Johannes Kepler

We learned many things from the Scientific Revolution, including space science. Johannes Kepler was one of the few people that made immense discoveries about space. Kepler discovered laws of planetary motion and how planets rotated around the sun.

Kepler was a German astronomer, mathematician, and astrologer (1571 - 1630). Kepler was also Tycho Brahe’s assistant, and later he asked Kepler to study Mars. Kepler tried to make a negotiation to make a more formal employment, but it turned into an argument which made Kepler move to a city named Prague in April 6, 1600. In June, Brahe and Kepler reached an agreement to give Kepler a better salary.
Kepler also supported the theory of the earth rotates around the sun, or that our solar system was heliocentric. He didn’t agree with Tycho Brahe’s geocentric theories even though he was a student of Brahe. He agreed with Copernicus who came up with the idea of a heliocentric solar system, but modified his idea (orbital path). Later in history, this helped Isaac Newton’s theory of gravity. Gravity was the reason why planets stayed in orbit.

Later in his studies, he observed the planets and discovered these three laws of planetary motion:

His first law states that the orbit of each planet is an ellipse with the Sun at a focus.

His second law is states a line between a planet and the Sun sweeps out equal areas in equal times. Planets travel faster when they are closer to the sun (perihelion), and slower when they are further from the sun (aphelion).

Kepler’s third and last law states that the square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit. That means if you know the year of the revolving object, you square the year (yr2) and you cube root yr2 .That will get you the distance to the sun in AU (Astronomical Units). This doesn’t only work for planets; it also works for moons, dwarf planets, satellites, etc. This equation can also be expressed as P2=A3. P represents the orbital period, and A represents the semi-major axis of the orbit (distance to the sun).

In brief, Kepler gave an enormous contribution to the Scientific Revolution. He discovered laws about our solar system, and even helped Isaac Newton create the theory of gravity. Without Kepler, we would know very little about our solar system. We might also think that Nicolaus Copernicus was right and the orbit around the sun was a perfect circle. Kepler cleared things up for us and helped modern science. The Scientific Revolution has influenced modern space science in a wonderful way. All of the scientist worked on theories for a long time and it was then completed. Copernicus gave the correct heliocentric idea, Kepler modified his idea to make the orbits ellipses, and Newton found gravity to explain why the planets are in orbit. These intelligent scientists discovered how our solar system works and now we can look back at their theories for modern science.