Yeah, the subject pretty much covers it. Just curious.
jks
Well, the circumference of the earth at the equator is roughly 25000 miles, and a full rotation of the earth takes roughly a day, so figure something like 1000 miles/hour at the equator, and progressively slower speeds the further north/south you go.
Just, re-member that you’re standing on a planet that’s evolving and revolving at 900 miles an hour.
-Monty Pthyon
“The Galaxy Song”
I think that about covers it. I’m sure some Dopers will be along to give you an exact answer and convert it to metric for you if they haven’t already.
It depends on where you are standing. At the equator the earth rotates at around 1,040 mph.
The farther away from the equator you go the slower you will be moving. Multiply your equator answer by the cosine of your latitude to see how fast you are moving where you are. If you are standing at the poles you aren’t moving very fast at all as regards earth’s rotattion.
I’d say about 1 rpd. Roughly.
The earth rotates 365 1/4 times per year – give or take one.
Take one.
The year is 365 1/4 days long, but the earth rotates slightly more than once per day, in fact it rotates 1/(365.25) part of a rotation more than once per day.
If you add it all up, the earth has to rotate one additional time to make it work out, or 366.25 times per year.
The sidereal day (time it takes earth to rotate with respect to the “fixed” stars) is 23 hours, 56 minutes, 4 seconds. linky-link
The velocity of a point on the earth’s surface with respect to the center of the earth (assuming a spherical earth) is given by
2pR[sub]e[/sub]cos(L)
v = ----------
D[sub]s[/sub]
R[sub]e[/sub] = Radius of Earth
L = Latitude
D[sub]s[/sub] = length of sidereal day
Given a radius of earth of 6378 m, and 23.9345 hours as D[sub]s[/sub], this gives a velocity of 1675 km/h, or just over 1000 mph at the equator. At the poles, of course, the velocity is zero.
>> this gives a velocity of 1675 km/h
Which is close to nothing compared to the speed with which the planet Earth advances in its solar orbit which is something like 107227 km/h. Add them both and at midnight, at the equator, you are advancing at 108900 km/h. Subtract and at noon you are advancing at 105552km/h. So, we are all moving pretty much in the same direction and at the same speed, equator or other latitudes.
All speeds have to referenced to SOMETHING. A car going 60 mph is only going 60 mph with reference to the tree along the side of the road. Why necessarily pick the sun as the reference point? I think we should pick the center of the Milky Way and just call it done. That should be plenty fast enough.
You hurt my brain. Stop.
The earth rotates at 15[sup]o[/sup]/hour measured by the sun’s position. This rate is uniform (within limits - mean solar day and all that, you know) worldwide at all lattitudes.
As far as answers go, I like Great Dave’s Answer the best, its obnoxious, funny, mean and true!
Why do you want to know? Are you planning on jumping really high, waiting for the earth to rotate and then coming down really far away? Cause if that was your plan, it won’t work.
Or are you planning on sending a pulsed neutrino beam back where the earth used to be as a form of time travel communication?
What’s the straight dope?
-Sandwriter
True, but how fast is the Milky Way expanding from the center of the universe? Maybe that should be our fixed point, no?
But I’m at the centre of the Universe. Should all speeds be measured relative to me?
[sub]course, everybody else is too, but I claimed it first…[/sub]
Not to pick on pulykamell, but as often as people make this statement around here, it amazes me that it’s not taught to everyone in grade school, right after the fact that the earth is round and the Louisianna purchase was in 1803, that there is no center of the universe.
-b
It doesn’t rotate. It’s flat. Everything else moves around it.
At least, that’s what the nutter sitting next to me thinks.
(Fortunately, only temporarily or I’d have to plead justifiable homicide. But that’s another story.)
Oooo…man, I did think that something sounded wrong when I wrote “center of the universe,” but then I thought, well, if the Big Bang began from a fixed point, can’t that spot be construed as the center of the universe? Or, more likely, am I thinking about this totally the wrong way.
Well, it’s more like everything came from the point at the big bang.
Think of an inflating sphere, where the surface of it represents the universe. It starts from a tiny point and then swells up, and anything you’ve drawn on the surface (like galaxies and all) move away from each other as it gets bigger.
Now, it doesn’t really make sense to say “this is the top of the sphere” and this is what bryanmcc meant when he says the there’s no centre to the universe.
Alternatively, you might just as well designate any point you liked as the “top” and this is what I meant when I said I was at the centre of the universe.
SIGH… yes, pulykamell, you are thinking about it the wrong way. There is no “center” from which the universe is expanding. Do a search for “center” and “universe” and I’m sure you will find one of fifty threads where we try to smash it into people’s brains that there really is no such thing, as centers go.
Technically, we’re at the center of the observable universe. That’s not because we’re at some preferred location, just because light has a constant speed in all directions and we just can’t see beyond the speed of light times the age of the universe.
If you want a truly interesting frame of reference against which to measure our velocity, you can use the Cosmic Microwave Background Radiation. The biggest contribution to our velocity with respect to that actually comes from the whipping around the center of our Milky Way.
Sorry, JS…never read those threads. Didn’t much think about the concept of the universe having a center before, since I assumed the universe to be infinite. But it’s finite, right? Wrong? Ahh…sod it… In 100 years, the opposite we’ll find data supporting the opposite theory. 
But I did google, and find out that the concept of a center, as such, does not exist. The inflating sphere example seems to be the most comprensible one I’ve read.