They don't. They move in ellipses around the Sun.
Planets rotate around the sun. The path is not really circular for planets, it is actually ellipsoidal.
Elliptical orbits of the planets around the sun actually match what we observe. Newton's Theory of Universal Gravitation states that planets will move around the sun in elliptical orbits.
Isaac Newton
Einstein revised our idea of planetary orbits in his theory of relativity, which says that planets orbit the sun because of the sun's distortion of space. This distortion causes space to bend. The planets move along this bend. Think of a Bowling ball placed on a mattress. The ball causes a circular dent in the mattress. If you shoot a marble at the ball, the marble will move around the bowling ball in a circle along the path of the indentation. In the same way, the planets revolve along the indentation the sun makes in space.
Generally speaking, yes. It should be noted however that the outer planets have a more elliptic orbit (egg shaped).
They all do. Some planets are closer to a circular orbit than others (have a lower eccentricity), but none are exactly circular.
kepler
One could explain that in a "classical" way by saying that the electron moves around the nucleus much the same way that planets move around the sun. The planets want to naturally move along a straight line but is prevented from doing so by the pull of the sun. In the same way, electrons would, if left to itself, move along a straight line. However, the attraction from the positive nucleus makes them move in a circular path. In a sense the electron falls down toward the nucleus instead of moving along a straight line. Santosh
yes, they do.
Yes, because of the gravity of the sun they are moved in a circular motion that goes at a certain speed depending on the distance of the planets and centripetal forces. All the planets in out solar system revolve around the sun, while rotating on it's axes.
Yes. All planets move in orbit around their host star.
Planets have to go in different directions all the time because they all follow orbits that are more or less circular.