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A place to hang out and chat about astronomy

Wed Feb 07, 2018 12:24 pm

I was wondering if the space elevator ever was constructed would it be able lift very heavy objects off the earth.

As far as I know there comes a point far away from the earth where the earth's gravity is too weak to hold onto objects and the sun's gravity kicks in and begins to pull the object towards itself. If the space elevator cable was super long, could it be extended so far that it got affected by the sun's gravity and got pulled towards it. That way, a weight could be attached at the earth's surface to the cable, and be pulled up into space gradually.

Wed Feb 07, 2018 2:02 pm

al4 wrote:I was wondering if the space elevator ever was constructed would it be able lift very heavy objects off the earth.

As far as I know there comes a point far away from the earth where the earth's gravity is too weak to hold onto objects and the sun's gravity kicks in and begins to pull the object towards itself. If the space elevator cable was super long, could it be extended so far that it got affected by the sun's gravity and got pulled towards it. That way, a weight could be attached at the earth's surface to the cable, and be pulled up into space gradually.

One of the features of the Space Elevator is that the top is attached to something that has a 24 hour orbit. Otherwise, the top of the elevator would cause it to wrap around the earth due to the differential motion.
For it to extend consistently towards the Sun instead, we would have to stop the earth's motion, technically giving us a year long siderial day.

Wed Feb 07, 2018 8:37 pm

The geostationary orbit required for a space elevator can only be achieved at an altitude of about 35,786 km directly above the equator. The big question is can a cable of this length be manufactured that is light and strong enough not to break under its own weight. Lightning might be a problem too.
Google: Arthur C Clarke space elevator quote from The Fountains of Paradise.
This leads to a website full of ideas how the space elevator might work.
Incidentally, even at 35,786 km altitude above the surface, the Earth’s gravity field is approximately 0.224 m/s, about 37 times the 0.006 m/s Sun’s gravity field there.

Thu Feb 08, 2018 1:20 pm

Thanks for the replies. It looks like the sun gravity idea is too weak and far away to be useful. Perhaps cleaner burning fuels or rockets that run on solar generated electricity might be the future of getting cheaply into space.

Thu Apr 12, 2018 12:33 pm

al4 wrote:Thanks for the replies. It looks like the sun gravity idea is too weak and far away to be useful. Perhaps cleaner burning fuels or rockets that run on solar generated electricity might be the future of getting cheaply into space.

Fri Nov 09, 2018 10:47 am

good