I assume that you are referring to the velocity of earth around the sun. If so here is the answer.

For our earth, the reference point would be the Sun and for the Sun and our galaxy, the reference would be the cosmic microwave background radiation (CMBR)and the neighboring galaxies.

"These measurements of galactic distance and speed are as accurate as can be, given current knowledge, but this may change as more is learned.15 Since our galaxy is moving with respect to the cosmic microwave background radiation (CMB) in the direction of Hydra with a speed of 550 km/s, the sun's resultant velocity with respect to the CMB is about 370 km/s in the direction of Crater or Leo."

Speed of Earth with respect to the Sun:

"First of all we know that in general, the time it takes to travel a distance is equal to the length of that distance, divided by the speed at which you travel that distance. If we reverse that, we get that the speed is equal to the distance traveled over the time taken.

We also know that the time it takes for the Earth to go once around the Sun is 1 year. So in order to know the speed we just have to figure out the distance traveled by the Earth when it goes once around the Sun. To do that we will assume that the orbit of the Earth is circular (which is not exactly right, it is more like an ellipse, but for our purpose it will do just fine). So the distance traveled in one year is just the circumference of the circle. (remember that the circumference of a circle is equal to 2*pi*Radius)

The average distance from the Earth to the Sun is 149,597,890 km. Therefore in one year the Earth travels a distance of 2*Pi*(149,597,890)km. This means that the velocity is about:

velocity=2*Pi*(149,597,890)km/1 year

and if we convert that to more meaningful units (knowing there is 365 days in a year, and 24 hours per day) we get:

velocity=107,300 km/h (or if you prefer 67,062 miles per hour)

So the Earth moves at about 100,000 km/h around the Sun (which is 1000 times faster than the speeds we go at on a highway!)"

Of course the Solar system is moving with respect to the galactic center and the Milky way galaxy is also moving with respect to other galaxies in the observable universe.

"The Sun orbits the center of the Milky Way galaxy at a distance of approximately 24,000–26,000 light years from the galactic center, moving generally in the direction of Cygnus and completing one revolution in about 225–250 million years (one Galactic year). Its orbital speed was thought to be 220±20 km/s, but a new estimate gives 251 km/s.14 This is equivalent to about one light-year every 1,190 years, and about one astronomical unit (AU) every 7 days. These measurements of galactic distance and speed are as accurate as can be, given current knowledge, but this may change as more is learned.15 Since our galaxy is moving with respect to the cosmic microwave background radiation (CMB) in the direction of Hydra with a speed of 550 km/s, the sun's resultant velocity with respect to the CMB is about 370 km/s in the direction of Crater or Leo.16"

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

Speed of our Galaxy with respect to other neighboring galaxies:

"Astronomers believe the Milky Way is moving at approximately 630 km per second relative to the local co-moving frame of reference that moves with the Hubble flow.44 If the Galaxy is moving at 600 km/s, Earth travels 51.84 million km per day, or more than 18.9 billion km per year, about 4.5 times its closest distance from Pluto. "

Speed of our galaxy with respect to CMBR:

"Another reference frame is provided by the cosmic microwave background (CMB). The Milky Way is moving at around 552 km/s3 with respect to the photons of the CMB, toward 10.5 right ascension, -24° declination (J2000 epoch, near the center of Hydra). This motion is observed by satellites such as the Cosmic Background Explorer (COBE) and the Wilkinson Microwave Anisotropy Probe (WMAP) as a dipole contribution to the CMB, as photons in equilibrium in the CMB frame get blue-shifted in the direction of the motion and red-shifted in the opposite direction."
Source(s):
http://curious.astro.cornell.edu/question.php?number=356

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

Asker's Rating:

Permalink | Report