If gravity affects light, then can it affect the wavelengths of light.

Gravity does affect the wavelength of light, sort of. It only happens near the gravitational object. The reason is that the wavelenght of light actually does not change. What changes is the space-time continum that the light travels through. An object is going to cause the space-time continum aournd it to stretch and makes the light wave travling through that stretched space-time look like the wavelength has changed. However, as soon as the light wave leaves the affected area, the wavelenght chage illusion will be gone. So from far way, this warping of the space-time continum will cause the light wave to bend around the object (ie gravitational lensing) but will not actually change the acutal wavelength of the light.

That I suppose is the key question in theories of everything, GUTs, quantum gravity. Rather the focus in popular literature has been on the very very small, that is, how the atom appears in terms of the influence gravity has on it. The truth as you suggest may be more noticeable in the case of light from distances that cross inter-galactic space-time. There in the impossibly huge gap in the existence of (light) or radiant matter, may lay the answers to dark matter. It should have a balancing tendency of the near (negative) direction of gravitational attraction.

>If gravity affects light, then can it affect the wavelengths of light.?

Absolutely. There is a phenomenon known as 'gravitational redshift' (if I recall correctly) which is essentially what you're suggesting here.

>Therefore, the way we measure the chemical makeup of far away things in space, has to be slightly or even greatly in error because of light absorption errors from wavelength changes.

We have known about this effect for a long time, and make sure to correct for it in our calculations. Scientists are not that careless.

Gravitational redshift or Einstein shift is the process by which electromagnetic radiation originating from a source that is in gravitational field is reduced in frequency, or redshifted, when observed in a region of a weaker gravitational field.

No, gravity cannot affect the wavelengths of light because light travels through electromagnetic radiation, not a medium. Because waves travel through space which is an essential vacuum, I do not believe gravity would affect something that is not a physical object.

Wrong track - as you switch from measurable shift to absorption in the middle of your paragraph. Different things and the differences are detectable and known. 10,000 astronomers have looked at this before you "discovered" the "error"

wrong track son