What is really behind the Universe - Art and Science, an LMAC Special - Teaming up with STEMsocial

What is really the "dark matter"? Maybe it is not dark but light and we know it for a long time.

This is my collage for the contest:

The resources I used (public domain):

https://stock.adobe.com/images/rome-italy-august-31-2021-the-painting-of-michael-archangel-in-the-church-santa-maria-della-concezione-dei-cappuccini-by-guido-reni-1636/462880357

https://stock.adobe.com/123921952?tduid=a5512937f9eeb871cd72313a516de30d&as_channel=affiliate&as_campclass=redirect&as_source=arvato

And two photos I personally made of the icons I own: