Same for the ISS…it looks like it’s standing still but it’s actually moving. Why is that?
In: 0
It comes down to a question of linear speed versus angular speed. The linear speed of the Earth’s rotation is some 1670 km/h: over a thousand miles per hour. This seems quite fast, and it is. But the Earth is so big that it takes 24 hours to complete a single revolution, and in terms of angular speed that’s actually very slow.
The hands on a clock are a very good analogy. It’s very hard to see the minute hand on a clock moving unless you’re up very close, and it spins 24 times a day. The hour hand moves one-twelfth as fast as this, spinning twice a day, and it’s basically impossible to see moving without a microscope. And the Earth is only half as fast as that.
The ISS, as some have noted, is faster, taking some 90 minutes to orbit the Earth. But this is still about a third slower than the minute hand on a clock, which is already very hard to catch moving. So it’s harder to catch the Earth spinning under the ISS than it is to catch that minute hand spinning.
Latest Answers