Question about space elevators:

When we have built that polar tower to connect Earth to Moon, and unwound the cabel - how would it look like?

Would it be straight as a line, or would it sag in the influence of the gravitation?

As it will start at the top of the tower, well over the atmosphere, will the cable sage down through the atmosphere before it raise again, or do we need to build the tower much higher that proposed, just to avoid the atmospheric touching?

The cable will have to be attached to the tower with some force, and at the moon with some force. Is this forces enough to change the orbital parameters of this double body system? Will the Earth axis tilt be different during the years, decennia, centuries to come?

When using this cable to transport gods and people - will it go through the van Allen belts? Do we need to have to take precautions for a safe trip? How much is needed?

Originally posted by FabianFnas

When using this cable to transport gods and people - will it go through the van Allen belts?

Surely gods can transport themselves without use of cables. 😉

Originally posted by Soothfast
Surely gods can transport themselves without use of cables. 😉

They need cables otherwise why would we have Deus Ex Machina.

Originally posted by Soothfast
Surely gods can transport themselves without use of cables. 😉

Oh, is the word goods? Sorry... ;-)

Originally posted by FabianFnas
Oh, is the word goods? Sorry... ;-)

Good of you to figure that out🙂

As for the cable, if you had a tower high enough to allow visibility to the moon 24/7, the cable would be attracted to Earth so it would bend down to Earth some and then when it got to the moon, it would be attracted to the moon so THAT would bend it some into the moon so the cable would be in the shape of a weird parabola, wouldn't be in a straight line. And if they were to connect, the moon moves closer and further to Earth by around 30,000 kilometers or so, a strict cable would not be able to withstand such stretching I would assume, that would be a stretching of about 10 percent of it's length. So i assume in that case a cable winding and unwinding spindle would have to be employed for the slow changing length of the cable. That is why I thought it could generate power, using that changing cable length to power a generator.

Just force the Moon into a new orbit that is exactly geostationary, circular and with a orbital plain tilted that is exactly the same tilt of that of the plain of rotation of the Earth spin on its own axes. Then you can make a space elevator that goes directly from the Earths equator to the Moon.
Simple!

Originally posted by humy
Just force the Moon into a new orbit that is exactly geostationary, circular and with a orbital plain tilted that is exactly the same tilt of that of the plain of rotation of the Earth spin on its own axes. Then you can make a space elevator that goes directly from the Earths equator to the Moon.
Simple!

With moon at a geostationary orbit...

Good bye to all stable satellite orbits.

Any more interesting effects?

Would the shorelines be different from now? How about earthquakes when the Moon moving maneuvers are being made? Would there be any biological effects when we don't have any moving moon on the sky, half the earth wouldn't have any moon at all, while the other half always have a moon on the same spot in the sky? Would there be any atmospheric disturbances with a cabel (or many) going through the atmosphere?

Originally posted by humy
Just force the Moon into a new orbit that is exactly geostationary, circular and with a orbital plain tilted that is exactly the same tilt of that of the plain of rotation of the Earth spin on its own axes. Then you can make a space elevator that goes directly from the Earths equator to the Moon.
Simple!

Yes, except for the minor technical difficulties associated with tides being several orders of magnitude larger.

Edit - of course, the tides would also be stationary so the earth would be effectively tidally locked to the moon.

Originally posted by DeepThought
Yes, except for the minor technical difficulties associated with tides being several orders of magnitude larger.

Edit - of course, the tides would also be stationary so the earth would be effectively tidally locked to the moon.

I think that's how the moon started out, like all the debris collected around 20,000 miles out and has been receding for the past 4 billion odd years. I wonder if the moon could work loose completely from Earth given enough time? It is receding at about 2 cm per year or so, could it escape completely?

Originally posted by sonhouse
I think that's how the moon started out, like all the debris collected around 20,000 miles out and has been receding for the past 4 billion odd years. I wonder if the moon could work loose completely from Earth given enough time? It is receding at about 2 cm per year or so, could it escape completely?

No, it will not leave Earth. It outward motion will halt when the two bodies are syncronized with eachother. Then it will spiral back to earth and eventually bu cruched by tidal (!) forces and form a ring of debris around the Earth, like Saturns ring. This will happen in the far future.

Originally posted by FabianFnas
No, it will not leave Earth. It outward motion will halt when the two bodies are syncronized with eachother. Then it will spiral back to earth and eventually bu cruched by tidal (!) forces and form a ring of debris around the Earth, like Saturns ring. This will happen in the far future.

