Why does the earth spin?

exhashdotdot · 12 Jan 2011 at 23:46

Ricochet J said:
It truly amazes me how a concept such as angular momentum which is applied to every day engineering applications is also applied on a larger astronomical scale.

Really? The concept of angular momentum (and rotational forces in general) is a pretty unanimous realm regardless of scale.

Subliminal Aura · 12 Jan 2011 at 23:52

Dad .... ' What TF is angular momentum ? '

.... a couple of years down the line

Dad .... ' Why does the water going down a drain in Australia spin in the opposite direction to here ? '

* be prepared *

stopper · 13 Jan 2011 at 00:13

davedudes said:
Four numbers, 2012, im worried are you?

Nope.
Were you worried in 1998,1999,2000 and 2004 also?

alexkyriak · 13 Jan 2011 at 00:25

Amp34 said:
True fact 3 - The earth isn't actually round...

its an Oblate Spheroid. Its wider at the middle. Like my missus.

(Never thought I'd get to say 'oblate spheroid' in a forum for the purposes of legitimate discourse.....!)

Inquisitor · 13 Jan 2011 at 00:40

Ricochet J said:
It truly amazes me how a concept such as angular momentum which is applied to every day engineering applications is also applied on a larger astronomical scale.

Really? It's just the rotational analogue of Newton's laws of (linear) motion. The only time you have to make adjustments is on the very small (quantum) scale and in the context of very strong mavity (general relativity) and very high velocity (special relativity).

Pate · 13 Jan 2011 at 00:44

How have people measured the Earth dimensions etc? Just out of curiosity.

Morba · 13 Jan 2011 at 00:54

alexkyriak said:
its an Oblate Spheroid. Its wider at the middle. Like my missus.

(Never thought I'd get to say 'oblate spheroid' in a forum for the purposes of legitimate discourse.....!)

You're welcome

Klo · 13 Jan 2011 at 01:08

kenmare said:
How have people measured the Earth dimensions etc? Just out of curiosity.

Tape measure.

deko · 13 Jan 2011 at 01:22

Subliminal Aura said:
Dad .... ' What TF is angular momentum ? '

.... a couple of years down the line

Dad .... ' Why does the water going down a drain in Australia spin in the opposite direction to here ? '

* be prepared *

Simple answer to that question, it doesn't.

PGdude · 13 Jan 2011 at 01:24

Just came into this thread to say that 2012 is one number and four digits.

asim18 · 13 Jan 2011 at 01:36

Money.

Mark A · 13 Jan 2011 at 01:37

kenmare said:
How have people measured the Earth dimensions etc? Just out of curiosity.

Trundle wheel.

Morba · 13 Jan 2011 at 01:38

asim18 said:
Money.

Lies. It's because people can get mac10 in 3 mins, so people be running everywhere, which through friction of people running in the same direction (as highlighted above) it turns the earth.

James07 · 13 Jan 2011 at 01:47

daz said:
Angular momentum

Surely one side of the planet will be heavier?

Given that though, why would it spin weather its on a 45 degree angle or 90 degree angle?

mavity from space?

silversurfer · 13 Jan 2011 at 02:08

Earth spins due to people running on top of it. Newtons 3rd law of motion says for every action there will be an equal and oppisite reaction hence we see 4 bn people mostly walk and/or drive west where all the money is and cause the earth to go in the oppisite direction thus provoking the earths continual spin
I'd like to thank my physics teachers for imparting all their knowledge

Ken · 13 Jan 2011 at 02:32

Don't quote me on this but I read from a reliable sauce (and I do believe this is the most plausible raisin) that the big man himself is essentially "plate spinning". The planets in our solar system sit on invisible tables and he keeps them spinning for both entertainment and also to allow everyone on earth their fair share of Sunny Delight.