Chapter 11 - Exploring Forces
Did it all start when an apple bopped Isaac Newton on the head? This activity explores some of the ways his fundamental laws are expressed in our dynamic solar system.
Could a space rock destroy life on Earth? Learn more about asteroids, comets, and other space objects and what happens when they collide—with each other and with our planet.
Who said daydreams are a waste of time? One of Einstein's flights of fancy led to the equivalence principle—the knowledge that while an object is in free fall, it's free of gravity's effects.
Gravity may seem elementary. But proving Einstein's theories about it is quite hard. To do so, scientists are struggling to capture gravity's most elusive hallmark: the gravitational wave. This Astro Feature focuses on research at the Laser Interferometer Gravitational-Wave Observatory (LIGO) in Livingston, LA, where scientists have constructed a sprawling facility dedicated to the detection of minute changes in spacetime caused by gravitational waves traveling from energetic events in space.
Did you know that satellites and the Space Shuttle don't need engines to power their orbits? See how Earth's gravitational pull bends their forward motion and keeps them moving around the planet.
Peer at the world through the eyes of Einstein—a scientist who saw a beam of light and imagined riding it, a self-proclaimed "citizen of the world" who spoke out on global issues from pacifism to racism.
November 15, 2002 - January 1, 2003