Astroid Defences

[Мастер]

This one could go in the science/technology forum as well, but I'll put it here.

Here is the story.

http://www.universetoday.com/99801/45-m ... on-feb-15/

It describes an asteroid which is due to pass very close to earth on Friday, mentioning

No known asteroid has ever passed so near to Earth.

I believe that in fact some known asteroids have passed closer to Earth, shortly before crashing into it, but I'll assume they either mean "within recorded history" or "without crashing into Earth immediately thereafter". So no worry there. But of particular interest is this quote.

So the local effect on human cities for example of a 50 meter wide asteroid impact would be deadly and utterly devastating. But it would not be catastrophic to all life on Earth. Nevertheless, at this moment, Earth has no defenses against asteroids other than talk.

What's that? Talking is a defence against asteroids? Should we all be talking Friday? Do we need to talk at the same time? Do we need to say the same things? In the same language?

The article is quite sketchy on this point.

[Heid the Ba]

I think the talk all has to be in english and consist of a reasoned, rational discussion. Foreign jibber-jabber, however well meaning, is unlikely to provide a stout barrier.

[Arneb]

No known asteroid has ever passed so near to Earth.

I believe that in fact some known asteroids have passed closer to Earth, shortly before crashing into it, but I'll assume they either mean "within recorded history" or "without crashing into Earth immediately thereafter".

"Known" is the key. This is the closest encounter of an asteroid that was in the catalogue of known NEOs before making this particular pass.

Re. the talk, OK, it wasn't their best joke. I think it is worth an honorable mention, though, that people are at least thinking and talking about what a real asteroid defence could look like, what physical principle it would employ and how we could finance and maintain it. That's not much, but it isn't nothing either.

[Enzo]

Well if talk is an effective defense, then my wife alone will present an unpenetrable barrier for any future incoming rocks.


yes, she will.



won't you , dear......

[Мастер]

No known asteroid has ever passed so near to Earth.

I believe that in fact some known asteroids have passed closer to Earth, shortly before crashing into it, but I'll assume they either mean "within recorded history" or "without crashing into Earth immediately thereafter".

"Known" is the key. This is the closest encounter of an asteroid that was in the catalogue of known NEOs before making this particular pass.

Re. the talk, OK, it wasn't their best joke. I think it is worth an honorable mention, though, that people are at least thinking and talking about what a real asteroid defence could look like, what physical principle it would employ and how we could finance and maintain it. That's not much, but it isn't nothing either.

I also almost commented on another aspect of this article, which has since been corrected. It currently refers to this asteroid as impacting (if, counterfactually, it were to impact) with 2.4 magatons of energy. Originally, it said the dinosaur asteroid had 2.4 megatons, which absolutely floored me - could it really be that the asteroid which led to a mass-extinction event released only 5% of the energy of one particular Soviet nuclear test?

It would seem the answer is "no".

[Lianachan]

Well if talk is an effective defense, then my wife alone will present an unpenetrable barrier for any future incoming rocks.


yes, she will.



won't you , dear......

You should probably think about forming your own impenetrable barrier for future incoming rocks, and soon.

[Lianachan]

I think the talk all has to be in english and consist of a reasoned, rational discussion. Foreign jibber-jabber, however well meaning, is unlikely to provide a stout barrier.

Surely it should be Psalms? What use is reasoned, rational discussion? You're quite correct that it should all be in English, though. We can't risk having our salvation drowned out by billions of foreigners chattering on in their bloody lingo.

[Heid the Ba]

Obviously Russian doesn't work.

[Halcyon Dayz, FCD]

I hope the 2013 Russian meteor event will be the critical one that finally kicks the politicians into action.

Just as well nobody had to die for it. (Yet.)

[Enzo]

Oh I can see the conspiracies brewing already. We been hearing about the big space rock going to come real close but can't possibly hit us, even when it flies under our satellites. And then BAM the thing hits Russia. What ELSE are they not telling us?

[Мастер]

Oh I can see the conspiracies brewing already. We been hearing about the big space rock going to come real close but can't possibly hit us, even when it flies under our satellites. And then BAM the thing hits Russia. What ELSE are they not telling us?

Yes, doesn't it seem very suspicious that this "space rock" hit America's cold-war rival? It's not like it's the biggest country in the world by a factor of almost two, or anything like that.

