I found this interesting:

http://64.45.37.69/Science/Astronomy/earth.html

According to the author we do know:

The Earth revolves around the Sun once a year. The orbit of the Earth is not quite a perfect circle but pretty close. The perihelion (point closet to the Sun) is 147.1 million km, which is about 91,407,940 miles (take .6214 x 147.1 million). The aphelion (farthest point from the Sun) is 152.1 million km, which is about 94,514,940 miles.

The average distance would be 149,600,000 km or 92,961,440 miles. This number is rounded off to 93,000,000 miles.

Another measurement in astronomy that you may encounter is AU (astronomical unit). 1 AU is equal to the average distance of the Earth from the Sun, or 93,000,000 miles.

I hate to be a pest, but let's take a quick look at some math that we have just seen. 147.1 million km is 147,100,000 km. We want to multiply that number by .6214 miles, since that is how many miles there are in 1 km.

When you start to get into some large numbers you will run out of calculator space. Therefore, you would need to use scientific notation. In our case, we have 1.471 x 108 times 6.214 x 10-1. Now it is a simple matter of multiplying 1.471 x 6.214 (any calculator should be able to handle this), which gives us 9.140794. Now add the exponents and you come up with the number 7 (8 + (-1)). This gives us 91,407,940 miles.

The speed of the Earth around the Sun varies. The closer the Earth is to the Sun the faster the Earth is traveling in its orbit, and the farther it is from the Sun the slower the Earth is traveling. In all cases though, the Earth is traveling around the Sun in excess of 60,000 mph, and will make a complete orbit in one year.

The speed at which the Earth travels around the Sun in its orbit, is not to be confused with the speed at which the Earth is rotating while it orbits the Sun. Depending on where you are, the speed of that rotation will vary from 0 km/hr at the North Pole to 1,650 km/hr (approx. 1025 mph) at the equator.

As the Earth rotates it is also tilted at a 23 1/2 0 angle to the perpendicular. The axis of the Earth is always pointed directly at the North Star, Polaris. The star Polaris is about 10 off of true north.



>>Hi Hilmar,
>>
>>Do we yet know where the earth is going, or from where it came. I suppose we know
>>at what speed it is traveling.
>
>No, we don't "know" at what speed Earth is travelling, or in what direction. That is to say, it just doesn't make sense to talk about an "absolute velocity". We can use a reference point, like the Sun, the center of the Milky Way, or the center of mass of the Local Cluster (group of galaxies), and calculate the velocity in relationship with that reference point.
>
>According to the generally accepted Relativity Principle, any one reference point is as good as any other one. The Relativity Principle is not the same as the Theory of Relativity, but it does play an important part in it.
>
>>Light only has one speed, which is very fast, approxiamtely 186000 miles per second
>>This could be used to determine at what speed earth is moving through space.
>
>The negative result of the Michelson-Morley experiment reveals that this is not so. Light always moves at 300,000 km./sec., independent of the observer. Now, this is contrary to "common sense": if I run at 10 km./sec. after a car that moves at 60 km./sec., I would expect it to have a relative velocity of 50 km./sec. (relative to me). Measurements have revealed that in the case of a light-ray, this is not so.
>
>The explanation, according to the Theory of Relativity, is based on the fact that neither measures of length nor of time remain constant at different speeds.
>
>> How do
>>we judge the distance of star far away from earth. Since straight lines and circles
>>may not be exact and a star 300 millian light year away from earth would make
>>trianglation unusable, since we could not form a base of a triangle with enough
>>distrance between two point to provide the angles needed.
>
>Triangulation (paralaxis (spelling?), based on the fact that the Earth's orbit around the sun has a diameter of 300 million km.) is used for stars that are relatively close-by. The discrepancy I mentioned for light rays not being straight is negligible in this case.
>
>For larger distances, measurements are based on other methods, including estimations based on absolute brilliance: for instance, a supernova of a certain type is supposed to have a certain brilliance, at least on the average; at greater distances, it will look weaker. Another method, especially for far-away galaxies, is based on the fact that the Universe expands. The farther away an object, the faster it will recede. This can be calculate with great accuracy due to the Doppler Effect. The problem, of course, is to fix the absolute scale with other methods (the relationship between speed of recession and distance, that is, if a galaxy recedes at half the speed of light, what is its distance).
>
>>at some high rate of speed, not sure of either our point of origin or our point
>>of destination, yet if someone asked if I had moved within the last fifteen minute,
>>I would answer no.
>
>And this is correct, if you take the Earth as reference point. Remember, any one reference point is as good as any other one.
>
>Regards, Hilmar.