It was left to later astronomers like Johann Kepler and Sir Isaac Newton to explain the more elliptical paths of orbiting planets. The earth, we now realize, is just one of perhaps countless planets circling around other stars in other corners of the universe. Wednesday In light of a recent discovery of another entire solar system several weeks ago, we're been talking about our own solar system and what makes it tick. Gravity is a force that happens between any two objects, and its intensity depends on the relative size of the objects and the distance between them. If the earth were twice as far from the sun as it is now, the sun's gravitational pull on us would only be a quarter of what it is now.
Planets also exert a gravitational pull on each other, but size matters.
The sun is by far the biggest thing in the solar system, and keeps everything circling around it. Since Pluto was discovered in 1930, no planet circling a sun-like star had ever been found. Then, beginning in October of 1995, astronomers began finding planets orbiting distant stars. A few weeks ago, two teams of researchers announced the discovery of an entire solar system, located a mere 44 million light years away. Researchers cannot actually see these new planets with telescopes.