Satellite orbits
One of the most surprising things about satellites is the very different paths
they
follow at very different heights above Earth. Left to its own devices, a satellite
fired into space might fall back to Earth just like a stone tossed into the air. To
stop that happening, satellites have to keep moving all the time so, even though
th
e force of gravity is pulling on them, they never actually crash back to Earth.
Some turn at the same rotational rate as Earth so they're effectively fixed in one
position above our heads; others go much faster. Although there are many
different types of s
atellite orbits, they come in three basic varieties, low, medium,
and high
—
which are short, medium, and long distances above Earth, respectively