Tilting The Earth


Guest and the rest didn't do much homework.

When McKern's science correspondent `speculates' that the planet may have been further tilted, he was way behind the obvious. Several things would have left no doubt at all.

Firstly, the Earth's core is a gigantic ball of iron lying in a hot slurry. It's the densest part of the planet and massive. So if the body of the planet had swung, the core's own inertia would have left it more or less in the same place. This would have caused the magnetic pole to remain in-situ, but the tilted planet would have resulted in a relative shift of hundreds of miles. Every compass and any scientific apparatus dependant on magnetic field would therefore have been out of kilter. In 1961, many larger vessels were using radar and RDF to establish their positions. But these were not always practicable in the middle of the ocean. Most small vessels and private yachts still employed `dead reckoning', which required charts, a compass and also a sextant. There was no sat-nav in 1961.

Regarding the sextant: a tilt in the planet would have caused the sun, moon and all stars to suddenly change latitude, making a complete mockery of day to day navigation.

That same phenomenon would have affected hundreds of astronomical telescopes throughout the world. Their `equatorial mounts', using an axis parallel to the world's, enables them to track cellestial objects day by day and night after night - especially radio-telescopes. Once again; they'd suddenly be finding themselves out of kilter. Even today, most amateur astronomers' rule of thumb for celestial polarity in the northern hemisphere is Polaris - the north polar star. Suddenly it wouldn't be, and all `equatorial mounts' would inexplicably need adjusting. Astronomers are meticulous observers, and they talk.

Likewise, the change in latitude would effectively create a change in season and climate. That bit they got right, but it would also have caused a lengthening or shortening of the day, depending upon northern or southern latitude. Film-makers might not spot that, but you can bet that farmers would.

And finally, returning to the inertia issue; like the centre of the Earth only moreso, the oceans are fluid too. If the Earth shifted suddenly over a period of a few days, the sextillions of tons of water would lag behind, causing a colossal `reverse-flow' spring tide. Then they would flow back, with the added impetus of a restoring moment, and we would see the sort of inundations depicted in `The Day After Tomorrow'. No seaboard city - including London - would be spared. That wouldn't have been a bank of mist oozing up the Thames, but a vast wall of water.

Great movie - shame about the science.

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I think you should have worked out by now, that science doesn't matter much in films.

Basically the explosions were McGuffins to explain what was happening to the Earth. The main plot is the Earth moving towards the sun.

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It's not "sci-fi", it's SF!

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Thanks for the tip. I quite agree. But they went to such effort in making this movie believable, it vexed me that so much of the obvious got overlooked. Still; the actual premise couldn't have happened anyway. Great movie even so!

Incidentally, I still prefer `sci-fi' as it distinguishes from `sci-fan' or science fantasy - which I suppose is what this movie actually was.

It's a pity that Val Guest et al didn't have a go at Wydham's `The Kraken Wakes' (a favourite of mine). Judging by this they'd have made an absolute cracker. Wyndham had already done the science homework for them.

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well they did say communications and radars were going out of order. and i think they tried to tell us that the atomic bomb was strong enough to actually move the earths core. the telescopes probably noticed the change, this wasont touched in the movie, it was neither confirmed or denied. as far as i know there are not many farmers in london, and this movie is set there. we had massive floods too, so water lag was accounted.
this movie is probably one of the most scientificaly correct ones in 60s, your simply asking too much of the times. they didnt knew half the things back then.

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All that is necessary for the triumph of evil is for enough good men to do nothing.

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It's troubling to me that so many people describe this movie as "realistic" or "scientifically correct". From the physics point of view, it's rather less realistic than a movie about an airplane flying to the moon.

To begin with, the largest nuclear blast ever (57 megatons TNT equivalent) is less than one trillionth of the kinetic energy of the earth's rotation. One bomb (or two simultaneous ones) will not have a measurable effect on how the earth spins.

If the earth's axis were suddenly shifted by 11 degrees, every object on the planet--already moving along with it at hundreds of miles per hour--would feel effects similar to what happens when a speeding car suddenly turns. Buildings would collapse; destruction would be everywhere. Anyone surviving this initial shock would be killed soon thereafter by a global tsunami.

For a solar eclipse to happen ten days early, the moon would have to be displaced by a third of a full orbit. Every astronomer on the planet--or anyone who reads the moonrise/moonset times printed in the newspaper--would notice this long before the eclipse. (By the way, no total solar eclipse observable in London occurred or will occur in the 19th through 21st centuries.)

The idea that nuclear blasts could cause the earth to fall into the sun is even more preposterous than thinking they could affect its rotation. It would be necessary to cancel nearly all of the earth's orbital energy, which is 10000 times as large as its rotational energy. It would take millions of hydrogen bombs per person to release that much energy.

Once again, a significant change in the earth's orbit could not be kept secret for weeks.

One point that the movie nearly got correct was Bill's estimate ("four months") of the time to earth's destruction. If the earth's orbital motion was cancelled, it would reach the sun in just over two months.

The basic physical fact is that nuclear weapons are not a danger to the integrity of the planet itself. Their threat is to the biosphere, and that primarily through their indirect effects (radiation, aerosols in the upper atmosphere) rather than their explosive energy.

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You dont need to cancel the earths rorational kinetic energy to make rotation change though. In a sense, the rotation we experience is rotation of earths crust. the inner parts are beleived to rotate faster, while the core is theorized to rotate at huge speeds (think hundreds of revs per second). In essens the crust is "floating". If you make a large enough impact and crack the crust (which, by the way, a third of our nuclear arsenal could do, no two seperate bombs of course, but say 300 blasts could). That will have a dual effect. For one weakened earth crust will give way to new volcanoes, espentially changign the flow of inner layer of eaths crust. it can also change the way the floatation works which may result even in such (albeit templorarely) things as earth spining from north to south (teplorary because physics will eventually put it back to nrmal rotation due to how erths core spins).
Another thing is we dont know squat about earths core. And it may decide to change its spinning one day and we could all die and never know why.
Another thing you forgot is Tsar Bomb - 200MegaTons. Though admitedly it is dismantled now and was never field-tested, does not mean that should the need arise we can build big bombs. also the technology has moved past the 60s now and we can make bombs that explode with more power (though we dont since that is pointless, modern warfare is about precision not big blast).

I said this was scientific compared to other 60s sci-fi movies. you know, those where a back alley doctor operates on his friend and saves his braisn in a jar which lives on for months on its own ir the ones where a half-man-half-fish comes from the sea due to people catching all his food - fishes.


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Applied Science? All science is applied. Eventually.

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Jules Verne played with a similar idea in "THE PURCHASE OF THE NORTH POLE", the 3rd book featuring "The Gun Club" (the other 2 being "FROM THE EARTH TO THE MOON" and "AROUND THE MOON").

In the novel, The Gun Club proposes building the biggest cannon ever seen on Earth-- a gigantic, monster-size shaft built deep in the ground somewhere in Africa. The idea is, by building such a weapon in the exact spot and angle, firing it will cause the Earth's axis to tilt at such an angle that all seasons will be eliminated, and people can then choose where on Earth they want to live depending on whatever perpetual weather will be there. (Totally INSANE!)

Keep in mind-- like the 2 previous books-- this was done AS A COMEDY!!!!! I read this in the late 60s when I was a kid, and it was one of the funniest things I ever plowed through.

In the long run, the idea doesn't work... and COULDN'T. The reasons for these, you'll have to read the book to find out. (I won't blow something like that for anybody!)

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