Also, the ratios of distance to the Sun and the Moon are not actual observations in the heliocentric theory. That’s the reason for Aristarchus’s model non acceptance.

Galileo first discovered that the Moon had mountains just like Earth. He also discovered 4 of Jupiter’s moons. Using his telescope, Galileo made many observations of our Solar System. He came to believe that the idea that the Sun and other planets orbited around the Earth was not correct.

He solved Ptolemy’s model by proving elliptical orbits. He determined that planets move faster when closer to the Sun. He discovered laws of planetary motion.

Though Kepler is best known for defining laws regarding planetary motion, he made several other notable contributions to science. He was the first to determine that refraction drives vision in the eye, and that using two eyes enables depth perception.

What was Tycho Brahe’s greatest contribution to astronomy? He first used the telescope to make extensive astronomical observations. He determined that the planets orbit the Sun in elliptical orbits. He proposed some simple laws that govern the motion of the planets and other objects.

There are actually three, Kepler’s laws that is, of planetary motion: 1) every planet’s orbit is an ellipse with the Sun at a focus; 2) a line joining the Sun and a planet sweeps out equal areas in equal times; and 3) the square of a planet’s orbital period is proportional to the cube of the semi-major axis of its …

These laws can be applied to model natural objects like planets, stars, or comets, as well as man-made devices like rockets and satellites in orbit. Although Kepler originally developed his laws in the context of planetary orbits, the results hold for any system with a radial force obeying the inverse square law.

The orbits of the planets are ellipses with the Sun at one focus, though all except Mercury are very nearly circular. The orbits of the planets are all more or less in the same plane (called the ecliptic and defined by the plane of the Earth’s orbit).

“The moon keeps the same face pointing towards the Earth because its rate of spin is tidally locked so that it is synchronized with its rate of revolution (the time needed to complete one orbit). In other words, the moon rotates exactly once every time it circles the Earth.

If we assumed that earth orbit is circular than season will changed slightly by 10 percent. Heat on earth from sun due elliptical orbit or distance change is approximate 10 percent only. Rest of season change due earth tilt on its axis. So this will be the only impact due circular orbit.

A circle is a special case of an ellipse with the major and minor axes equal. To get a perfectly circular orbit of a certain radius requires the planet to have a certain velocity, which is extremely unlikely.

All planets in our solar system follow an elliptical path. This path is known as an orbit. Earth’s orbit is not a perfect circle.