I can see why it is fascinating to keep an eye on these things but we 'need' to keep an eye on them just as much as we need to keep an eye out for invading aliens.
We'll know it when it happens, trust me on that one.
Until then it doesn't matter. If and when it happens we'll be dealing with the aftermath long before we'll be able to have a handle on what we can do about the event itself.
You could even argue that this is one of the few cases where foreknowledge would not help at all, especially not in the case of a very near miss (or is that a near hit ;) ).
> We'll know it when it happens, trust me on that one.
But wouldn't it be nice to know it before a giant tsunami wipes out the whole pacific coastline?
How costly is it compared to what damage it could generate? How costly would be to avert such a disaster compared to the cost of digging a mile-wide crater in central Europe?
If we knew of a mountain-sized rock headed towards Earth we would be able to prevent a disaster, provided we had an early warning system in place. IIRC, a Delta IV heavy can carry a Tsar-bomba-sized device, plus a booster to put in the correct trajectory. It wouldn't take long to assemble a couple devices like this and try a couple approaches, from deflection to blasting it to small pieces (yes, I would prefer a couple hundred airblasts over a single mountain hitting the surface).
I think the politics of putting a gigaton device on top of a rocket are much more complicated than the engineering.
I think you are overestimating our capabilities in terms of logistics and engineering.
That's not to be fatalistic about it, it's just harsh reality that if we knew that a major impact was to take place in 6 months to a years time (which would leave an enormous amount of room for error in terms of things that look really scary but turn out to be misses after all) there would not be much that we'd be able to do about it at all, even if we we could get all the politicians to pull in the same direction for once.
Just imagine, at that distance the difference in trajectory measured versus actual would have be only a fraction of an arc-second to turn an all out disaster in to a spectacular display of fireworks.
So the timeframe within which we can determine with real certainty that there will be a strike and where it will hit is very short, short enough that you could evacuate all you want, you might be sending people in the exact wrong direction.
It's a cosmic crapshoot and the speeds and distances involved are such that we'd need to improve our game considerably before we'll be able to make an accurate prediction.
Against such forces of nature we are but ants, and all our technological achievements of the moment amount to preciously little. It's possible that in the future we'll be able to do something about this sort of event.
My best bet is that we should spread to multiple places in the solar system first, the galaxy at a later point. After all, we have a single point of failure situation here, all our eggs are in this single basket called 'Earth' and if one of these cosmic freight trains hits us hard enough it could well be game over for humanity.
While I agree we would not be able to do anything in a 6 month timeframe, any 100+m rock with large enough impact probability would command much more attention (and better instruments - all of them, most probably) and have much better data than current tracked objects. If we ignore the threats we can do nothing about (the island-sized ones) and focus on the ones we can (mountain and smaller) the picture is much better. While we can do nothing about freight trains, we can deflect (or fragment) golf balls.
Certain extinction is a powerful incentive. Humans put a man on the Moon because a dead president promised that. I certainly imagine a global disaster can focus out attentions.
I think you overestimate the effect current technology can have on a meteor large enough to significantly dent the human population. Some of the objects mentioned in the article are on the order of hundreds of kilometers. Mountains aren't even on the same scale as that. It's beyond our ability to even scratch.
I think you underestimate the value of stopping smaller impacts.
http://en.wikipedia.org/wiki/Impact_event#Sizes_and_frequenc... claims that an incident on the size of the Tunguska event (would could take out a large city) happens every thousand years, and to prevent it we need to move an object with a diameter of 50 m or so. A object on this scale might be in the 10,000,000 kg range. We'd like to deflect it 6000 km or so (ie make it miss the Earth). We have about 600,000,000 seconds to do so. If we can give it a sideways momentum of 100,000 kg*m/s, we'll be fine. While difficult, this may be within our means. (Tapping it with a nuclear bomb is only the most obvious.)
