# Planets' and Sun's mean angular velocity

FutureScience
From "[URL [Broken] Wikipedia - Earth's rotation[/URL]

The angular speed of Earth's rotation in inertial space is (7.2921150 ± 0.0000001) ×10−5 radians per SI second (mean solar second). Multiplying by (180°/π radians)×(86,400 seconds/mean solar day) yields 360.9856°/mean solar day, indicating that Earth rotates more than 360° relative to the fixed stars in one solar day.

If I want to know the mean angular velocity for any other planet of the Solar system and for the Sun itself, should I take the rotation period for each object and do the inverse in order to get the angular velocity in rad/s?

Here there is a list of rotation periods for the above objects:

http://en.wikipedia.org/wiki/Rotation_period

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## Answers and Replies

Staff Emeritus
Gold Member
From "[URL [Broken] Wikipedia - Earth's rotation[/URL]

The angular speed of Earth's rotation in inertial space is (7.2921150 ± 0.0000001) ×10−5 radians per SI second (mean solar second). Multiplying by (180°/π radians)×(86,400 seconds/mean solar day) yields 360.9856°/mean solar day, indicating that Earth rotates more than 360° relative to the fixed stars in one solar day.

If I want to know the mean angular velocity for any other planet of the Solar system and for the Sun itself, should I take the rotation period for each object and do the inverse in order to get the angular velocity in rad/s?

Taking the inverse of the rotation period will give you rotations per sec. Since a full rotation consists of 2 pi radians, you will have to multiple this by 2 pi to get rad/s.

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FutureScience
The data that I've about the mean angular velocity, all in rad/s are:

Earth = 7.292115053925690e-05,

Jupiter = 1.773408215404907e-04,

Mars = 7.088218127178316e-05,

Mercury = 1.240013441242619e-06,

Moon = 2.661699538941653e-06,

Neptune = 1.083382527619075e-04,

Pluto = -1.295641039282477e-05

Saturn = 1.636246173744684e-04,

Sun = 2.865329607243705e-06,

Uranus = -1.041365902144588e-04

For the Sun and for the bigger planets I've taken the equatiorial/deep interior value for the roation period.

Could anyone please crosscheck them or verify those number in some book or papers?