{"id":15709,"date":"2025-06-28T06:35:49","date_gmt":"2025-06-28T06:35:49","guid":{"rendered":"https:\/\/topat10.com\/?p=15709"},"modified":"2025-06-28T06:35:49","modified_gmt":"2025-06-28T06:35:49","slug":"space-elevators-could-totally-work-if-earth-days-were-much-shorter","status":"publish","type":"post","link":"https:\/\/topat10.com\/?p=15709","title":{"rendered":"Space Elevators Could Totally Work\u2014if Earth Days Were Much Shorter"},"content":{"rendered":"


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Suppose you could<\/span> speed up Earth\u2019s rotation so that a day was only half as long? What would happen? Well, for starters we\u2019d have to make new clocks that only have hours 1 to 6 for am and pm. If you had tickets to an 8 o\u2019clock concert, you\u2019d be out of luck: 8 o\u2019clock no longer exists.<\/p>\n

But maybe a more germane question is, why do physicists ask nutty questions like this? It\u2019s never going to happen\u2014just move on, right? Well, here\u2019s the deal. Thinking about counterfactual scenarios gives us insight into how things work here in reality. Plus, it\u2019s fun! Need I say more? OK, it might even help us build a working space elevator.<\/p>\n

Oh, you don\u2019t know what a space elevator is? It\u2019s a sci-fi staple, a tether from Earth up to an orbiting space station in geosynchronous orbit. A cable-climbing car would ride up and down, just like a regular elevator. Basically it\u2019s a way of getting out to space as easily and routinely as you ride an elevator to your office in the morning\u2014no rockets required.<\/p>\n

Let’s start off with some basic questions and build up to some more complicated physics.<\/p>\n

What Is a Day?<\/h2>\n

You can\u2019t get more basic than that. But the answer isn\u2019t simple. If you said a day is 24 hours, you\u2019re right\u2014and wrong. If you\u2019re standing outside, the time at which the sun is at its highest point in the sky is called local noon. If you stand there until the next local noon, the amount of elapsed time is defined as 24 hours. So an hour is 1\/24th of the time between two local noons.<\/p>\n

But wait! This isn\u2019t the same as a complete revolution of the Earth. If you measured the time of a complete revolution, you\u2019d find that it\u2019s not<\/em> exactly 24 hours. The reason is that the Earth is doing two things at once: It’s spinning on its axis, which causes the sun to appear to move across the sky. But it’s also orbiting the sun over the course of a year, which means a complete rotation will not result in the sun being in the same position in the sky.<\/p>\n

There are actually two different types of days. The solar day<\/em> is the one you are thinking of, and it\u2019s the one described above. The other type is called a sidereal day<\/em>. Here’s a totally not-to-scale diagram that will help you understand the difference:<\/p>\n

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