The universe is mostly
empty space. Even in a "crowded"
region like our solar system, the distances
between planets are so vast that they are
difficult to imagine. This animation simulates
a voyage from the sun past all nine planets.
For convenience, the planets are lined up
in the same direction. The animation shows
each planet's average distance from the
At the speed of today's fastest spacecraft
(~20 km/second), it would take almost ten
years to travel this distance. Even at the
speed of light, the trip would last 5 1/2
hours. In this animation, the apparent speed
of the viewer is over 300 times the speed