Sciency Words: Clarke Orbit

Welcome to another episode of Sciency Words, a special series here on Planet Pailly where we take a closer look at the defintions and etymologies of science or science-related terms so we can expand our scientific vocabularies together.  Today’s term is:


So I was once again flipping through my copy of Brave New Words: The Oxford Dictionary of Science Fiction when I discovered a small fact that gave me a big surprise.  It involved Arthur C. Clarke, the legendary science fiction writer who’s best known for co-writing the screenplay of 2001: A Space Odyssey, but who was also a prominent thinker, futurist, and inventor.

In 1945, Clarke wrote this article for Wireless World describing a method for transmitting radio and television signals to the entire globe.  Clarke’s idea involved placing artificial satellites in a very specific and somewhat peculiar orbital arrangement.  Clarke explains:

It will be observed that one orbit, with a radius of 42,000 km, has a period of exactly 24 hours.  A body in such an orbit, if its plane coincides with that of the equator, would revolve with the earth and would thus be stationary above the same spot on the planet.

Clarke admits that this idea may sound a little too fantastical to some, but he argues that it’s entirely plausible to do this using current (as of 1945) technology.  His only concern was whether or not radio transmissions would be able to penetrate Earth’s ionosphere, though he was confident that at least some radio frequencies would work.

And of course Arthur C. Clarke was right (he usually was about these sorts of things).  We now know this orbital arrangement as a geosynchronous orbit, or to be more specific a geostationary orbit.  A geosynchronous orbit allows a satellite to move around in Earth’s sky, so long as it always returns to the same positions at the same times of day. A geostationary orbit does not allow a satellite to move at all in Earth’s sky.

And according to Brave New Words, these kinds of orbits are also known as Clarke orbits.

So which term should we be using?  Personally, I’m not sure.  I like how the term Clarke orbit honors Arthur C. Clarke for inventing the idea.  On the other hand, I appreciate how the term geostationary orbit helps define itself, thus making verbal communication a little easier.

So which of these terms would you prefer? Clarke orbit or geostationary orbit?

8 thoughts on “Sciency Words: Clarke Orbit

  1. I think we should say “Clarke geostationary orbit”, the same way we say “Hohmann transfer orbit”. Granted, there are other types of transfer orbits, which might be why Hohmann get’s his name in one but Clarke typically doesn’t.

    Liked by 1 person

    1. That seems like a nice compromise. Or maybe we could go with “Clarke geosynchronous orbit,” since there are lots of possible geosynchronous orbits but Clarke specifically described the kind that lines up with Earth’s equator.

      Liked by 1 person

  2. I like both, like you, for different reasons. On a side note, I have an old issue of Analog from the late 70s/early 80s with an editorial by Clarke in which he predicted that by the 2000s or so we’d all be communicating with people across the globe with briefcase-sized portable computers. Wasn’t too far off from describing smartphones.

    Liked by 2 people

    1. I’d say check out that article by Clarke. He does a pretty good job explaining it in plain (if somewhat antiquated) English.

      Or you could check out this video. It’s a tutorial for the video game Kerbal Space Program, but the guy does a really good job demonstrating how a spacecraft can get to a geostationary Clarke orbit.


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