The first indication that the sun rotates?

Answer 1

The rotation of the Sun can be detected by observing the motion of sunspots.

See related link for an animation.

Since the Sun is a ball of gas, it does not rotate rigidly like the solid planets.

In fact, the Sun's equatorial regions rotate faster (taking only about 24 days) than the polar regions (which rotate once in more than 30 days).

Answer 2

The first indication that the sun rotates came from observations of sunspots in the early 17th century. Galileo Galilei observed that sunspots appeared to move across the sun's surface, providing evidence that the sun rotates on its axis.

Answer 3

By observing sunspots we can figure out the suns rotational period. The Doppler effect can also be used to detect the speed of rotation. It should be noted that the sun is a large ball of plasma, and plasma has a fluid nature. As a consequence, the sun has what is called differential rotation. The plasma around its equator is rotating more quickly than the plasma nearer the poles.

Answer 4

This can be seen quite clearly from the movement of the sunspots.

This can be seen quite clearly from the movement of the sunspots.

This can be seen quite clearly from the movement of the sunspots.

This can be seen quite clearly from the movement of the sunspots.

Answer 5

We know it rotates about its axis because we experience day and night - phases through which we face the sun, then turn/rotate away from it.

We know it rotates around the Sun because if it didn't, we'd fall directly towards it.

We know the Earth rotates around the Sun and not the other way around because of inertia and angular momentum. Since the Sun is much larger than us, and therefore has hugely more inertia than us, we know that it must be sitting relatively still, for if it were to rotate around us, our gravitational pull would be insufficient to hold it in orbit. We must therefore be rotating around the Sun as it pulls us in to maintain our orbit around it.

It is just as legitimate to state that the Sun rotates around the Earth at a speed of one revolution per 24 hours, which uses the Earth as a point of reference, assuming it is fixed and stationary in space with the rest of the universe moving around it.

Answer 6

The rotation can be seen and measured by comparing the movement of visible points on the sun's surface with the movement of the Earth. Once the Earth's orbit and rotation are accounted for, the remaining observed movement is due to the sun's rotation.

There are mathematical proofs as well, having to do with the shape of the sun, conservation of angular momentum, etc., but the rotational observations are proof by themselves.

Answer 7

Because of the sunspots that appear on the sun surface . The sunspots move across the sun surface which makes a movement , this movement indicates that the gases in the sun rotates on its axis

Answer 8

We know the Sun rotates because we can watch sunspots on the face of the Sun.

Answer 9

One side is blue-shifted and the other side is red-shifted.

Answer 10

One side it's blue shifted and the other side it's red shifted