The Earth takes one year (just a bit over 365 days) to revolve around the sun. The planet travels about 942 million kilometers (585 million miles) during its revolution, and the shape of its orbit is elliptical. Different planets have different revolution times: The closer a planet is to the sun, the shorter its revolution. At its furthest distance, the Earth is about 150 million kilometers (94 million miles) away from the sun.
Gravity is the force that causes an object with more mass to pull in an object with lesser mass; according to Albert Einstein's general theory of relativity, this is caused by the more massive object creating a curve in space-time. The effect of gravity can be calculated using Newton's universal law of gravitation, the equation for which is F = G(M1 x M2/R^2), where "G" is the gravitational constant, the "M's" are the masses of the two objects and "R" is the radius of the distance between them. Because the sun has such a large amount of mass relative to its distance from the Earth, there is a strong force of gravity.
In addition to revolving around the sun, the Earth also rotates on its axis. The Earth's rotation takes one day, and it spins at a speed of about 1,670 kilometers per hour (1,000 miles per hour). In addition to rotating on its axis, the Earth also has a slight tilt in its rotation, which changes over the course of thousands of years; currently, the Earth's rotation is tilted toward the North Star.
Newton explained the cause of the Earth's rotation. His first law of motion states that once an object starts a certain motion, it will remain in that motion unless a force acts upon it. At some point during the formation of the solar system, a force caused the Earth to start spinning on its axis (possibly a collision with another celestial body), and because space is a vacuum, there was no subsequent force to stop this motion.