that global climate change is a very big deal and one we need to spend a lot of time and money working on fixing. But that's going to require whole orders of new technology and social realignment to resolve. We can fix the problem of rocks from space killing us all using off the shelf technology and for only a tiny budget. But no one seems to give a shit.
posted by sotonohito at 12:32 PM on May 4, 2014
sotonohito: Yes, we're very much in agreement that better efforts are needed to find killer asteroids (and to prepare to stop them).
This rock couldn't actually hit New York, or Delhi, or any other city though; it would explode in the upper atmosphere (100,000 feet up) with minimal impact.
feckless: Trust me, I know well why we put telescopes in space (amongst other things, I'm part of the CANDELS team that has obtained the largest allocation of Hubble time ever given to a single project, lead an effort to use data from the WISE satellite to identify distant, massive galaxies for the eBOSS and DESI surveys, and have been making minor contributions to studies of requirements for WFIRST-AFTA). Radio interference isn't the issue for any existing projects (yes, people have talked about putting radio telescopes on the dark side of the moon, but that's mostly because NASA was looking for justifications for new moon missions).
The reason Sentinel would be in space is because the atmosphere is bright at infrared wavelengths, and dark asteroids will be relatively bright in the IR compared to the optical so it's a pretty good way to search. LSST goes as far into the IR as you can go efficiently from the ground, and combines a large diameter telescope (8m) with an extremely wide field of view design. This allows sensitive searches for asteroids (amongst many, many other things -- the original goal of the telescope was for cosmology). Sentinel can use a smaller (0.5m) diameter telescope to accomplish the same goal thanks to being in space, allowing it to observe efficiently at the 'easier' longer wavelengths; but it's still outrageously expensive compared to a ground-based search.
tl;dr: the asteroids are fainter at the wavelengths LSST will use, but LSST is a much larger-diameter telescope and thus can see fainter things in the same amount of observing time.
Hubble is in space for a very different reason: blurring by the atmosphere (for reasons related to why stars twinkle) causes the amount of detail you can see for distant objects to be limited from the ground without special technologies that currently only work in the IR, but in space that's not an issue. Hubble has a modest infrared capability (thanks to the WFC3 camera added in its latest repair mission), but that's not why it was designed (in fact, it has bigger advantages over the ground in the ultraviolet -- thankfully for us, the atmosphere absorbs UV -- than in the IR). Hubble's field of view is tiny, though; it's irrelevant for asteroid searches.
posted by janewman at 3:02 PM on May 4, 2014 [6 favorites]
This rock couldn't actually hit New York, or Delhi, or any other city though; it would explode in the upper atmosphere (100,000 feet up) with minimal impact.
feckless: Trust me, I know well why we put telescopes in space (amongst other things, I'm part of the CANDELS team that has obtained the largest allocation of Hubble time ever given to a single project, lead an effort to use data from the WISE satellite to identify distant, massive galaxies for the eBOSS and DESI surveys, and have been making minor contributions to studies of requirements for WFIRST-AFTA). Radio interference isn't the issue for any existing projects (yes, people have talked about putting radio telescopes on the dark side of the moon, but that's mostly because NASA was looking for justifications for new moon missions).
The reason Sentinel would be in space is because the atmosphere is bright at infrared wavelengths, and dark asteroids will be relatively bright in the IR compared to the optical so it's a pretty good way to search. LSST goes as far into the IR as you can go efficiently from the ground, and combines a large diameter telescope (8m) with an extremely wide field of view design. This allows sensitive searches for asteroids (amongst many, many other things -- the original goal of the telescope was for cosmology). Sentinel can use a smaller (0.5m) diameter telescope to accomplish the same goal thanks to being in space, allowing it to observe efficiently at the 'easier' longer wavelengths; but it's still outrageously expensive compared to a ground-based search.
tl;dr: the asteroids are fainter at the wavelengths LSST will use, but LSST is a much larger-diameter telescope and thus can see fainter things in the same amount of observing time.
