What is Kelpers law of planetary motion?

Answer 1

• The path of the planets about the sun is elliptical in shape, with the center of the sun being located at one focus. (The Law of Ellipses)
• An imaginary line drawn from the center of the sun to the center of the planet will sweep out equal areas in equal intervals of time. (The Law of Equal Areas)
• The ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the sun. (The Law of Harmonies)

Answer 2

First law: [The orbit of every planet is an ellipse with the Sun at one of the two foci.]

Kepler discovered that Mars did not move in a circle around the sun, but moved in a slightly elongated ellipse. An ellipse is a closed curve in which the sum of the distances from the edge of the curve to two points inside the ellipse is always the same.

Second law: [A line joining a planet and the Sun sweeps out equal areas during equal intervals of time.]

Kepler discovered that the planets seemed to move faster when they are closer to the sun and slower when they are farther away.

Third law: [The square of the orbital period of a planet is directly proportional to the cube of the semi major axis of its orbit.]

Kepler noticed that planets that are more distant from the sun as Saturn, take longer to orbit the sun. This explains the relationship between the period of a planet's revolution and its semi major axis. Knowing how long a planet takes to orbit the sun, Kepler was able to calculate the planet's distance from the sun.

See related link for more information.

Answer 3

Kepler's "Laws" of planetary motion:

-- The planets move in orbits that are ellipses, each with the sun at one focus.

-- The square of a planet's orbital period is proportional to the cube of its distance

from the sun. That is

T2/R3

is the same number for every body gravitationally bound to the sun, and the

orbital period only depends on the shape and size of the orbit, not on the mass

of the orbiting body.

-- The radius vector from the sun to the planet sweeps out equal areas in equal amounts

of time. This means that any object in a gravitational orbit moves fastest when it's closest

to the sun, and slowest when it's farthest from the sun.

Kepler derived these laws from Tycho Brahe's observations, after Tycho had kept

records of where the planets were seen each night during a large part of his life.

Later, Newton came along. Writing his law of universal gravity and using calculus

and geometry to massage it and figure out how bodies in gravitational orbits would

behave, he showed that his law of gravity directly predicted Kepler's Laws.

Answer 4

Kepler's "laws" of planetary motion are 3 in number:

1). The orbits of the planets are ellipses, with the sun at one focus of each.

2). The radius vector (the line from the sun to the planet) sweeps out equal areas

in equal time intervals.

(This says that the planet must be going faster when it's nearer the sun, and slower

when it's farther from the sun.)

3). The square of the planet's orbital period is inversely proportional to the cube of the

semi-major axis of its orbital ellipse.

(This says that for all planets around the same sun, the relationship between

the planet's distance from the sun and its 'year' is the same number, so if you

know one of those things about a planet, you can calculate the other one. It

also says that the farther a planet is from the sun, the longer its 'year' is, not

only because it has farther to go, but also because it moves slower in its orbit.)

The really amazing thing about these laws is the way that Kepler figured them

out: He started with the notebooks of Tycho Brahe, who had spent most of his

life looking at the planets every clear night, measuring their positions, and

keeping written records of his measurements. Kepler had these records, and

spent years of HIS life trying to come up with rules that could explain the

motions that Tycho actully saw. Remember . . . . this was at a time when the

answer to whether the planets revolve around the Earth or the sun was not

even really nailed down yet. Kepler just tried one set of rules after another,

until he came up with the three rules listed above, and he showed how

beautifully they explain every move we see the planets make.

But even THAT isn't the real punchline! The part that's even more amazing is how

Isaac newton ... born in the year that Galileo died, and 12 years after the death

of Kepler ... developed the whole concept of the nature of gravity, which is so

profound that this formula tells you everything there is to know about it:

F = G m1m2/R2and then Newton invented Calculus, and then he took his formula for gravity,

and he massaged it with calculus and geometry, and he showed why the planets

MUST follow Kepler's three laws.

Answer 5

Johannes Kepler (1571 - 1630) using the astronomical data collected by Tycho Brahe concluded the 3 laws of planetary motion.

1) The orbit of every planet moves in an ellipse with the sun at one focus.

See Kepler's first law diagram on wikipedia in related links.

2) A line joining the planet and the sun sweeps out the same area for equal periods of time.

As the planet orbits it is moving fastest when it is closest to the sun and slowest when it is furthest from the sun.

See Kepler's Second law diagram on wikipedia in related links.

3) The square of the orbitil period of the planet is directly proportional to the cube of the semi major axis of it's orbit.

The further the planet is from the sun so proportionally the longer its orbital period. e.g. a planet twice as far from the sun will take say 2.5 times as long to orbit.

Earth is 1AU distance and 1 year orbit.

Mars is 1.66AU distance and 1.88 years orbit

Jupiter is 5.46AU distance and 11.86 yearsorbit.

Answer 6

There are 3 laws :

1) The orbit of every planet is an ellipse with the Sun at one of the two foci.

2) The line joining the planet and the Sun sweeps out equal areas of the ellipse

in equal times.

3) The orbital period squared is directly proportional to the cube of the ellipse's

semi-major axis.

Obviously you may need more help with this if you're not familiar with some of the

words used.

Answer 7

-- The orbits of the planets are ellipses, with the sun at one focus.

(Same for comets, asteroids, moons, artificial satellites, and any spacecraft

that hasn't left the solar system and isn't firing rocket thrust at the moment.)

-- A line from the sun to the planet sweeps out equal areas in equal times.

(The satellite travels fastest when closest to the central body, and slowest

when farthest from it.)

-- The squares of the orbital periods of the planets are proportional to the

cubes of the semi major axes of their orbits.

(The orbital period only depends on distance from the central body, and not on

the satellite's mass.)

Answer 8

-- The orbits of the planets are ellipses, with the sun at one focus. (Same for comets, asteroids,

moons, artificial satellites, and any spacecraft that hasn't left the solar system and isn't firing

rocket thrust at the moment.)

-- A line from the sun to the planet sweeps out equal areas in equal times. (The satellite travels

fastest when closest to the central body, and slowest when farthest from it.)

-- The squares of the orbital periods of the planets are proportional to the cubes of the

major axes of their orbits.

(The orbital period only depends on distance from the central body, and not on the satellite's mass.)

Answer 9

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