At the equator how fast does earth rotate

In , the COBE satellite was placed in orbit about the earth again, the earth is the frame of reference! This radiation, which remains from the immensely hot and dense primordial fireball that was our early universe, is known as the cosmic microwave background radiation CBR. The CBR presently pervades all of space. It is the equivalent of the entire universe "glowing with heat. Because the CBR permeates all space, we can finally answer the original question fully, using the CBR as the frame of reference.

The earth is moving with respect to the CBR at a speed of kilometers per second. We can also specify the direction relative to the CBR.

It is more fun, though, to look up into the night sky and find the constellation known as Leo the Lion. The earth is moving toward Leo at the dizzying speed of kilometers per second. It is fortunate that we won't hit anything out there during any of our lifetimes! Already a subscriber? Sign in. So how fast exactly is Earth moving around the sun? Some of the earliest astronomers in recorded history proposed that we live in a geocentric universe in which Earth lies at the center of everything.

According to them, the sun rotated around us, which caused sunrises and sunsets — same for the movements of the moon and the planets. But even then, there were certain things that didn't exactly line up with these theories. For example, sometimes, a planet would back up in the sky before resuming its forward motion.

We know now that this back-and-forth — which is called retrograde motion — happens when Earth is "catching up" with another planet in its orbit.

For example, Mars orbits farther from the sun than Earth. So, at one point in the planets' respective orbits, Earth catches up to the Red Planet and passes it by. As we pass Mars by, it moves backward in the sky then forward again after we have passed. Related: How Big is Earth? Another reason that humans started to realize that we might not be the center of the universe came from looking at parallax , or apparent change in the position of the stars with respect to each other.

For a simple example of parallax, hold up your index finger in front of your face at arm's length. Look at it with your left eye only, closing your right eye. Then close your right eye, and look at the finger with your left.

The finger's apparent position changes. That's because your left and right eyes are looking at the finger with slightly different angles. The same thing happens on Earth when we look at stars. It takes about days for us to orbit the sun. If we look at a star located relatively close to us in the summer and look at it again in the winter, its apparent position in the sky changes because we are at different points in our orbit.

We see the star from different vantage points. With a bit of simple calculation, using parallax we can also figure out the distance to that star. Earth's spin is constant, but the speed depends on what latitude you are located at. Here's an example. The circumference distance around the largest part of the Earth is roughly 24, miles 40, kilometers , according to NASA.

This area is also called the equator. If you estimate that a day is 24 hours long, you divide the circumference by the length of the day. Related: Check out some stunning images of Earth from space. You won't be moving quite as fast at other latitudes, however. If we move halfway up the globe to 45 degrees in latitude either north or south , you calculate the speed by using the cosine a trigonometric function of the latitude.

The time it takes Earth to rotate so the sun appears in the same position in the sky, known as a solar day, is 24 hours.

However, the time it takes Earth to complete one full rotation on its axis with respect to distant stars is actually 23 hours 56 minutes 4. At the equator, its circumference is roughly 40, kilometres, so dividing this by the length of day means that, at the equator, Earth spins at about kilometres per hour. As you move north or south, the circumference of Earth gets smaller, so the speed of spin reduces until it reaches its slowest at both poles.

And all of this is nothing compared with the , kilometres per hour at which Earth orbits the sun. Simply put, as Earth is spinning at a constant speed, so does everything on it.