Hubble is in space for a very different reason: blurring by the atmosphere (for reasons related to why stars twinkle) causes the amount of detail you can see for distant objects to be limited from the ground without special technologies that currently only work in the IR, but in space that's not an issue. Hubble has a modest infrared capability (thanks to the WFC3 camera added in its latest repair mission), but that's not why it was designed (in fact, it has bigger advantages over the ground in the ultraviolet -- thankfully for us, the atmosphere absorbs UV -- than in the IR). Hubble's field of view is tiny, though; it's irrelevant for asteroid searches.
posted by janewman at 3:02 PM on May 4, 2014 [6 favorites]
univac, I would assume a unit of volume in this context. But barn is already in use in particle physics as a unit of cross-sectional area, so we need something new, like an Apatasaur or some thing...
posted by Fibognocchi at 4:58 PM on May 4, 2014
posted by Fibognocchi at 4:58 PM on May 4, 2014
Odds are Global Warming will end our species long before the next civilization ending impact event. Or antibiotic resident germs will bring Black Death 2. Or resource exhaustion form fossils fuels running out. Or Yellowstone or another supervolcano will blow up. Or we will kill ourselves with nuclear war.
Chebylansk was exciting but it didn't kill anyone, more damage was done and more fatalities were experienced in the big rainstorm that hit last week. Our current strategy is to deploy more telescopes and continue cataloging objects. We will have a pretty good idea of what threatens is in our neighborhood by 2020. All the attention on asteroids is taking our attention off of the real, eminent threats to our continued existence.
posted by humanfont at 5:18 PM on May 4, 2014
Chebylansk was exciting but it didn't kill anyone, more damage was done and more fatalities were experienced in the big rainstorm that hit last week. Our current strategy is to deploy more telescopes and continue cataloging objects. We will have a pretty good idea of what threatens is in our neighborhood by 2020. All the attention on asteroids is taking our attention off of the real, eminent threats to our continued existence.
posted by humanfont at 5:18 PM on May 4, 2014
janewman, You work in space science, I work in space education. So from this vantage, everyday I learn this: when it comes to asteroids, both science professionals and ordinary people get it.
Not to be merely contentious, media reports of asteroids being near-misses to earth do not equate to a "boy who cried wolf" response due to the simple fact that we are now frequently seeing actual asteroids actually hitting earth. I specifically state now because the modern widespread proliferation of constantly recording/available digital video equipment is what has made this accomplishment possible.
As to what size of impacting asteroid would lead to a cataclysmic event, what I have read on the subject frequently suggests that as small as a 40m meteorite would flatten a city. However, I ma led to believe a 20m asteroid in the appropriate conditions—speed, material, angle of impact—could do enough damage to result in hundreds to tens of thousand real deaths. For instance, the Chelyabinsk meteorite exploded the way it did due to shallow angle of entry. It's main explosion—there were reportedly three—is believed to have been 500 kiloton—that's about .5 megaton of TNT. (By comparison, the combined horrors of the Nagasaki and Hiroshima atomic detonations were in the .033 megaton range.) From a steeper angle, the shockwaves of the explosion would have been driven directly downwards resulting in a shock wave increased "by an order of magnitude".
What more, the Chelyabinsk meteorite exploded around 20 miles overhead with actual meteorites material impact happening some 60 miles away. Yet over a 1000 people were hospitalized, 1000s of windows broken, and all sorts of other injuries, accidents, and damages. This is well-publicized.
Subsequently, my take is an alerted public is a public more eager to support preemptive action.
In fact, this past week I proposed 5 simple ways to jumpstart Space Exploration, #1 being "Headline: ASTEROID X PUMMELS NYC".
The question is not when will an asteroid hit earth and cause untold damage, the question is how to be ready before one does.
Remember, the specific reason the no one realized the Chelyabinsk meteorite was approaching was simply because it came from the direction of the sun and we didn't "see" it. Chances are that had it come in from the other direction because of its "small" size, we still would not have seen it. That is clearly not good enough.
