hello!!!!please help me with my assignment..who is johannes keepler?

Question

help me please!!!

Answer 1

Johannes Kepler (1571-1630) was a German astronomer who worked as assistant to the Danish astronomer Tycho Brahe in Prague, and when Brahe died unexpectedly in 1601, Kepler took over Brahe's work.

He is best known for his 3 Laws of Planetary Motion which resolved centuries of wrangling about epicycles as a way of explaining the retrograde motion of planets.

They also helped establish the Copernican theory of a heliocentric Solar System, published in 1543, as did Galileo's observations in 1610, using a telescope and discovering that Jupiter had 4 moons that went around it, and not around the earth as the geocentrism theory claimed.

When Sir Isaac Newton published Principia Mathematica in 1687, developing his three laws of motion and his universal theory of gravitation, it became clear that Kepler's Laws could be derived from Newton's, though Kepler did not know of them when he developed his Laws in 1605 and the two men never met.

Kepler's Laws state that:

(1) all planets move in ellipses with the sun at one of the two foci of the ellipse.

(2) planets sweep out equal areas in equal time i.e. go slower when further away from the sun and go faster when nearer to it

(3) the squares of the orbital periods of planets are directly proportional to the cubes of their semi-major axes (the "length" of the ellipse) of their orbits.

The second link explains the laws in more detail, the first one is more biographical, about Kepler himself.

Answer 2

Do you mean Johannes Kepler? He was a German Lutheran mathematician, astronomer and astrologer, and a key figure in the 17th century astronomical revolution. He is best known for his eponymous laws of planetary motion, codified by later astronomers based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican Astronomy.
Before Kepler, planets' paths were computed by combinations of the circular motions of the celestial orbs. After Kepler, astronomers shifted their attention from orbs to orbits—paths that could be represented mathematically as an ellipse

Answer 3

Kepler was the guy who finally took the huge archive of celestial observations accumulated by Tycho Brahe and his predecessors and organized them and analyzed them.

Just by looking at the patterns in celestial observations, he figured out that planets orbit the Sun in ellipses instead of circles or epicycles (the most popular theories of Kepler's time).

He also figured out that the area swept out per second stayed constant (areal velocity stays constant). While planet moved faster when it was closer to the Sun, meaning it swept out bigger angles per second (angular velocity), it was balanced out by the shorter radius near the Sun, keeping the areal velocity constant.

It took him about 10 more years to come up with his third law that described the relationship between the time it takes to complete an orbit and the average radius. The square of the orbital period (time it takes to complete an orbit) is proportional to the cube of the average distance.

It's kind of surprising that it would take 10 more years, since the third law is a direct result of the second, but it kind of emphasizes how he was coming up with these patterns. He was relying strictly on patterns in observations instead of trying to determine why the patterns would exist.

Answer 4

Johannes Keepler?? No, I think you mean Kepler. Now you can Google his name and get all that handy-dandy info for your homework assignment, instead of tying me up, looking it up for you.

Answer 5

If you mean Kepler, not Keepler... then:

http://en.wikipedia.org/wiki/Johannes_Kepler

http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Kepler.html

http://galileo.rice.edu/sci/kepler.html

http://kepler.nasa.gov/johannes/

Answer 6

a greatest anstronomer of his time . you can know more about him by typing him name in google.com but make sure its johannes kepler.

hope this helps

Answer 7

http://kepler.nasa.gov/johannes/

Here you go ..a site that tells you all.

Answer 8

try looking up kepler