Earth's Rotation: Day & Year Cycles

[Raza]

Which way does the Earth rotate and why? I am talking about both of the rotations. Rotation for a day and a rotation for an year.

 

[scott1]

It rotates to the east.

I don't know why.

 

[SpaceTiger]

...and why?

Probably because molecular cloud that was to form our solar system was slightly torqued by a passing massive object or spiral arm, but it's hard to say.

 

[yenchin]

It rotates to the east.

I don't know why.

Or, it rotates anticlockwise if viewed above the north pole.

 

[DaveC426913]

BTW, when it's around the Sun, it's called 'revolution', not 'rotation'.

The Earth rotates counter-clockwise as viewed from above the pole (and above the Solar System). As do all other planets in the SS (Venus too, but it is a special case**).

The Earth revolves around the Sun counter-clockwise, as do all other planets in the SS.

The SS revolves around the galactic core counter-clockwise, as does almost everything else in the galaxy.

These rotations are interlinked, and it is pretty likely that they all stemmed from the same initial bias in rotation as - first the galaxy, then the solar system, then the gas cloud that formed the Earth - all had.

**Venus rotates counter-clockwise, just like all the other planets, however, since its rotation (about its own axis) is actually slower than its revolution (about the Sun), the net effect is that the Sun rises in Venus' West and sets in it East and thus Venus is said to have a retrograde rotation. (Interestingly, this means Venus' "day" is longer than its "year".)

 

[SpaceTiger]

I think both Uranus and Pluto rotate clockwise (axial tilts > 90 degrees). As for Venus, its solar day (i.e. the day as seen from someone on the surface) is ~117 days, suggesting that that it would also be rotating clockwise from a stationary vantage point north of the solar system.

 

[DaveC426913]

I am splitting the Venus question off to https://www.physicsforums.com/showthread.php?t=119953" to ask for clarification.