Finally, like eye of newt points out the Tunguska event is not known to be a comet; that is a proposed hypothesis. However, the hole in this supposition is that in 1908 people were sophisticated enough to see—and make record of—the approach of a comet at night.
posted by Mike Mongo at 6:03 PM on May 4, 2014
Not to be merely contentious, media reports of asteroids being near-misses to earth do not equate to a "boy who cried wolf" response due to the simple fact that we are now frequently seeing actual asteroids actually hitting earth. I specifically state now because the modern widespread proliferation of constantly recording/available digital video equipment is what has made this accomplishment possible.
As to what size of impacting asteroid would lead to a cataclysmic event, what I have read on the subject frequently suggests that as small as a 40m meteorite would flatten a city. However, I ma led to believe a 20m asteroid in the appropriate conditions—speed, material, angle of impact—could do enough damage to result in hundreds to tens of thousand real deaths. For instance, the Chelyabinsk meteorite exploded the way it did due to shallow angle of entry. It's main explosion—there were reportedly three—is believed to have been 500 kiloton—that's about .5 megaton of TNT. (By comparison, the combined horrors of the Nagasaki and Hiroshima atomic detonations were in the .033 megaton range.) From a steeper angle, the shockwaves of the explosion would have been driven directly downwards resulting in a shock wave increased "by an order of magnitude".
What more, the Chelyabinsk meteorite exploded around 20 miles overhead with actual meteorites material impact happening some 60 miles away. Yet over a 1000 people were hospitalized, 1000s of windows broken, and all sorts of other injuries, accidents, and damages. This is well-publicized.
Subsequently, my take is an alerted public is a public more eager to support preemptive action.
In fact, this past week I proposed 5 simple ways to jumpstart Space Exploration, #1 being "Headline: ASTEROID X PUMMELS NYC".
The question is not when will an asteroid hit earth and cause untold damage, the question is how to be ready before one does.
Remember, the specific reason the no one realized the Chelyabinsk meteorite was approaching was simply because it came from the direction of the sun and we didn't "see" it. Chances are that had it come in from the other direction because of its "small" size, we still would not have seen it. That is clearly not good enough.
Finally, like eye of newt points out the Tunguska event is not known to be a comet; that is a proposed hypothesis. However, the hole in this supposition is that in 1908 people were sophisticated enough to see—and make record of—the approach of a comet at night.
posted by Mike Mongo at 6:03 PM on May 4, 2014
We are spending billions on space exploration. Why do we need to jump start it? If we have an extra 100 billion or so we should probably spend it on stopping Global Warming. Because the odds of even a Chelyabinsk scale impact hitting NYC or any US city in the next 100 years are incredibly tiny, while the odds that NYC will be hit by a massive flood driven by a storm surge related to sea level rise and climate change in the next 100 years is 100% at the moment.
posted by humanfont at 7:57 PM on May 4, 2014
posted by humanfont at 7:57 PM on May 4, 2014
Possible meteor brings sonic boom over southern, eastern Ontario.
posted by Poldo at 8:39 PM on May 4, 2014
posted by Poldo at 8:39 PM on May 4, 2014
eye of newt, Mike Mongo: you're right, a small asteroid is still a possibility for Tunguska (I had seen claims of definitive evidence for a comet fragment a couple of years ago, and took them at face value; wishful thinking on my part that we'd finally be done with this argument, I guess). The lack of an observed comet isn't really definitive, since once the surface volatiles are lost comets have minimal outgassing (and a comet fragment as small as whatever exploded over Tunguska would be comparatively faint even if it did have a tail).
Mike: an order of magnitude more impact than something that breaks windows still isn't close to a city-killer. It wouldn't be possible for something traveling in the ecliptic plane (the plane where planets and asteroids orbit) to hit Chelyabinsk vertically due to its high latitude, anyways -- for the same reason as why the Sun gets less high there in summer than it would further south. I did a (surprisingly) simple calculation that resulted in a 1 in 9 chance that any object hitting the Earth comes in at an angle less than 30 degrees from the vertical; the places where that could happen are in the tropics, where only ~20% of the surface is land. Comets of a given size can hit much harder, though, as they'll tend to have higher velocities relative to the Earth and can come from any direction.