[Мастер]

I should add that Chelyabinsk was one of the centres of Soviet nuclear weapons development. They also built tanks during the Great Patriotic War. Closed to foreigners until 1992.

[Enzo]

Chelyabinsk there, we have Chely Wright here. Coincidence?

[tubeswell]

So how fast was it going? Do they make rockets capable of that speed?

[Enzo]

I heard a figure of something like 30 miles a second.

[Lance]

And I heard 30K mph.

[Arneb]

AFAIK, everything in the vicinity of Earth's orbit moves at roughly the orbital velocity of the Earth. If it caught up with the Earth from behind, its velocity relative to Earth would have been just the velocity that anything falling to Earth gains just from falling: Around 11 km/s. If it came on in in a head-on collision, the velocity would have been 30 km/s x2 + 11km/s from falling to Earth, so max 71 km/s.

30 km/s is 67k mph, btw. So, the collisional speed seems to have been a midrange one.

[tubeswell]

AFAIK, everything in the vicinity of Earth's orbit moves at roughly the orbital velocity of the Earth. If it caught up with the Earth from behind, its velocity relative to Earth would have been just the velocity that anything falling to Earth gains just from falling: Around 11 km/s. If it came on in in a head-on collision, the velocity would have been 30 km/s x2 + 11km/s from falling to Earth, so max 71 km/s.

30 km/s is 67k mph, btw. So, the collisional speed seems to have been a midrange one.

Yes I read in some on-line tabloid that it was 30km/s, but we all know that you can't trust Rupert Murdoch or anyone who works for him. So which direction did it come from? Anyone know?

[Arneb]

The descriptions I read had it coming in from the East.

[Lance]

Hmm. Looks like it's moving the same direction as Earth.



ETA: Ah, here:

http://neo.jpl.nasa.gov/news/news177.html

Asteroid 2012 DA14 will be closest to Earth on February 15, 2013 at about 19:24 GMT (2:24 p.m. EST or 11:24 a.m. PST), when it will be at a distance of about 27,700 kilometers (17,200 miles) above the Earth's surface. This is so close that the asteroid will actually pass inside the ring of geosynchronous satellites, which is located about 35,800 kilometers (22,200 miles) above the equator, but still well above the vast majority of satellites, including the International Space Station. At its closest, the asteroid will be only about 1/13th of the distance to the Moon. The asteroid will fly by our planet quite rapidly, at a speed of about 7.8 kilometers/second (17,400 miles/hour) in a south-to-north direction with respect to the Earth.

[Arneb]

The fact that the impactor came from the East while 2012 DA14 came from the South was also a point from whicht you could see that the two had nothing to do with each other.

My back-of-the-envelope scribble, of course, was related to the impactor, not 2012 DA14.

[tubeswell]

When's the next one due? Anyone?

[KLA2]

I think I have said this before on this board. The earth shakes, bakes, rattles, and rolls, floods, freezes and yes, gets hit by asteroids

with all of our marvelous technology the only disastrous event we can potentially prevent is an asteroid strike. We know it is not a question of if, but only when.

Preventing this will require a concerted coordinated effort on the part of the world's great powers.

this can only happen if the world's great powers are more concerned with saving the planet than in destroying their rivals

actually, if I was concerned with such things, I would be more worried with Yellowstone exploding, taking out the western half of the United States and a big chunk of Canada, than an asteroid

the asteroid, however, is theoretically preventable, not so much the other disasters.

How disturbing that we, possibly, the most (only?) intelligent species in the universe, might die of our own stupidity.

[tubeswell]

...We know it is not a question of if, but only when.

Preventing this will require a concerted coordinated effort on the part of the world's great powers.

this can only happen if the world's great powers are more concerned with saving the planet than in destroying their rivals
....
How disturbing that we, possibly, the most (only?) intelligent species in the universe, might die of our own stupidity.

Yes I know what you mean. I feel the same way about this:



plus this:



in the context of this:

[Arneb]

Very interesting discussion.

I can totally see KLA2's point - although I'd like to add that a collision with an Oort cloud comet on a parabolic trajectory might well be unavoidable - but my personal worry and priority would be what tubeswell mentioned.

Therefore, I drive a big car, live in a house with a crappy heating system and old wooden (if double-paned) windows, and I prefer to leave the computer on when I leave work. Did I mention my holiday on Hawai'i?

Yeah, we Germans are so carbon footprint-conscious, arent' we?