Re: Space Shuttle Lifting Off

What happens when you throw a rock straight up? It comes right back down. So would the Space Shuttle, if it went straight up. The Shuttle isn't powerful enough to escape the pull of Earth's gravity.

So how does it stay up in space? The answer is given in one of the most famous diagrams in physics, drawn by Isaac Newton. Imagine a tall mountain (V) on the Earth, which sticks up above the atmosphere. There's a cannon on the mountaintop which shoots cannonballs horizontally at various speeds. Slow cannonballs (D) land right next to the mountain; faster ones (E) land farther away. For even faster cannonballs (F), the round Earth curves away from the path of the cannonball. For very fast cannonballs (B), the Earth curves enough that the cannonball never hits the ground at all! Instead, the cannonball makes a complete "orbit" around the Earth. The cannonball is constantly falling, but the Earth curves more than the ball's path does.

There's a very cool Java applet which will let you play with launching cannonballs from Newton's mountain at various speeds.

The Space Shuttle orbits just like the cannonball, "falling" constantly around the Earth but always missing the ground. The Space Shuttle's main job is not to go high, but to go fast. It needs to pick up a huge amount of horizontal speed (about 8 kilometers per second) to avoid hitting the ground. To do so, it curves over from a vertical launch position to a horizontal path as it leaves the launch area, firing its engines horizontally.

This is kind of difficult to notice from the close-up photos you usually see on television of a shuttle launch. I see you're in Florida; maybe you've seen a launch in person, where I'd expect the curving path is much more obvious.