…and is this a good thing or a bad thing?
The unleashing part, I mean, not the Irish part.
Its good news if you like watching MTV with the sound off.
Gotta love those dusky gals from the UK, even though they end up marrying old actors who could be their grandfathers…
So, I finally did the calculations, for how to “mess up the orbit” of the Moon enough that it’d break up. First step, we need to get the Moon down to the Roche limit at perigee. The Roche limit is given by L = (2M/m)[sup]1/3[/sup]r , where M is the mass of the Earth, m is the mass of the Moon, and r is the radius of the Moon. This is the height at which it’ll break up. Now, we’ll need a transfer orbit to get the Moon down that limit, at perigee. Using conservation of energy and angular momentum, we can find that the orbital speed at the apogee of that orbit is given by V[sup]T[/sup][sup]2[/sup] = 2GM(1/R-1/L)/(1-R[sup]2[/sup]/L[sup]2[/sup]) , where G is Newton’s constant and R is the present radius of the Moon’s orbit. To get the Moon onto that transfer orbit, we need to change its momentum by [symbol]D[/symbol]p = m(V - V[sub]T[/sub] , where V = (GM/R)[sup]1/2[/sup] is the present orbital velocity of the Moon. The most efficient way to generate that change in momentum, using a given amount of energy, is to throw material up off of the Moon’s surface at exactly the Moon’s escape speed, so E = [symbol]D[/symbol]pV[sub]e[/sub]/2 , where the escape speed is V[sub]e[/sub] = (2GM/r)[sup]1/2[/sup]. If we throw all of this together, we can solve for the minimum amount of energy needed to bring down the Moon. Plugging in G = 6.67E-11 Nm[sup]2[/sup]kg[sup]-2[/sup], M = 5.97E24 kg, m = 7.16E22 kg, R = 3.84E8 m, and r = 1.74E6 m, we find that E = 6.6710[sup]28[/sup] J, or using Bad Astronomer’s conversion factor of 1 megaton = 4E15 J, that’s 9.56*10[sup]6[/sup] megatons, a factor of fifty thousand times the bomb in the movie, at an absolute minimum.
And besides all that, Chronos, the purpose of the detonations in the first place was to create underground caverns for people to build cities in.
Underground, so there wouldn’t be any ejecta, so there wouldn’t be any reaction mass.
Is it possible for an explosion of the size you specify, 9.56*106 megatons, that was wholly contained by Luna’s surface, to disrupt Luna’s orbit?
I’m guessing no, but you’re the scientist.
Less interesting note about him - he’s also the same ‘artiste’ that brought us the incredibly stupid and unexciting ‘Tomb Raider’. So it may be okay to presume he’s just not a good director.
Well, I think the idea is that the explosions were supposed to be contained underground, but they weren’t. The easiest way to get a bunch of rock flying upwards would be to have a bunch of rock above the explosion, so subterranean (well, actally, sublunan) explosions would work. If, of course, they were big enough.
Credit where it’s due, by the way: I was impressed that they got the holograms right. There’s none of this projection into thin air nonsense; you can only see the image when you’re looking through the plate. Holography is very seldom portrayed accurately in even the best science fiction. Of course, current technology is nowhere near capable of real-time animated, computer generated, photorealistic images, but the physics is there. It’s conceivable that in 30 years, we will have that.
They weren’t contradictory, we just chose to focus on different aspects of the story. kaylasdad99 is correct in that Weena disappears and is presumed dead by the TT, and I am correct in that the TT returns to his own time to tell the story to his friends and then takes off for adventures in times unknown.
What I find interesting is that so many adapters of The Time Machine feel the need to put H.G. Wells into his own machine. Both the 1960 version of the movie, and the 1979 movie Time After Time did this (the TV show Lois and Clark also did this, but in that case it was more of a double ripoff of Time After Time and Back to the Future so I don’t count it).
So why do we think this is? Why does Wells have to be his own Time Traveller? Is it just because he didn’t name his character?
I always thought it was an homage, Fiver. After all, he did invent a genre.
My own personal nits to pick.
So the hero builds the machine. He goes back in time to meet with his fiancee. But he gets there way early to intercept her. Now, we all understand that the Time Machine moves in time but not in relative space. So there he is, four years earlier, in the lab, early to meet his babe. Future hero is with babe, watching her get run over by car. Meanwhile, past hero arrives at home late and in a panic. He runs into his lab, and…
LO AND BEHOLD! A shiny Time Machine sits in his lab! Hmmmm, that wasn’t here this morning. Now we’ve already been shown in the begining of the film how easly distracted our hero is by shiny new technology. There sits an amazing new device! (Watch carefuly. I do not think the curtains that hid the device later are up in the begining of the film.
The imaginitive reader can take things from there…
I too wondered why no one noticed the odd time bubble floating in the lab for a hundred years…You could see it from outside, that much was shown a few times…
There was a wonderful time travel story by an author who escapes me at present…(was it Heinlein?) who wrote in the travelers perspective untill near the end. The story breaks off in mid sentence, and shifts to the external, where the time traveler is a museum display with a placard that says something to the effect that, sensitive devices measure the time traveler’s fingers actually moving as he types his story, at some incredibly slow rate… His perspective is that of the Guy in the film, with everything around him moving incredibly fast. All others see him as a still, hyperslow-moving man in a stasis…
I think the movies wanted to take place in a world where ‘The Time Machine’ was written by H. G. Wells, instead of an alternate universe where the story wasn’t written, but it did really happen. Now, in the book the time traveller tells a group of people about his adventure, and none of them bear much resemblance to H.G. Wells. If we suppose that the time traveller was not H.G. Wells but existed in the same universe as Mr. Wells then he would have had to tell someone else about his adventures, who relayed them to Mr. Wells who then wrote a first-person narrative based on it. It is a lot tidier if the traveller is Wells himself - that way he’s capable of recording all the details, thoughts, and feelings the traveller experienced on the trip as the novel, and partially explains why nobody else believes anyone ever built a time machine - the traveller did a cover-up by presenting it as fiction.
There’s also the fact that Wells was quite the futurist and he would be a more interesting observer of the future than some generic English physicist/mathematician.