Kepler's 2nd Law: The Speeds of Planets
A diagram showing the path of a planet around the Sun.
Click on image for full size (9K GIF)
|
Kepler realized that the line connecting the planet and the Sun sweeps
out equal area in equal time. Look at the diagram to the left. What
Kepler found is that it takes the same amount of time for the blue
planet to go from A to B as it does to go from C to D. But the
distance from C to D is much larger than that from A to B. It has to
be so that the green regions have the same area. So the planet must
be moving faster between C and D than it is between A and B. This
means that when planets are near the Sun in their orbit, they move
faster than when they are further away.
Kepler's work led him to one more important discovery about
the distances of planets.
|
A table of orbital data for the planets
Kepler's 2nd Law: The Speeds of Planets
A diagram showing the path of a planet around the Sun.
Click on image for full size (9K GIF)
|
Kepler's second law he again discovered
by trial and error. Kepler realized that the line connecting the
planet and the Sun sweeps out equal area in equal time. Look at the
diagram to the left. What Kepler found is that it takes the same
amount of time for the blue planet to go from A to B as it does to go
from C to D. But the distance from C to D is much larger than that
from A to B. It has to be so that the green regions have the same
area. So the planet must be moving faster between C and D than it is
between A and B. This means that when planets are near the Sun in
their orbit, they move faster than when they are further away.
Kepler's work led him to one more important discovery about
the distances of planets.
|
A table of orbital data for the planets
Kepler's Second Law: The Speeds of Planets
A diagram showing the path of a planet around the Sun.
Click on image for full size (9K GIF)
|
Kepler's second law he again discovered
by trial and error. After some experimentation, Kepler realized that
the line connecting the planet and the Sun sweeps out equal area in
equal time. Look at the diagram to the left. What Kepler found is
that it takes the same amount of time for the blue planet to go from A
to B as it does to go from C to D. But the distance from C to D is
much larger than that from A to B. It has to be so that the green
regions have the same area. So the planet must be moving faster
between C and D than it is between A and B. This means that when
planets are near the Sun in their orbit, they move faster than when
they are further away.
Kepler's work led him to one more important discovery about
the distances of planets.
|
A table of orbital data for the planets
Last modified prior to September, 2000 by the Windows Team
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