Question about Lagrangian points in astronomy:

Originally posted by sonhouse
So 31850^2=~1E9/1.6E11 =~.006 meters/second^2, about 1/1600th of a G.

If the earth was not spinning, would we experience 1/16000th of a G downwards on the sun side of earth and 1/16000th of a G on the upward side of the earth?

What is your ring made of? Does it not exert its own gravity thus making the whole spin thing unnecessary? Or is it a thin shell with negligible mass?

Originally posted by twhitehead
If the earth was not spinning, would we experience 1/16000th of a G downwards on the sun side of earth and 1/16000th of a G on the upward side of the earth?

What is your ring made of? Does it not exert its own gravity thus making the whole spin thing unnecessary? Or is it a thin shell with negligible mass?

For this thought experiment I made the mass negligible. I think the Niven ring was like a million planets jammed together so the ring was like 12,000km deep or so giving a self gravity on both inner and outer surfaces. I just zero'd that out to look at the centripetal force isolated.

If you are advanced enough to pull that off, making it just rock 12K deep, that would be superior to spin artificial gravity since it doubles the available 1G surface area, clearly better than spin gravity since the outer surface could not support an atmosphere without a big cover or domes or such. It would be a much more natural place with self gravity on both surfaces, if indeed you could think of such a structure as natural🙂

I wonder just how many Earth mass planets would have to be melded together to make such a structure? It shouldn't be too hard to figure that one out. The Earth masses about 6 E24Kg, the sun masses about 2E30 Kg, about a third of a million earth masses.

It looks like (for a one planet sized ring) it would take 83 million Earths to do the job. That would be about 200 solar masses or about 4E32 Kg. Of course if you want a wider ring, not sure if gravity would even let you do that but a 24,000km wide ring would take 166 million such planets. A trivial feat for an advanced civilization, eh😉

Originally posted by twhitehead
If the earth was not spinning, would we experience 1/16000th of a G downwards on the sun side of earth and 1/16000th of a G on the upward side of the earth?

What is your ring made of? Does it not exert its own gravity thus making the whole spin thing unnecessary? Or is it a thin shell with negligible mass?

if it wasn't spinning would it collapse into denser mass, with the liquid parts gushing out the cracks?

Originally posted by zeeblebot
if it wasn't spinning would it collapse into denser mass, with the liquid parts gushing out the cracks?

If it wasn't spinning, that is to say turning in a manner as if a piece of it were a planet, there would be some force squeezing it but at only 1/6000 of a G in the case of our sun, it would result in a force easily capable of being supported by regular rock.

The one thing I saw, just got to talking about such a ring with my son Kevin, there would be no seasons for one, and Kevin suggested since one side would be fully illuminated and the other side permanently dark, there would be large permanent storms of wind going from sunlit to dark side.

That might be the case if the ring was toroid shaped. There would be no day/night cycle either. Life would be a lot different on such a place than Earth with seasons, day/night, tides, weather, etc.