Still, I of course agree that what a city-killer is exactly depends on a lot of factors (composition, trajectory, etc.). Some amount of thought by people far, far more expert on asteroids than me went into defining the 140-meter threshold in the Congressional mandate for finding near-earth objects; I don't see a good reason to second-guess that work, so that's my shorthand definition for what could typically destroy a city.
I still think the real story here is that we found something so small, not that an asteroid passed this close to Earth. Objects the size of 2014 HL129 pass by us within the radius of the Moon's orbit something like once per week.
posted by janewman at 10:09 PM on May 4, 2014 [1 favorite]
Mike: an order of magnitude more impact than something that breaks windows still isn't close to a city-killer. It wouldn't be possible for something traveling in the ecliptic plane (the plane where planets and asteroids orbit) to hit Chelyabinsk vertically due to its high latitude, anyways -- for the same reason as why the Sun gets less high there in summer than it would further south. I did a (surprisingly) simple calculation that resulted in a 1 in 9 chance that any object hitting the Earth comes in at an angle less than 30 degrees from the vertical; the places where that could happen are in the tropics, where only ~20% of the surface is land. Comets of a given size can hit much harder, though, as they'll tend to have higher velocities relative to the Earth and can come from any direction.
Still, I of course agree that what a city-killer is exactly depends on a lot of factors (composition, trajectory, etc.). Some amount of thought by people far, far more expert on asteroids than me went into defining the 140-meter threshold in the Congressional mandate for finding near-earth objects; I don't see a good reason to second-guess that work, so that's my shorthand definition for what could typically destroy a city.
I still think the real story here is that we found something so small, not that an asteroid passed this close to Earth. Objects the size of 2014 HL129 pass by us within the radius of the Moon's orbit something like once per week.
posted by janewman at 10:09 PM on May 4, 2014 [1 favorite]
Saturday's close shave by asteroid 2014 HL129 . . .
. . . which additional analysis revealed to be merely a small terrestrial rock accidently packed into SpaceX CRS-3's parachute.
posted by Herodios at 6:37 AM on May 5, 2014 [1 favorite]
. . . which additional analysis revealed to be merely a small terrestrial rock accidently packed into SpaceX CRS-3's parachute.
posted by Herodios at 6:37 AM on May 5, 2014 [1 favorite]
I don't know what reports of near misses do, but the Chelyabinsk meteorite caused a sharp increase in donations to the B612 foundation, which is working to launch Sentinel, a space-based IR observatory. It'll orbit closer to the sun than Earth (a Venus-following orbit) so it can look out from the sun to see objects that are invisible from Earth. They're working to raise $450 million to protect earth for 5 or 6 years, and I'm sure they've done the return-on-investment calculation to know that what they're working on is worthwhile.
While working at Google, we were encouraged to publish our "real-life" and "Google Resumes" internally. I stumbled across the resume of Ed Lu, one of the founders of the B612 foundation, which was possibly the most impressive resume I had ever seen. Lettered in wrestling at Cornell, Ph.D from Stanford, postdoc in Solar Physics in Hawaii, Astronaut, Googler, CTO, etc. Anyway, he's the real deal, so I'm inclined to think that Sentinel is fairly likely to work.
About the rise in donations, he said, “It [the Chelyabinsk meteorite] made it [the threat of asteroid-caused extinction] more real to folks,” he said. “There’s nothing like a hundred YouTube videos to do that.”
posted by Hello Dad, I'm in Jail at 12:40 AM on May 6, 2014
While working at Google, we were encouraged to publish our "real-life" and "Google Resumes" internally. I stumbled across the resume of Ed Lu, one of the founders of the B612 foundation, which was possibly the most impressive resume I had ever seen. Lettered in wrestling at Cornell, Ph.D from Stanford, postdoc in Solar Physics in Hawaii, Astronaut, Googler, CTO, etc. Anyway, he's the real deal, so I'm inclined to think that Sentinel is fairly likely to work.
