Perhaps a silly analogy - hologram light source retreating?

[SteveSA]

Hi everyone

I would love to get some feedback on this silly idea I had when thinking of the balloon analogy.

Another way to achieve the same effect - at least in 2 dimensions - is to move a projector further away from a screen - everything expands relatively.

If the universe is a 2d hologram - could not the appearance of expansion be caused by some lensing effect at the source of the hologram? For instance - if the source of the hologram was retreating/shrinking, or expanding, could that not effect the measurements of universal expansion?

Please be gentle - I am just a lawyer.

Cheers

Steve

 

[PeterDonis]

Hi @SteveSA and welcome to PF!

I would love to get some feedback on this silly idea I had when thinking of the balloon analogy.

You should be aware that the balloon analogy is only an analogy and has some serious limitations. We have had previous PF threads on this, which should be findable using the PF search feature.

If the universe is a 2d hologram - could not the appearance of expansion be caused by some lensing effect at the source of the hologram?

Unfortunately this can't be answered because we don't have any theoretical model of the universe that works like this. The observation that "the universe is expanding" is not a simple observation: it involves measurements of a number of different observable quantities (redshift, brightness, and angular size of distant galaxies are the three main ones) for many, many different galaxies. Our current cosmological model has to successfully account for all of these observations. In order to assess your idea, we would need to have a model based on it that could be tested to see if it can also account for all of those observations. Just "the appearance of expansion" is not enough.