Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Orbital Motion
Name: Rocky
Status: student
Age: 15
Location: N/A
Country: N/A
Date: 2000-2001


Question:
When the planets orbit around the sun, the sun has a gravitational pull so they don't go flying off into space. With the power of the sun's gravitational pull, why don't the planets just come crashing into it?


Replies:
There is a nice balance between the direction change due to the gravitational attraction, and the motion of the object. Think of from events you know on earth. Go up on a mountain. Toss a rock. It lands a little bit down range. Now throw a rock. It goes further down range. Get a gun and shoot the rock. It goes further yet. Each second the rock was in the air, though, it was falling toward the earth, and the earth caught it. Now, what would happen if you threw the rock so hard, that it would fall at the same pace as the earth curves out from underneath it. It would fall the entire time, but instead of hitting the earth, it would just keep on missing it, and fall around the earth. That is the idea behind orbital motion.

Nathan A. Unterman



Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory