Having read the book Friday by Robert Heinlein many years ago, I became aware of the concept of the space elevator/ space tethers. While fascinating in concept, our current technology negates the reality of this idea, however the physics involved are sound and it is a real possibility.

In the novel Friday, there were several colonies on multiple tethered space stations. To be honest, I don't remember mention of a gravitational effect on those stations. Was there gravity present from either mechanical means i.e. Star Trek-style "gravity generators" or from the Centrifugal action of the tether itself, or was it never actually stated, just implied?

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    The pictures weren't relevant to the question. I've removed them to make things a bit less cluttered.
    – Valorum
    Feb 11, 2015 at 14:27
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    Not the least confused just annoyed the we can't make side references to illustrate our topics. I'm not used to this very constrained format here. Feb 11, 2015 at 15:21
  • Realistically, if a station is on a tether it's not in free-fall (unless it's at at the radius of geosynchronous orbit or 42164 km, or about 6.6 times Earth's radius), so it will feel the Earth's own gravity, though it will be weaker depending on how its radius from the center of the Earth compares to the radius of the Earth's surface (if the station's radius is R times the radius of the Earth's surface, the gravity felt will be 1/R^2 times Earth surface gravity, minus centrifugal force v^2/r = 0.0034356 * R times earth's surface gravity).
    – Hypnosifl
    Feb 11, 2015 at 15:52
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    According to the Wikipedia page for Space Elevator (en.wikipedia.org/wiki/Space_elevator) > An Earth-based space elevator would consist of a cable with one end attached to the surface near the equator and the other end in space beyond geostationary orbit (35,800 km altitude). The competing forces of gravity, which is stronger at the lower end, and the outward/upward centrifugal force, which is stronger at the upper end, would result in the cable being held up, under tension, and stationary over a single position on Earth. Feb 11, 2015 at 19:26
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    Of course there's gravity. "Gotta get down on Friday," you know?
    – KSmarts
    Feb 11, 2015 at 20:25

1 Answer 1


Apparently they have artificial gravity in the Friday 'verse.

From chapter 27:

I dislike the Beanstalk [the space elevator] and I don’t care much for the twenty-four hour Station. Aside from its spectacular and always changing view of Earth it has nothing to offer but high prices and cramped quarters. Its artificial gravity surges uncomfortably and always seems to go out just in time to put soup in your face.

and chapter 30:

Did the (artificial) gravity feel steady now? I couldn’t be sure. I was quite dizzy but that might be an aftereffect of vomiting—for I had certainly thrown up as thoroughly as if I had been riding that goddam Beanstalk.

There are some other mentions of artificial gravity, but no need to be redundant.

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    Thank you @Joe L. It's been nearly 20 years since I read the book. Feb 11, 2015 at 15:24

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