Sunday was a really long day around Chateau Steelypips, and I couldn't see staying awake to watch the premiere of Phil Plait's Bad Universe on the Discovery Channel, so I'm way late in writing about it. I DVRed it, though, and watched it last night.
The theme of the premiere/ pilot was killer rocks from out of space, and focused on Phil getting his MythBusters on to test various ideas about asteroid or comet impacts and how to stop them. They blew up a scale model, shot projectiles into various types of rock to simulate nuclear bombs or kinetic impacts, all in the name of testing what would happen if we tried to destroy or deflect an incoming killer rock.
On the whole, it was a good Discovery Channel type program-- Phil was very enthusiastic, as he tends to be, and the explosions were all explodey, which is what you expect from this sort of thing. There were a couple of minor holes I would've liked to see filled in, though, and one big open question.
They started off by looking at what nuclear explosions would do to various types of rocky asteroid, simulating the nuke by firing a projectile into the rocks at high speed. For this test, they just looked at whether they could break the rock up or not. Later on, they looked at the effect of using a "kinetic impactor" to try to deflect an incoming rock, which they simulated by firing a projectile into a big rock, and looking at whether the impact moved it significantly.
The problem I had with this was that they never really connected the dots between these two. That is, the simulated nukes all rocked their targets back by at least as much as the simulated kinetic impact did, but nothing was said about the change of momentum. Would the nukes be less effective at shifting the orbit of a space rock than a non-exploding projectile? Would the pieces broken off by the kinetic impact complicate the problem? he two tests were treated as completely separate things, but they could easily be tied together, and that would've been good to see.
The other nitpick I had was with the test trying to use a laser to melt stuff off a simulated comet. The laser being used with "the most powerful hand-held laser available," but there wasn't much said about that choice. Why a hand-held model, given that there are non-portable lasers that put out quite a bit of power? Was the power level chosen based on the scale, or did they just want a hand-held model to facilitate the shot of Phil grinning maniacally while tracking the "comet"along an air table? And did it produce any change in the motion at all?
(I am, of course, a laser nerd, so this question was more important to me than it would be to most of the expected audience.)
The big open question is: what does Phil (or somebody at Discovery) have against Sydney, Australia? Why was Sydney chosen as the target for the simulated impact? Did somebody involved with the production have a bad experience in Australia? Paul Hogan stole their girlfriend? Or did they just have an animator who happened to have a really nifty model of Sydney for some reason, so they used that?
Anyway, like I said, it was good fun. If you didn't catch the premiere, I'm sure they'll be re-running it at some point, so check your listings and set your DVR accordingly.
(The post title is not a negative comment on the show-- I'm just powerless to resist obvious jokes.)
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Phil live-Tweeted the show and in doing so he explained that Sydney was chosen because it was basically the one city with iconic landmarks that hadn't yet been blow up a zillion times in movies already.
I don't know, but I've heard it speculated that Sydney was chosen because it was the site of the colony drop in Mobile Suit Gundam. I have no idea whether or not Phil (or someone else working on the show) is a fellow mechahead, but that's the first thing that popped into my mind when I heard what they were going to do.
Ah, that explains it.
Why a hand-held model, given that there are non-portable lasers that put out quite a bit of power?
I didn't watch (no cable), but I think you may have answered your own question here:
...or did they just want a hand-held model to facilitate the shot of Phil grinning maniacally while tracking the "comet" along an air table?
It probably would have been more work to get a non-handheld laser to track the fake comet.
I've seen too many programs dealing with mere rocks, I would rather see one explaining what to do when we find the Earth on a collision course with Jupiter.
How do we move the Earth's orbit away from the ecliptic plane? Would detonating all the atomic arsenal over one pole have any noticeable effect on the orbit? Would some humongous rocket engines mounted on a pole do the trick?
I would rather see one explaining what to do when we find the Earth on a collision course with Jupiter.
We do absolutely nothing, because we are overwhelmingly likely to be dead before that happens. To get onto a collision course would require one or both of outward migrating Earth or inward migrating Jupiter. Before their orbits cross, Jupiter is likely to do one of two things to Earth: kick it out and leave us freezing to death, or kick it in and leave us baking to death.
Not that that's likely to happen short of a major perturbation due to a closely passing star. The fact that we are around suggests that Earth's orbit has been stable for a few billion years. The evidence for Jupiter's orbital stability is less strong, but I think we can rule out outward migration to its present orbit, at least from inside of the orbit of Mars.
Actually migration (as in spiral) requires constant energy expenditure so what I was thinking instead was some body altering the eccentricity of Jupiter, say the 9th as yet unknown giant planet which only visits Solar System once in a few million years, comes very close or hits Jupiter sending it our way.
And we could easily survive on our orbit up to the impact if the impact was the first time Jupiter came close.
So let's say we have a 10 years left until impact, is there any practical way to alter Earth's orbit?
Newton's law implies we would have to launch large amount of mass with huge velocity in one direction to give Earth enough momentum in the other direction. But it's hard to say how much would be enough, after all if the impact is many years away a slight alteration of our orbit might be enough to miss. Though miss would likely not be good enough in this case as just passing close by would get us catapulted into an inhospitable orbit (still better then dying outright, as if we managed to survive we could try to change the orbit again).
Alternatively we could hope that Jupiter is literally a gas giant and that our tough little planet will simply poke a hole in it and emerge on the other side unharmed ;).
Though miss would likely not be good enough in this case
Definitely not, if we pass within about 60 Jupiter radii. In that case, the energetic particles trapped in Jupiter's radiation belts would fry anybody, as well as any electronic equipment, not sufficiently close to Earth's magnetic equator (I'd have to crunch some numbers to tell you how close is close enough). We'd get to watch some amazing auroral displays while dying, though.
More realistically, if we had the capability to deal with this scenario, we would also be capable of launching lots of little space colonies, some fraction of which might survive.
"Slamming into the Jupiter" scenario is not as crazy as it sounds. It's not actually likely to happen (Jupiter is BIG).
But we might actually hit Mercury! It has a known orbital coupling with the Jupiter, and Mercury's orbit seems to be chaotic. And there are some trajectories where Mercury actually can slam into the Earth.
http://www.nature.com/nature/journal/v459/n7248/full/459781a.html
Phil Plait comes up with mildly clever name for his show and thatâs about all - pilfering, rehashing virtually standard info from recent (and better) shows. Phil goes for ride in jet, âgeeâ havenât seen that done beforeâ¦yawn... flamboyant mediocrity.
Phil promotes âMy new TV showâ, ââ¦read my bookâ¦â âwin a signed copy of my bookâ and "Definitely want more Phil", "Phil rocks!" âholy crap I canât wait!â just in first paragraph at Discovery web site for his show. Now who wrote that?