> A sobering thought.
An even more sobering thought is that even in the present day, if we detected something like that heading our way, there'd be absolutely nothing we could but sit and wait for it to arrive.
An even more sobering thought is that even in the present day, if we detected something like that heading our way, there'd be absolutely nothing we could but sit and wait for it to arrive.
http://en.wikipedia.org/wiki/Torino_Scale
Edit: NASA's JPL maintains the Sentry Risk Table, which tracks all objects that may impact the Earth, with various data points about said objects.
There needs to be time for technology development, deployment, and testing. Tackling an extinction-level event is not something we want to scramble for at the last possible minute, using untried technology.
The probability of something big hitting us is really low, coupled with the fact that we can see it coming since all objects in space are visible. Miss-calculating a trajectory could indeed happen and we may not notice it if it's coming from the direction of our sun, but the probability of that is even lower.
So why would you spend tons of natural resources, time and money for a machinery of dealing with a problem that we may not have in the next 100,000 years? And what should that machinery do in the meantime?
Personally, I think our world has to solve bigger and more imminent problems that can lead to extinction too ... hunger, disease, overpopulation, economic recessions, natural resources running out, global warming, the destruction of the only habitat we know that can sustain life, nuclear wars and the list of things that can happen in the next 400 years can probably go on. Heck, we came closer to extinction during the Cold War than we ever ever did from a comet passing by and the only thing saving us was the few reasonable men in charge, but we may not get so lucky next time.
The majority of objects in space are not visible to us. They only become visible when near and bright enough. Even known comets such as Halley are not visible to us most of the time.
I don't know much on this topic, but if we are able to spot planets that are light years away, then what's the problem with detecting objects that are gonna crash into us in the next 1000 years?
The only problem I can understand is that the sky is a pretty big place, but surely we also have a lot of time to detect such objects.
Never mind the fact that even if we have a telescope that big, the issue is that these telescopes show a microscopically small field of view. There's a whole sphere that would need to be observed, and repeatedly (since the bodies move).
I'm no expert, but as I understand it, the kind of objects we would be worried about are extremely hard to detect as they are dark, cold and relatively tiny.
At the same time, our "eyes" can only look at tiny patches of sky, generally through the distortion of our atmosphere for only a portion of each day with parts of the sky only visible part of the year. Furthermore, we generally have those eyes trained to other, known targets - stars, galaxies, nebulae and all that.
Consider that we didn't spot Apophis [1], which is set to come extremely close, until 2004 even though it's on our lawn [2] in terms of distance.
There is an effort [3] or two [4] afoot related to tracking asteroids and a new DARPA [5] program for tracking our own local junk.
1: http://en.wikipedia.org/wiki/99942_Apophis
2: http://www.howcloseisapophis.com/
3: http://www.skyandtelescope.com/news/160839035.html
I am not sure if this is in line with Agile principles like YAGNI.
It's hard to estimate how long it takes for another humanity to develop if we screw it(so we don't know iteration length), and there is the problem of telling them what we did wrong after we were destroyed.
Smaller stuff, from maybe 10kt up to 1Gt (Tunguska was ~15 Mt), though, we can reliably predict its course and evacuate the affected area.
To detect the small stuff at close range, of course, you need to be able to detect the big stuff a ways off. The problem is that massive star surveys are essentially a brand-new thing now that we have Big Data capabilities (we still get a substantial amount of info from scanner photographic plates of the last century). The astronomical community has mostly been focused on producing expensive 1-2 unit runs of a brand new design every decade, each much bigger and better than the last. Survey telescopy, however, is perfectly amenable to economies of scale in large numbers of small scopes, and to the data from a single-purpose survey being used for dozens of different scientific goals.
http://www.fallingstar.com/ , the ATLAS project, is a minimum viable project for this purpose, using small COTS telescopes & sensors to scan the sky rapidly & systematically for objects that have photometric characteristics of something that is headed our way, a few days or a few weeks from Earth.
I see no reason why we shouldn't build twenty of those, scattered around the world, just for immediate situational awareness. We could initiate the project and have it done in six months.
On a longer-term basis, I think rather than constructing things like LSST under the old paradigm, we should be focusing on smaller, 1-2m telescopes (like PAN-STARRS, albeit perhaps without the extraordinary sensors) in very large, economical quantities. Mechanizing the production line is something that's only really been done for much smaller telescopes.
When you have a large, distributed array of automated telescopes, you can sweep the sky quickly and resiliently to weather conditions, or you can turn a portion on a single target that needs a higher signal to noise ratio, for confirming observations, and perform like a much larger telescope's light-gathering ability.
Lastly, there are projects like the Gaia mission that are doing space photometry. While extremely data-starved (better space communications via radio relays & lasers really needs to get here), Gaia would be in an ideal position to detect all the Earth-crossing NEOs that we can't realistically see from the ground due to the sun's glare... if it was at Venus L2 rather than Earth L2, and ideally if there were half a dozen of them instead of one.
The longer out we see it, the better we can deflect it - and our predictive abilities are in the hundreds of years range if we actually bother to spend the money on detection as if it were as important as space toilets on the ISS. The tech is here.
http://slant.co/topics/what-is-the-best-way-to-stop-an-aster...
We could blow it up with nukes.
We could put a relatively heavy space probe next to it and deflect its course.
Anyway, I thought the OPs comment was likely more facetious than anything. Only in Hollywood can we expect a perfect ending.
After you've figured all those out the stage is set and you get a menu:
- party like it's 2012
- attempt to deflect it
- brace for impact and deal with the aftermath
You'd have to develop the vehicle (and the fuel expenses to get the right velocity / direction are going to be terrible, they may be beyond current tech to make a manoeuvre like that, imagine meeting an oncoming bullet by matching speeds and direction where the bullet can come from any direction and you're sitting on a spinning ball), a plan to deflect the mass (by then you'll have burned up a lot of your time budget) and so on.
Maybe, for very small values of maybe.
I also suppose that industriousness would be helpful for taking one's mind away from the reality of that impending doom.
But hell, nukes to deflect a comet? Sure, we may as well try it -- but I only suggest doing this if we are 100% certain that the comet will both hit us and destroy us. We could conceivably cause our own extinction via a false positive provided by some faulty monitoring device - wait, did that already happen? Nevermind.
Edit: Also, it just occurred to me the possibility of deflecting a comet (which was never in our path) into our path, instead of away from it, which is really great material for a Hollywood comedy.
If we are sufficiently uncertain about the comet's path, we might accidentally deflect it towards us. Obviously, if this is just as likely as deflecting it away from us, it would not be worthwhile to try. But most likely we would be able to reduce the probability of a catastrophic impact even after taking into account the possibility of such an error.
But I would not be surprised if Green political parties argue that risking a few km^2 contamination is worse than a certain dinosaur killer... :-)
http://en.wikipedia.org/wiki/1966_Palomares_B-52_crash
"The non-nuclear explosives in two of the weapons detonated upon impact with the ground, resulting in the contamination of a 2-square-kilometer (490-acre) (0.78 square mile) area by plutonium. [... another which fell] into the Mediterranean Sea, was recovered intact"
If a lunch failed and "nuked" the launch pad, I hope we'd just move on to another continent and try again (and again)