Is it true that when you are in outer space observing, it would take less than 24 hours for earth to rotate?

Question

Let say you are in space and time 1 full rotation of the earth, is it true that it is less than 24 hours? If so, it would take less time in space to wait for a day on earth

Answer 1

The Hafele-Keating experiment that proved that Einstein's theory of relativity was true, put atomic clocks on airplanes that went around the world, with one going in each direction. The one traveling westward gained 237 nanoseconds because its velocity moving through space was slower than that of the clock on the surface of the earth, which by the way is traveling left to right.

Let's break this down.

First, imagine the earth from space, spinning left to right and moving around the sun in a counter clockwise direction. You are the moon, traveling with the earth, slowly rotating around it. Since the moon takes 28 days to orbit the earth, you can put yourself on the moon for this experiment.
You talk into our radio and say "GO!" and you and your buddy on earth both click your stop watches. Then you say "talk to you tomorrow" and thrust away to go look at some big craters. 23 hours later, you can see the North American continent comming up on the horizon and you establish radio communications with your buddy again. You say "STOP!" and you both click on your watches, and they are both identical in their measurement of the passing of time. 23 hours 12 minutes 36 seconds.

"What the heck! I thought you said..."

Know what a nanoseond is?
one second = 1
one centisecond = .01
one millisecond = .001
one microsecond = .000001
one nanosecond = .000000001
In the experiment, the clock that traveled westward around the earth gained 237 nanoseconds.
237 nanoseconds = .000000237

Your typical stop watch measures down to hundredths of seconds. These are called centi-seconds.
one centisecond = .01

Therefore the amount of time difference will be unmeasurable by the typical non-university student with readily available time pieces. (and uncalibrated thumbs)

I would like to see a much more dramatic measuement of the passage of time.
Our galaxy is moving through space (we think), our solar system is moving in our galaxy, our earth is moving around our sun and the surface of the earth is rotating on its axis. That's alot of velocity.
We could take a probe and send along the path of the earth ahead of the earth/sun/galactic movement, and then using retro rockets cause it to achieve a stationary position, waiting for the earth/sun/galaxy to catch up to it. That would be the one way to eliminate the effect of velocity on the mass of the probe.

I am curious to know how much time we are all losing hurtling through space.

:-)

Answer 2

Yes and No. A solar day is exactly 24 hours long but a siderial day is 23 hours, 56 minutes and 4 seconds long. To measure a solar day, wait until the sun is at it's highest in the sky and start a timer. Then next time it is highest in the sky, stop the timer. The timer will read, on average, 24 hours. Now pick a star and do the same thing. The result will be 23h 56m 4s. Why the difference? Because the Earth completes 1/365 of an orbit in a day, so it has to turn an extra 1/365 of the way around before the Sun comes back to the same place in the sky. And why did I say, "on average"? Because the Earth's orbit is elliptical. It orbits a little faster when it is closer to the Sun and a little slower when it is farther from the Sun.

Answer 3

RL612 gives a good first part of the answer.

There are two different "days" to talk about. One of these is called the sidereal day. This is the time it takes for the earth to rotate 360 degrees and is slightly less than 24 hours. However, during this time the earth has traveled almost 1 degree around the sun. For the sun to appear in the same part of the sky as the day before, it must rotate slightly more than 360 degrees and so it takes a slightly longer amount of time which is the 24 hours that we associate with the "normal" or synodial day. This is all based on the "frame" from which we are observing some phenomena.

This is not theoretical, it is real and has been measured. It is a "simple" math problem, just that we don't regularly look at these different problems in school. As we apply math to "the real world" we see a need to expand our minds and usage to include variables that change with time. Good luck with your astronomy questions!

Answer 4

there is a difference in the definition of 1 rotation and 1 day. A day is the time it takes a point on the earth to be under the sun (i.e. sun directly overhead, or directly south, etc. until the same alignment occurs the following day. this takes 24 hours. However, the earth has moved almost 1 degree around the sun, so it has had to over-rotate by about 1 degree to get the sun directly over the same spot again. When I say 1 degree (about) it is because there are 360 degrees in the orbit, but, 365.25 days per year so the earth travels 360/265.25 degrees per day.

This means that a "day" is a real rotation of the earth of about 360 degrees + this almost one more degree. So it would have taken less time to actually only rotate 360 degrees. This could be observed, theoretically by being outside the earth, but, you would need to have some frame of reference, like some star system to align yourself with.

Answer 5

It isn't exactly 24 hrs. long,but almost. If you were on a space shuttle it would still be the same. But,time really does slow down if traveling at very high velocities. Atomic clocks have already proven that.

Answer 6

On the space staion a "day" lasts a mere 90 minutes if you're using sunrise and sunset as your clock. Wouldn't it be nice if you could go to space for 180 minutes and come back 2 days later.

Answer 7

I would say no.