# Does General Relativity allow earth to be defined as a fixed reference frame?

## Post of the Month: February 2007

by

```Subject:    | Can Koppe produce conclusive evidence that the earth is NOT fixed? His bluff called
Date:       | 20 Feb 2007
```

Tony Pagano wrote:
>> Whether the earth is fixed or not is a matter of your frame of reference
>> according to relativity. If Relativity is to be believed it says there is
>> no privileged frame of reference. One could just as easily choose the
>> earth as a fixed frame of reference.

Jim Guillory wrote:
I've seen this creationist argument before, so I'ld like to toss in my two cents.

The theory of special relativity is restricted to unaccelerated reference frames, but in the general theory even frames that are accelerated relative to each other can be shown to be mathematically equivalent. This does not help the creationists as much as they think.

In the general theory, one can mathematically make any frame of reference stationary if one warps the geometry of space in the correct manner. Mathematically, my dog's butt could be the stationary center of the universe. But when one tries to apply this to a stationary earth, well, unfortunately for Pagano, the devil is in the details.

First, while a frame of reference may be accelerated, the different parts of that frame cannot be accelerated with respect to each other. Here is the first problem for the stationary Earth model. Several experiments (Foucault, coriolis effect, measurements of variations in gravity) show that different parts of the Earth are accelerated differently. Gravitational acceleration is different at the center of the earth compared to the surface. And the centripetal acceleration is different at the equator compared to the poles. So if a creationist claims the Earth is stationary, ask him which part? If he says the center is still, then the surface must be rotating from west to east. And if he claims the surface is still, then that means the interior is rotating east to west. If he claims the whole earth is stationary, then he's talking nonsense with respect to relativity. (Gee, imagine a creationist talking nonsense...)

Moving beyond the earth other problems crop up. Contrary to the general view of the stationary earth model, all the heavenly bodies would not orbit the Earth; only the Sun and Moon would. Kepler's laws prove conclusively that the planets orbit the sun. And measurements of stellar motion show that the stars in our galaxy orbit the center of the milky way. So, for the geocentric model to work, the planets would orbit the sun as it orbits the earth, and the stars would orbit the galactic center as it orbits the sun as it orbits the Earth. Ask the creationist why does every other object in the universe orbit the Sun rather than the Earth if the Earth is the center?

It gets even weirder when you think about the distant stars and galaxies. As someone has pointed out, for a distant galaxy to orbit the earth once every 24 hours it would have to move faster than the speed of light, which would violate the theory of relativity. Now, there is a way around this seeming contradiction. If space were warped just right, you could make the fabric of space orbit the earth once each day, while the stars moved at their normal speed through space (analogy: imagine walking down the aisle of an airplane in flight: you are walking at 5kph while the plane flies at 300kph which gives you a speed of 305kph with respect to the earth). But consider the shape that space would have to have to wrap around the earth once each day. The shape of the fabric of space would be a spiral or pinwheel that wraps around the earth once for each day the earth has been here. Even in creationist math this would be 6000years times 365days = 2 million spirals.

So go out and look at any star in the sky. In the stationary earth universe, the apparent 'straight' line the light follows from the star to you is really a pinwheel path wrapped around the earth 2 million times. Make you dizzy? Sound like total nonsense? Well, that's the nonsense needed to make the stationary earth universe work.

Regards, Jim