# The Naked Scientists Forum

### Author Topic: tapping the earths angular momentum  (Read 2465 times)

#### thebrain13

• Sr. Member
• Posts: 442
##### tapping the earths angular momentum
« on: 21/11/2007 01:53:33 »
We launch many rockets into outerspace. Each rocket has miles and miles of strong cable onboard. The cable is then released and connected to each other and connected to earth, preferably near the equator. The cable is so long that the force of gravity is not strong enough to pull the whole cable down to the earth, since the cable far away from earth has enough centrifugal force to pull the cable near the surface of the earth upwards. So essentially what we have is a cable connected near the equator, that is standing straight up all by itself.

Once we got a freestanding cable constructed, this would allow alot of major advantages. Two specific things come to mind. It allows us to move things mechanically into outer space, that would be a million times more efficient than blasting an object out of the earths pull using rocket fuel. Another major advantage is energy production. once we got a freestanding cable up we could send little vehicles up, that could climb the cable, make it longer and stronger. We could then start building a conveyor belt type system. The system would have a long and very strong cable, that would connect to create a giant oval type shape. Once the conveyor belt system was in place, we could get it to flow by attaching things to the cable. Since the centrifugal force near the top is stronger than the gravity near the bottom. By attaching things to the belt on the bottom and releasing them once they reach the top, it would create energy.

Note this is not a perpetual motion device because the energy used to lift the objects off the ground is made up for by using the earths angular momentum, it would slow the earth down over time. Once the objects were released near the top it would flow away from earth, because its momentum is too great to be caught by the earths gravitational force again, it wouldnt be in orbit thus it wouldnt create space garbage.

So once we got the conveyor belt system in place we could move anything we wanted to in outer space just by attaching it to the upward moving side of the cable. We could create energy using whatever we wanted, dirt, rocks, water (since the earth is gonna flood) or rocket ships and people. We could even run materials up and build another system on mars or whatever planet we wanted to travel too.

#### Soul Surfer

• Neilep Level Member
• Posts: 3345
• keep banging the rocks together
##### tapping the earths angular momentum
« Reply #1 on: 21/11/2007 23:10:19 »
The concept of the space elevator is a great one and could work in theory the main problem for the earth is one of strength to weight ratio of the materials involved in its construction.  Conventional materials like high tensile steel are just too weak.  It has been suggested that carbon nanotube fibres could just about be strong enough and light enough to work for an earth based space elevator but they would be very marginal and the results of failute could be spectacularly catastrophic.  Of course that assumes that the mateials required are available in sufficient quantity.

#### thebrain13

• Sr. Member
• Posts: 442
##### tapping the earths angular momentum
« Reply #2 on: 22/11/2007 00:05:09 »
Breaking would be a major problem. If it broke somewhere in the middle, the top would go flying off into outerspace, and the bottom would come crashing down to the ground. It would make an excellent terrorist target.

I did some searches, my idea isnt so original afterall. Oh well I figured it wasn't. Nasa, I hear is coming up with designs to build one, and they may attempt construction as early as the end of the decade. However I have some critiques on their design. One thing comes to mind is that, why have a cable with one diameter the whole way? they were anticipating using a 4 inch cable made of carbon nanotubes, but If you think about it, the greatest amount of tension on the cable is in the very middle, or the place where gravity equals the centripetal force. Why not make that section of the cable thicker and stronger, because it doesnt matter much if you make that section of the cable heavier because there is not much net force (gravity vs. centripetal) so it would not contribute as much to the overall tension of the entire cable. They also didnt mention my energy production/method for lifting stuff up the cable.

#### The Naked Scientists Forum

##### tapping the earths angular momentum
« Reply #2 on: 22/11/2007 00:05:09 »