Time for a bit of physics.

You are probably aware that we cannot currently account for about 95% of the matter in the Universe. Dark Matter and Dark Energy are the place holder names we use to describe the Missing mass and energy until such time as we find them, which I’ve no doubt we will in time.

What you may not know, however, is that, of the matter we do know about: most of that is missing, too (I know, it’s embarrassing). It is known as the Missing Baryon Problem. Baryons are simply the particles that matter is made of, your common to garden protons and neutrons plus some other more exotic particles that we don’t need to worry about here. You are made of baryons, your phone is made of baryons… you get the picture.

Simulations of the universe have long suggested that the missing matter might be strung out like bunting between the galaxies, the problem has been that this matter is too far away, too cold and too sparse for us to make it out. Until now.

Two separate teams, from the University of Edinburgh and The University of British Columbia, have both managed to empirically determine the presence of these intergalactic filaments to a confidence of more than 5σ. They did it by using a phenomenon known as the Sunyaev-Zel’dovich Effect. This is when light left over from the Big Bang, the cosmic microwave background, passes through hot gas and gets scattered leaving a darker patch when we image it.

The teams overlaid literally hundreds of thousands of images of pairs of galaxies to try to build up the signal between them. This sounds like it should produce some amazing photo that I could use here in the blog but unfortunately their analysis was all statistical so… no dice.

Anna de Graaf of the Edinburgh team estimates that the new findings could account for 30% of all the baryons in the universe. So, as well as not having the foggiest about Dark Matter and Dark Energy, about a third of everything we do know about is hidden away between the galaxies where it is all but impossible to see it. It sounds like there is still some work to be done on the final frontier.