About the rise in donations, he said, “It [the Chelyabinsk meteorite] made it [the threat of asteroid-caused extinction] more real to folks,” he said. “There’s nothing like a hundred YouTube videos to do that.”
posted by Hello Dad, I'm in Jail at 12:40 AM on May 6, 2014
Hello Dad: The Sentinel design is based on identifying the most optimal (in terms of survey time for a not-completely-crazy budget) way to find the near-earth objects, but not the most cost-efficient. LSST, too, would achieve the congressional mandate to find 90% of >140m objects, but it'd take a total of 12 years instead of 5.
~$50 million is the marginal cost for extending the LSST survey to ensure the mandate is reached; LSST costs as much as Sentinel in total, but was funded for other science. Finding killer asteroids is a comparatively cheap byproduct for LSST, but basically the only thing Sentinel would do (the LSST survey strategy is driven in a few ways by the desire to find these things, though -- for instance, it returns to the same region of sky often enough -- roughly every 3 days -- that you can reliably match up asteroids seen on one visit to those seen on the next).
LSST's biggest advantages other than cost are that it is definitely happening -- congressional authorization was given this year, with construction beginning in earnest this summer -- and because of being ground-based, the risk of failure is considerably lower. NASA has repeatedly shut LSST out of conversations on how to find NEOs, as they are invariably most interested in space missions (which help keep NASA labs funded, amongst other things. . .). As a member of the LSST team myself, it's frustrating that it keeps getting left out of the picture.
tl;dr: is it worth an extra $400 million to get a census of killer asteroids by c. 2027 instead of 2034? Answers may vary.
posted by janewman at 10:57 AM on May 6, 2014 [2 favorites]
~$50 million is the marginal cost for extending the LSST survey to ensure the mandate is reached; LSST costs as much as Sentinel in total, but was funded for other science. Finding killer asteroids is a comparatively cheap byproduct for LSST, but basically the only thing Sentinel would do (the LSST survey strategy is driven in a few ways by the desire to find these things, though -- for instance, it returns to the same region of sky often enough -- roughly every 3 days -- that you can reliably match up asteroids seen on one visit to those seen on the next).
LSST's biggest advantages other than cost are that it is definitely happening -- congressional authorization was given this year, with construction beginning in earnest this summer -- and because of being ground-based, the risk of failure is considerably lower. NASA has repeatedly shut LSST out of conversations on how to find NEOs, as they are invariably most interested in space missions (which help keep NASA labs funded, amongst other things. . .). As a member of the LSST team myself, it's frustrating that it keeps getting left out of the picture.
tl;dr: is it worth an extra $400 million to get a census of killer asteroids by c. 2027 instead of 2034? Answers may vary.
posted by janewman at 10:57 AM on May 6, 2014 [2 favorites]
janewman, this thread was made vibrant because of your presence and contributions. I'm going to have to go back and read your other posts. Thanks for all of the above. G̶o̶o̶d̶ right stuff!
posted by Mike Mongo at 2:49 PM on May 9, 2014
posted by Mike Mongo at 2:49 PM on May 9, 2014
tl;dr: is it worth an extra $400 million to get a census of killer asteroids by c. 2027 instead of 2034? Answers may vary.
Hopefully in 2027 we will learn that the answer to this question was "no".
posted by aubilenon at 3:02 PM on May 9, 2014
Hopefully in 2027 we will learn that the answer to this question was "no".
posted by aubilenon at 3:02 PM on May 9, 2014
The asteriod impact of 2028 will be detected in 2021. Unfortunately space junk will cause the deflection missions of 2024 and 2026 to fail.
posted by humanfont at 4:07 PM on May 9, 2014
posted by humanfont at 4:07 PM on May 9, 2014
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