What if a day were only slightly less than an hour?

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The earth spins around on its axis, and makes one complete turn every 24 hours.

That means that if you are standing at the Equator, you are moving at almost one thousand miles an hour even if you are "standing still".

If the earth made complete turns in only 55 minutes ( day and night day and night every fifty five minutes) a person at the equator would be moving at 25 thousand miles per hour.

That means that you would be moving at escape velocity. The speed NASA has to give to rockets to get them into interplanetary space.

In fact that is part of why NASA does it rocket thing in the tropical state of Florida: the proximity to the equator gives its rockets and extra boast due to the earth's spin.


So my question is this: what if the earth did spin at 25 times its present speed? Would folks in Quito Ecuador, and in Java, go flying off into space?

And would boulders and soil at the equator also go flying off into space?

Would the whole planet start to dismantle itself? The matter right at the equator would be ejected, making the whole planet progressively less massive, giving it progressively less gravitional pull, progressively reducing escape velocity, casuing stuff progressively farther from the equator to also go flying, and ..so on... until the whole planet disappeared?

I think it would depend on whether or not it had always been at the speed, or if we were to transition form our current spin speed to a speed 24 times faster.

If we started off at our current speed, then accelerated to 24 times the speed, you would definitely see some major disruptions (the extremity of which determined in large part by how quickly we transition to our new 24x speed).

If we had always been at that speed, then there wouldn't be things like sudden expulsions of mass into space, as the relative speed of everything else would remain the same. For example, you can stand up and walk around an an airplane traveling at 500 MPH faster than the earth is rotating, and experience little ill effect (so long as you do so after the plane has reached its new 'normal' speed). This is precisely the principle of relativity.

We would experience much more centripetal force, kind of like how they create artificial gravity on space stations by spinning them. Probably Earth it would be similar to a higher gravity planets if it had consistently been spinning 24 times faster than it does now for a long time.

As an aside, to achieve this new speed, there would need to be massive changes to the surrounding and internal physical bodies, as our rotational speed is determined by the angular momentum earth has had since creation, is influenced by gravitational forces, has been spun up faster by impacts, and is also influenced by the movements of earth's inner core.

there is a way to figure the centrifugal force but i don't have the math handy just now.

one time i actually re-did hal clement's calculations for his famous "mission of gravity" in which a solar day (on "mesklin") is less than 18 minutes long. i found the planet would start to lose mass at the equator & it would actually have to rotate less rapidly than that, in order to remain stable as a solid object.

When I read the title I thought this would be about the biological effects of living on a small planet with a 1-hour day-night cycle.

This question is less interesting to me. I don't know the answer but I do know that it is more complicated than the initial answers make out.

A simple answer is yes, if the Earth rotated at that speed we would be weightless. Spaceships can generate artificial gravity by rotating, but that's because you're inside the spaceship and being pushed out. The same effect occurs on Earth, but we are on the outside being pushed out. You are slightly lighter at the equator than at the poles.

There are more factors to consider though. Firstly, as graywyvern suggests, there are lots of implications for the planet itself. Secondly, "escape velocity" assumes no other forces act upon the object, but in this situation there would be considerable drag from the air. Thirdly, I'm sure there are a lot of relativistic considerations that I cannot properly get my head around. I know the escape velocity of the Earth depends on which way you fire your rocket - if you go against the Earth's rotation (as you always would) then it is about 25,000mph, but going with the Earth's rotation it is more like 26,000mph.

If the earth rotated on its axis fully in less than an hour.....there would be no life as we know it.

All the dirt, stones and air would also escape.
The planet would lose mass and the escaped things would likely form a ring, like those around Jupiter.
The planet would shrink until the velocity on the equator (which is proportional to radius in a rotating rigid object) became lower than orbital velocity. However, that would make the planet lighter, making the orbital velocity lower, too.
I could probably calculate it for a uniform planets but you know that planets aren't uniform. The dense, metallic core would remain.
We would end up with a lot smaller planet with rings. No atmosphere and no water, gases would escape the first and light fluids would quickly follow. New moons may form from debris in the rings.


If you want a specialist to do the Math thoroughly for you, you can submit it for XKCD What If: https://what-if.xkcd.com/ . Randall seems to love this kind of questions.

Glad to read this informative discussions. Thanks all