# What is the rotation of a star?

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## What is the rotation of a star?

Stars appear to be rising and setting, as well as the planets, Moon and the Sun. Stars that are close to the Earth’s axis of rotation—what we call the north and the south pole—rotate around the poles. If the pole’s location is far enough above the horizon, some stars never set. They just keep spinning.

What is a rapidly rotating star?

A rotating star may be modeled as a continuous system of particles attracted to each other by gravity and with a given total mass and prescribed angular velocity. We prove an existence theorem for such stars that are rapidly rotating, depending continuously on the speed of rotation.

Do stars spin?

Not only stars can spin. Dead stars can spin too, and they take this to a whole other level. Neutron stars are what you get when a star with much more mass than the sun detonates as a supernova.

### What causes a star to spin?

Stars are believed to form as the result of a collapse of a low-temperature cloud of gas and dust. As the cloud collapses, conservation of angular momentum causes any small net rotation of the cloud to increase, forcing the material into a rotating disk.

Is the Sun spinning?

Yes, the Sun absolutely spins. In fact, everything in the universe spins. And here’s another interesting Sun spin fact: the middle part of the Sun – its equator – spins more quickly than the top and bottom parts, which are called the Sun’s poles. It can do that because the Sun isn’t solid, it’s a ball of gas.

Is the universe rotating?

Almost everything in the universe spins. Planets rotate on their axis, stars spin around black holes, and galaxies spin in great spiral structures. Structures rotate because of a property known as angular momentum. Angular momentum is a measure of mass and rotation, and it is a conserved physical property.

## Do all black holes spin in the same direction?

Summary: Deep radio imaging has revealed that supermassive black holes in a region of the distant universe are all spinning out radio jets in the same direction — most likely a result of primordial mass fluctuations in the early universe.

How is the rate of rotation of a star measured?

The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface. The rotation of a star produces an equatorial bulge due to centrifugal force.

When does differential rotation occur in a star?

Differential rotation. Surface differential rotation is observed on stars such as the Sun when the angular velocity varies with latitude. Typically the angular velocity decreases with increasing latitude. However the reverse has also been observed, such as on the star designated HD 31993.

### Which is the fastest rotating star in the universe?

The equatorial radius of this star is 32% larger than polar radius. Other rapidly rotating stars include Alpha Arae, Pleione, Vega and Achernar . The break-up velocity of a star is an expression that is used to describe the case where the centrifugal force at the equator is equal to the gravitational force.

Why does the rotation of a star produce an equatorial bulge?

The rotation of a star produces an equatorial bulge due to centrifugal force. As stars are not solid bodies, they can also undergo differential rotation. Thus the equator of the star can rotate at a different angular velocity than the higher latitudes.