A landing on a near earth asteroid, 34 Km across, with a 56 Kg payload. Eros is one of the 'easiest' (for want of a better term) asteroids you might want to visit.
The two asteroids this article is about were discovered last week and are here now.
What part of while difficult, this may be within our means do you interpret as meaning easy?
The person I was replying to was making the argument that there is no point to trying to categorize these things because we can't possibly do anything about anything we learn. My point is that the most common objects which can potentially cause significant damage are small enough that we could, given enough warning, plausibly do something about them.
The major problem of nuking something like that is that you can get more pieces that are out of the control. The goal is just to deflect. It's harder than it appears.
I'm aware of that problem. However it turns out that if the pieces you get are small enough, then they will individually burn up in the atmosphere without causing damage.
Moving most of a 50m rock out of the way and creating a bunch of small debris in the process is probably OK because the debris pieces are unlikely to be big enough to get through the atmosphere. (Satellites in orbit would be put at increased risk.)
Attempting the same on a 500m rock would be a different story.
Not only that - if you blast the thing into small pieces, most of them may miss the Earth completely. You will still have to track a lot more objects, but between being dead and having to fund such a project, I am certainly in favor of #2
They are completely different things. Star wars was meant to intercept immediate threats minutes after detection with light sub-orbital missiles with conventional warheads. A deep space shield would be Energia or Delta IV-class boosters with high-yield nuclear payloads meant to intercept targets years away months after detection on varied mission profiles adapted to the composition of the specific threat. It's a completely different game.
Assuming the universe is around 14 billion years old, a million years is like comparing a blink to about 70 minutes (average speed of a blink being somewhere between 300ms and 400ms).
Does a blink feel short in comparison to 70 minutes? That's a matter of perception, I guess...
"Keeping an eye on NEO is extremely important, given the large number of unknown space rocks that lurk in outer space."
So it's important to keep track of the few that we know of, because of the unknown numbers of ones we don't know of? And what if we do track them? What do we do with this information? It's not like we're going to move the things or move the planet out of the way. Tracking NEOs does nothing for us, with maybe the exception of mapping trajectories for deep space probes. How many of those do we launch in a year? And given that we don't know the full implications such an impact would have, isn't the psychological effect on hysterical populations enough of a reason to heed "ignorance is bliss"?
If we don't track them, we wont develop better technology to track more of them. The more we track, the more information we have about what's out there. The more information we have, the better decisions we can make about the risks and how to reduce them.
What's the alternative. Ignore the issue until the inevitable happens?
You obviously want to track known objects as well as discover new ones. That has happened at a pretty quick pace in the last few years, thanks to increased professional effort (while amateur astronomers discovered most asteroids only a few years ago nowadays most are discovered by professionals).
Asteroid impacts are one of the few natural disasters (the other probably being floods) that we could actually be able to prevent from happening. It’s a good idea to be on the lookout. Oh, and even if we can’t prevent the rock from falling we can still evacuate in a timely manner (e.g. in case of an asteroid hitting the Pacific and causing a Tsunami).
Sure, if we discover the asteroid a week before it hits we can’t do much. But if we know a few years in advance that an asteroid will cross paths with Earth we can actually do something about it (since relatively minuscule changes in the asteroid’s trajectory can move it out of the way). One way would be to simply park a spacecraft next to it. The gravitational pull of the spacecraft which keeps its distance with thrusters can move the asteroid ever so slightly. It might also possible to hit the asteroid just right with a kinetic impacter (i.e. a big hunk of heavy metal) and slightly whack it.
It’s not expensive. People are actually working on this. And they better be, ask the dinosaurs. (If you can.)
We'll know it when it happens, trust me on that one.
Until then it doesn't matter. If and when it happens we'll be dealing with the aftermath long before we'll be able to have a handle on what we can do about the event itself.
You could even argue that this is one of the few cases where foreknowledge would not help at all, especially not in the case of a very near miss (or is that a near hit ;) ).