Video of Earth spinning?

Question

If the Earth is spinning or rotating at a really fast speed, why haven't we seen any videos from space of it spinning when we get a lot of photos of it?

Answer 1

First of all, let's calculate the rotational velocity of the Earth, at the equator. The diameter of the earth is 12,756 km. Therefor, the speed is ${12,756km*\pi}/{24 hrs}=531.5 km/hr$.

Given that we know the rate of spin of the Earth, what else would be required to see this change?

1. The point of reference would need to be relative to the Sun, or possible the Earth-Sun system, but not LEO like most spacecraft are. Geosync. orbit would not work either, as the satellite is moving at the same speed as the Earth. A very high orbit might work, such as the Moon would be in.
2. In order to achieve 1, a significant distance from the Earth is required.
3. Given that a large distance is required, the Earth will not appear to be moving as quickly as it would otherwise.

Just to compare this, I pulled the speed of the moon orbiting the Earth from wikipedia. That speed is 1.022 km/s, or about 3680 km/hr. That is a much higher speed than the Earth rotational speed. Given that the distance requirements are similar to see the rotational speed of the Earth, it seems that one would have to notice the moon orbiting if one could notice the rotation of the Earth, in real time. (Note, it's a bit easier to see the Earth rotating, due to the easy comparison, but...)

Answer 2

Well it is quite expensive to go into space and so taking a video camera for some holiday snaps is not exactly a high priority.

However weather sattelites do exactly this with images of cloud formations and movements. Obviously these aren't typically very glamorous so rarely make into the public domain.

However they did recently take a camera on board the ISS

APOD sept 27 2011

rather pretty I think!

Answer 3

More importantly, in order to see the rotation properly, you'd need to stay at the same relative point in space. But in order to orbit the Earth, you typically need to go around it faster (until you get to geosynchronous orbit). The video's from the ISS make the Earth look like it's spinning because the ISS is orbiting so quickly. (It's mean orbital time is about 90 minutes.) I guess if the Apollo astronauts had taken a video recording of the Earth, from the moon for just over a day, you'd see about one full revolution of the Earth. But as said, that wasn't exactly a high priority: it's not like we're in any doubt that the Earth rotates once per day!

Answer 4

This video shows the Earth spinning at high speed, as seen out of the window of one of the space shuttles.