Why do planets orbit the sun and not the other way around?

Answer 1

Actually, this is why planets orbit the sun, but not why they don't fall into it. It is the motion of the planets that keeps them from falling into the sun. Since the solar system formed from a spinning gas cloud that began to spin faster and faster as gravity squished it (gravity pulls toward the center...which is why planets and stars are round) all the planets spin around the sun (orbit) and rotate on their axis. Smaller planets close to the sun spin more slowly, because the sun's gravity has gradually slowed them down. This is also why the moon always has the same side facing the earth.

Another Viewpoint:

The planets have their own velocity. This combines with the Sun's gravity to produce a stable orbit around the Sun.

Answer 2

Whatever makes you think that the planets should be arranged in ascending or descending order of mass? Why not in alphabetical order, or some other order?! There are various theories about how the planets formed, and how they acquired their initial velocity and angular momentum. Whichever theory is correct (even the creationist view) one thing is for sure: the planets' orbits are remarkably stable. Only a very small proportion of their energy and angular momentum is exchanged with other bodies (Neptune and Pluto are a mild exception to this). So the planets simply stay in the relative orbits that they had when they initially settled into stable orbits, as the solar system was taking shape. There is no physical force which should cause the more massive planets to swap places with other planets in order to reach your proposed order by mass. The period of rotation of a planet (which is small compared to the sun) is not a function of its mass, only a function (Kepler's laws) of the distance from the sun.

Answer 3

From observations it's impossible to know whether the planets revolve round the Sun or the other way round. But after Newton produced laws of motion in the 18th century and then ideas of energy were formulated, it could be shown that if the very massive Sun was rotating around one of the planets, the amount of kinetic energy in that system would be 'astronomical'.

Nature tends to find ways of minimising the energy in a system, and the minimum energy is achieved with the Sun staying in one place and the planets rotating round it.

Of course the Sun does not actually stay in one place, it is rotating around the centre of the Galaxy, taking us with it.

Answer 4

That's because of the "inertia" of the planets.

That's the tendency to move in a straight line unless a force is acting on them.

If the Sun's gravity magically suddenly disappeared the planets would "fly off" into space.

So, the Sun's gravity is balanced by this tendency of the planets to move in straight lines.

The result is the curved path of a planet's orbit.

Answer 5

The Sun's gravity is pulling the planets in, so how do they keep out? the answer is in their forward speed which gives them enough momentum to stay in their orbits. The effect of gravity is to make each planet curve towards the Sun continuously in its elliptical orbit. Without gravity the planets would just travel in straight lines.

The orbits are extremely stable, with constant total energy, and barring catastrophic collisions with very large objects they are expected to remain as they are for millions of years.

The eight planets each have enough gravity to have swept up the debris in the vicinity of their orbits so the probability of such collisions is extremely low even over a million-year timescale.

Answer 6

Planets orbit the sun due to the gravitational pull of the sun. The sun is much more massive than the planets, so its gravitational force keeps the planets in orbit around it. This is in accordance with Newton's law of universal gravitation.

Answer 7

The sun has about 700 times the mass of all the planets combined.

Answer 8

suns are bigger