Considering it has already taken several billion years to get to where it is now, both Earth and the moon will be cinders when they are included inside the atmosphere of the sun which is due to expand to a size greater than Earth's orbit so the rings will happen alright, but Earth won't be around to enjoy them🙂

I will go out on a limb and say the human race will be way extinct by that time anyway so we won't have to worry about it since the time frame for all that is several billion years in the future.

It is still mind boggling to think the sun will expand that far and Mercury will be the first to go, then Venus, then Earth/moon, then Mars.

I have a tentative sci fi plot where some future genetics engineers make a time capsule kind of thing and sprinkle all that nanotech on Encaledus, Europa and such, the ice moons and the idea is when the Earth is destroyed the sun will start melting the ice on those moons and the a reaction takes place that activates the nanotech to rebuild a human civilization, first collecting materials to build more complex machines then build environmental chambers that can hold human DNA and thousands of other Earthy life forms and rebuild all those life forms and at first the first generation of humans is brought up by robots but the succeeding generations are brought up by humans and they go about reseeding all the other life forms, plants, insects, carnivores, prey animals and so forth to build a new ecology and to build space craft to get out of dodge and rebuild on a better planet. Of course there is all the information that science had gleaned from the vantage point of Earth a couple hundred years from now. All that engineering knowledge and such encoded into the nanotech, ready to be used when humans are grown and are taught all that knowledge and the history of the then ancient Earth.

I think that is an awesome concept.

Originally posted by sonhouse
Considering it has already taken several billion years to get to where it is now, both Earth and the moon will be cinders when they are included inside the atmosphere of the sun which is due to expand to a size greater than Earth's orbit so the rings will happen alright, but Earth won't be around to enjoy them🙂

I will go out on a limb and say the human ...[text shortened]... that knowledge and the history of the then ancient Earth.

I think that is an awesome concept.

Get hold of a book by Stephen Baxter - Evolution. Really awesome stuff on the evolution of the earth, humans, and their final demise.

Originally posted by sonhouse
Considering it has already taken several billion years to get to where it is now, both Earth and the moon will be cinders when they are included inside the atmosphere of the sun which is due to expand to a size greater than Earth's orbit so the rings will happen alright, but Earth won't be around to enjoy them🙂

I will go out on a limb and say the human ...[text shortened]... that knowledge and the history of the then ancient Earth.

I think that is an awesome concept.

I will go out on a limb and say the human race will be way extinct by that time

Unlikely that we would be extinct even then. By then we would have spread and colonized many other solar systems thus any disaster that wipes out all the human colonies on any one planet would not wipe out humanity and it would take many independent fatal disasters to happen on many planets more or less simultaneously to wipe out humanity and that would be a pretty absurd coincidence!

The only two credible way humanity could go extinct once humans start putting permanent human colonies on other planets (asp in other solar systems ) is if either humanity eventually evolves into one or more other non-human species that eventually displace all humans or humans go extinct because of the entropy in the universe eventually rubbing all life of sufficient amounts of usable energy but, in either case, that would take a very long time.

Originally posted by humy

I will go out on a limb and say the human race will be way extinct by that time

Unlikely that we would be extinct even then. By then we would have spread and colonized many other solar systems thus any disaster that wipes out all the human colonies on any one planet would not wipe out humanity and it would take many independ ...[text shortened]... fe of sufficient amounts of usable energy but, in either case, that would take a very long time.

You do realise that the estimated time to reach Alpha Centauri is of the order of 40,000 years? Unless the speed of light turns out not to be the great barrier we currently think it is the prospects of colonising planets around other stars are about nil.

Besides, if the planets are habitable then the chances are they'll already be occupied and if they aren't then terraforming isn't a trivial exercise.

Originally posted by DeepThought
You do realise that the estimated time to reach Alpha Centauri is of the order of 40,000 years? Unless the speed of light turns out not to be the great barrier we currently think it is the prospects of colonising planets around other stars are about nil.

Besides, if the planets are habitable then the chances are they'll already be occupied and if they aren't then terraforming isn't a trivial exercise.

AC is only about 4 light years away. So taking 40,000 years puts the velocity at 1/10,000 c. That is about 32 kilometers per second. I would say we can reach at least 0.1c which puts AC 'only' 40 years journey. 0.2c, 20 years.
0.4c, 10 years and so forth. I don't think it will be a huge engineering problem to reach 1/10th c. For this century maybe but eventually there will be fusion reactors in space far outstripping any chemical fuel rocket. You will be dealing with specific impulse ratings of 10,000 or more.

That's not even looking at the various laser schemes afoot, 600 mile wide lenses at the distance of Neptune and such with gigawatt lasers driving some kind of spacecraft. That scheme uses little fuel so it would be inherently more efficient in terms of what can be achieved with any kind of rocket, even fusion.