gRAVITY AND ECCENTRICITY
The elliptical orbit of a planet doesn't stay at a constant distance from the sun. Perihelion describes when a planet is closest to the sun in its orbit. Aphelion describes when a planet is its farthest distance from the sun in its orbit.
Eccentricity: This is the ratio of distance between the foci to the length of the major axis. Eccentricity ranges in value from 0 to 1. When a planet has an eccentricity of 0 its orbit is a perfect circle. On the other hand, when a planet has an eccentricity of 1 its orbit is a very elongated oval. The majority of the planets in our solar system have orbits that are not very eccentric.
Newton developed an understanding of gravity by observing the movement of our moon, the orbits of our planets, and the acceleration of objects falling into Earths atmosphere. With Newtons observations he discovered that two bodies attract each other with a force that depends on their masses, and the distance between the two bodies. The force between the two objects increases when the two objects are closer together, but as they distance each other the force weakens.
Gravity: The statement that Newton gave was known as the law of universal gravitation, which stated the relationship among the masses of two bodies and the force and distance between them. You can say that: Every pair of bodies in the universe attract each other with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them.
Center of Mass: Another thing that Newton determined was, each planet orbits a point between it and the Sun that's called the center of mass. This is the balance point between two orbiting planets. If one of the two planets orbiting each other is bigger than the other, the center of mass is closer to the bigger planet. If the planets have similar masses, this means the center of mass is near the middle of the planets. With each planet in our solar system, and the sun, the center of mass is above, or within the sun, because the sun has a bigger mass than any of the planets.
Eccentricity: This is the ratio of distance between the foci to the length of the major axis. Eccentricity ranges in value from 0 to 1. When a planet has an eccentricity of 0 its orbit is a perfect circle. On the other hand, when a planet has an eccentricity of 1 its orbit is a very elongated oval. The majority of the planets in our solar system have orbits that are not very eccentric.
Newton developed an understanding of gravity by observing the movement of our moon, the orbits of our planets, and the acceleration of objects falling into Earths atmosphere. With Newtons observations he discovered that two bodies attract each other with a force that depends on their masses, and the distance between the two bodies. The force between the two objects increases when the two objects are closer together, but as they distance each other the force weakens.
Gravity: The statement that Newton gave was known as the law of universal gravitation, which stated the relationship among the masses of two bodies and the force and distance between them. You can say that: Every pair of bodies in the universe attract each other with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them.
Center of Mass: Another thing that Newton determined was, each planet orbits a point between it and the Sun that's called the center of mass. This is the balance point between two orbiting planets. If one of the two planets orbiting each other is bigger than the other, the center of mass is closer to the bigger planet. If the planets have similar masses, this means the center of mass is near the middle of the planets. With each planet in our solar system, and the sun, the center of mass is above, or within the sun, because the sun has a bigger mass than any of the planets.