Asteroid misses Earth by 75,000 miles - closer than moo

[Guest]

BBC tends to be a bit of an alarmist when it comes to news like that.....they'll report anything that seems threatening, whereas US based news will report any infractions on it's own pop culture before a genuine danger is reported.

[Guest]

Chris,I'm not trying to be provocative here nor do I bill myself as an expert in any of these matters, but I suspect the biggest reason building warning devices isn't any kind of priority is that we can't do anything even knowing that information.IOW, at our present stage of technology (as opposed to "movie" technology, with Mr. Willis and company) we couldn't have prevented this asteroid from hitting us in any sense whatsoever. I'll go even further on a limb and suggest that we probably couldn't even predict with much accuracy exactly where it would impact the earth (if it were going to).And even if we knew to within the mile or two that it would hit, say, Atlanta -- so what? Impossible to evacuate a US city that size without causing so much more destruction and panic everywhere (since everyone in the entire state of Georgia would have probably tried to leave). One day we may very well have the technology to deflect or otherwise protect ourselves from space borne objects this size (and it may well grow out of Regan's "Star Wars" defense, which would be a fitting irony) but without it there just isn't any point in worrying.The bad news is we're all going to die: good news is we just don't know when.

[Christopher Low 5,341]

If we could discover every object that is a threat, then we could calculate their orbits. These could be integrated several decades into the future, and this would give us an idea if any were on a potential collision course. It's a lot easier to move an object by a small amount over a period of fifty years, rather than a large amount in only one year. Let's face it, if we were looking at the prospect of a massive asteroid impact in fifty years time, then we WOULD try to do something about it.We would have no other choice.Chris Low,ENGLAND.

[Christopher Low 5,341]

Kathy,I suspect that an object 70 metres in diameter would have a far greater destructive power than 4 megatons. The object that exploded over Siberia on 30th June 1908 was calculated to be around 50 metres in diameter, and the explosion was equivalent to 20 megatons.Chris Low,ENGLAND.

[Guest]

Once again, Chris, I'm no expert, but I do read and listen to a lot of them, and they seem to indicate your theory is flawed because celestrial objects such as we're talking about can not be predicted out to that degree of accuracy. If you remember a few years back there was an asteroid they identified and it had a probability of hitting the earth but it was rather small (and it didn't hit the earth) -- and this was only several months in advance.And Even if you were to tell people there was, say, a 25% chance (which is pretty #@@% good a chance in these things) that a large space object would hit the earth in fifty years I am dead solid certain that it wouldn't matter to 99% of the earth's population, most of whom are more worried about next month's rent than a probable event 50 years in their future. Even convincing politicians (who drive the money) it would be in their best interests to support a deflection effort would probably be futile. And I'm not so sure I disagree -- once again, until we really have good technology to do anything about it, I don't think we should worry.We have a *lot* more pressing problems in this world that need a lot of money and attention thrown at them. This ain't one of them, IMHO.

[Guest]

Hi Chris:The paper stated that if this one hit it would be about 10 MT. In any case, we are talking horrific damage.

[B777ER 2,484]

It is common knowlege among astronomers that objects like these are impossible to detect IF coming from the direction of the sun. The sun does a very good job at hiding them. Only when they are inbound INTO our solar system will we have a good chance of detecting them.

[Guest]

OK - where would it have hit if it had?

[Guest]

Before I answer that:Where is FSPlanet located?:-lol http://members.rogers.com/eelvish/elrondlogo.gifhttp://members.rogers.com/eelvish/flyurl.gif

[Christopher Low 5,341]

Kelley,You may not be an expert about this kind of thing, but I have been reading and studying about them for years ! I even have a computer program on my PC that can SIMULATE these close approaches, provided I have up to date orbital elements.There are certainly a lot of problems in the world, and I don't need to remind everyone about the most recent addition, but your attitude (and I'm not trying to criticise you here) is precisely why progress is slow in this field. If a large space object was calculated to hit the Earth fifty years from now, then it is our RESPONSIBILITY to do something about it. Ignoring it because it isn't going to happen in our lifetimes would be a VERY serious mistake. It takes a lot less energy to move an object a few cms (and then let orbital mechanics do the rest over the intervening 50 years), than it does to move it a few thousand kms virtually instantaneously. And let's not kid ourselves here. An object only 10 kms in diameter has the potential to annihilate humanity (and a large percentage of all other life on this planet). Ten kilometres is very small compared to the size of the Earth, but an object of this size would produce a GLOBAL catastrophe. Being on the other side of the planet at the time of impact wouldn't necessarily save you.One last point. Orbits CAN be calculated with this kind of accuracy (at least for inert objects like asteroids) if enough observations are made over a sufficient length of time. That's why we need a dedicated observation program to be undertaken as soon as possible. The cost would be a tiny fraction of one per cent of the world's military budgets. I don't consider that to be too high a price to pay in order to save the planet.Chris Low,ENGLAND.

[Christopher Low 5,341]

Eric,Most of these objects are already in the inner Solar System, with orbits between Venus and Mars. You are probably referring to COMETS, and the vast majority of these do indeed approach the Sun from far beyond the planets. These are a completely different (and more serious) problem than asteroids, simply because we would only be able to discover them two or three years before impact (at best). They would also hit the Earth at much higher velocities on average, since their orbits are vast, and they would therefore have far more kinetic energy than an asteroid in a much smaller orbit nearer the Sun.You are quite correct that any objects approaching from the direction of the Sun would be almost impossible to detect. I say "almost", but there are ways around this problem. Space telescopes positioned far enough away from the Earth to cover the Earth's "blind spot" could help to detect objects of this type (particularly the ATEN asteroids, which have orbital periods less than the Earth, and are therefore almost always on the sunward side of our planet).Best Wishes,Chris Low,ENGLAND.

[Christopher Low 5,341]

Chumley,That's an impossible question to answer. The fact that it DIDN'T hit means that it wasn't GOING to hit. It's orbit would have needed to be changed before impact with the Earth would have been possible, and the impact site would depend entirely on HOW the orbit had been changed.Chris Low,ENGLAND.

[B777ER 2,484]

Chris, Yes of course you are right. I wrote that late last night and was not thinking correctly. You say space telescopes would help but of course no country wants to bear the brunt of the cost of doing it. I think Chris that we would have to actually take a hit from something before the world's goverments would put this potential human extinction scenario into the forefront.

[Christopher Low 5,341]

You are quite right that space telescopes would be hideously expensive, and I wasn't seriously suggesting that THIS course of action should be taken. However, the ground based telescopes could detect at least 90 per cent of all NEA's that pose a threat to Earth, and at a fraction of the cost. In my opinion, this really should be done, and as soon as possible. If nothing else, all inner Solar System objects large enough to cause global catastrophes would be detected (since they will be relatively bright).Chris Low,ENGLAND.

[Christopher Low 5,341]

It's worth noting that an asteroid called HERMES (designation 1937 UB) made a close approach to the Earth in October 1937. This passed by at around 800,000 kms (or twice the distance to the Moon). At the time, this was the record close approach of a known Solar System object to our planet (except the Moon itself, obviously). However, the real worry about this object is that it was lost, and it has never been seen since. It was calculated to be around one kilometre in diameter, which is too small to cause a global catastrophe, but large enough to flatten a large chunk of Europe or the USA. The point here is that we know this object exists, and we also know that it can make close approaches to the Earth. However, we DON'T know where it is today. If it is seen again (and I sincerely hope that it is, before it really does hit us), it will very likely be detected around October/November, since this is where the orbits of both objects are very close together.Happy Halloween !!!Chris Low,ENGLAND.