In case you haven't been through the comments, Andy posted a super-cool article about the increasing feasibility of a "space elevator". Gravity holds it down to earth on one end, and the rotation of the earth keeps it out on the other end*. The only problem was having an appropriate structure to balance those forces.
Well, that and the actually doing it part. Anyway, check it out.
*Geeky Physics Note below (BEWARE)
Note: Notice how much effort I went through to *not* use the word "centrifugal"? Physics geeks should note that the article got this wrong. While they didn't use the highly vexing phrase "Centrifugal Force", they nonetheless described "outward centripetal force", which is nonesense, considering centripetal is defined as inward (litereally, center-seeking). Here is a pretty good article discussing the distinction. What is really happening is that the rotation of earth is applying force both along the edge of the rotation (straight-line) and toward the center (centripetal straight line) which is what keeps it going in a roughly circular orbit instead of falling back to earth or shooting off. The cable balances these forces, keeping it rotating. From the reference of Earth this looks like its being pulled outward, but really, its just moving in a circle.
This is a highly disturbing misconception for physicists. Equally troubling is the common assertion of "zero-gravity" while in orbit. What is actually happening is zero-weight, due to the constant falling of orbital motion. For a body to feel weight, there has to be something pushing against the force of gravity. In the case of everyone reading this, that something is the surface of the Earth. But in orbit, there is nothing pushing back, the body is experiencing all of the acceleration of gravity as motion. So there is no weight felt. This is the same phenomenon noticed in a quick moving elevator.
In fact, at the height of the rocket launch on Monday (62 miles) the force of gravity was only 3% less** than at the surface. The reason you saw the M&Ms floating was weightlessness, not zero-gravity.
**Radius of Earth^2 / (Radius of Earth + 62 miles)^2 [Calculated with Google]
