CMBR image changed?

Question

How has the “image” of the CMBR changed over the past forty years?

Answer 1

The only changes to the CMB images are due to teh resolution of the observing instruments. The original 'image' was that from the Horn Antennae of Bell Labs. This was followed by not very successful high altitude observation attempts. The first, best image came from the COBE satellite and the most recent high resolution image came from the WMAPs satellite.

Answer 2

I WOULD GUESS: not substantially. I am not even sure we could even measure the changes. But I could be wrong and there might be an effect on the 40 year time scale. However... we have just made the first real precision measurement of the CMB and so we would have to wait for a while before we get another snapshot as good as the one from WMAP.

You have to keep in mind we are looking at the afterimage of something that has happened roughly 380.000 years after the initial second of the Big Bang. So the photons we see come from a process that has long stopped. However... these photons are running through an inhomogeneous background metric and there is gravitational lensing going on (in addition to simply other matter being between the source and us) and this does modulate the radiation in space and time.

Assuming that the modulation is on the same temporal time scale as the spatial modulation, my answer would be... nope. The changes will be way to slow for us to see. The finest spacial scale is, after all, around a tenth of a degree. So if you project that angle onto the circumference of the visible universe, we are talking on the order of a hundred billion lightyears * 0.1degree/360 degrees or something like 25 million light years. So I would venture that the temporal changes are modulated on the 25 million year scale.

But this is just a hunch. Someone from the field or with better information correct me.

Answer 3

Hi. Amansscientiae's answer is real good. I would think that the resolution is finer, on the order of a tenth of an arc-second. But I think that the only image change is due to better technology, not real change.