How fast are we spinning

[amarillis]

How fast does the earth revolve (in mph) so that it makes one revolution of its axis in 24 hours, and what speed is it going so that it circles the sun once a year?

[peppyuk]

I think the surface of the earth moves at around 1000mph as the earth spins, but you would have to take into account the speed of the earth moving, not just around the sun, but in total, I mean how do we know we're not moving at 10,000,000mph? If everything else is moving at the same speed you wouldn't even know your moving.

[peppyuk]

just worked it out that the earth will move at around 66,625.6mph around the sun, that speed would be relative to the sun.

[stoo_pid]

The answer to the first part of your question can't really be answered in mph - a point on the equator, for example, would be moving faster than a point at one of the poles because it has to cover a further distance in one revolution, yet they've both revolved 1 turn.

To give you an idea though, the diameter of the earth is approx 7,900 miles at the equator, which means a point on the equator would be moving at approximately 329mph to make 1 revolution in a 24 hour period.

 

[secretsquiz]

according to bill bryson's short history of nearly everything, at the equator, the earth moves at about 1000mph, but as peppyuk says the further from the equator you are, the slower it moves.

for example the speed of the earth if you are in the uk is around 990mph (if i remember correctly) and it obviously gets slower as you go further north.

[Moog]

Your calculation is wrong stoo_pid the circumference of the earth at the equator is 24,902 miles so for one revolution in 24hours the earth travels at 1038 miles per hour at the equator, however at the poles there's not rotation at all.

The earth's orbit around the sun is elliptical but on average the earth is 93 million miles from the sun which means it travels approximately 585 million miles in a year which is 1.6 million miles a day or 66,000 miles an hour

[bernardo]

...or 19 miles per second

(as quoted in the Monty Python "Galaxy Song")

[stoo_pid]

Doh!  thanks Moog.  I must admit, 300mph didn't seem very quick to me!  God only knows where I got 7,900 miles from...

[stoo_pid]

Ah, just sussed out what I did.  Bit more homework for me I think!

[Moog]

Your figure was right stoo_pid the diameter of the earth is about 7900 miles but its the circumference that is relevant for working out the speed

[helghast]

what about the fact that a point on the equator is moving about the earths centre yet it is also moving around the sun at the same time.

wouldn't it be going further than 24,902 miles

[sft42]

The best way to remember these figures is to know the Galaxy Song by the Monty Python guys....It goes like this:

 

Whenever life get you down, Mrs. Brown,
And things seem hard or tough.
And people are stupid, obnoxious or daft,
And you feel that you've had quite enu-hu-hu-huuuuff!
Just - re-member that you're standing on a planet that's evolving
and revolving at 900 miles an hour,
It's orbiting at 19 miles a second, so it's reckoned,
the sun that is the source of all our power.
The Sun and you and me, and all the stars that we can see,
are moving at a million miles a day,
In the outer spiral arm, at 40,000 miles an hour,
of the Galaxy we call the Milky Way.
Our Galaxy itself contains 100 billion stars,
it's 100,000 light-years side-to-side,
It bulges in the middle, 16,000 light-years thick,
but out by us it's just 3000 light-years wide.
We're 30,000 light-years from galactic central point,
we go round every 200 million years,
And our galaxy is only one of millions of billions
in this amazing and expanding universe.
The universe itself keeps on expanding and expanding,
in all of the directions it can whizz,
As fast as it can go, at the speed of light you know,
twelve million miles a minute, and that's the fastest speed there is.
So remember, when you're feeling very small and insecure,
how amazingly unlikely is your birth,
And pray that there's intelligent life somewhere up in space,
because there's ****** all down here on Earth.
 

[Moog]

Remember... or cut and paste? ;o)

[bernardo]

That's what I said 5 answers earlier.