Hacker News Reader

Think of it this way:

The laws of physics don't form a complete (fully connected) graph. Not every force (edge) affects every particle (vertex). Electrons and photons (obviously) affect each other, electrons and protons do the same (through the electromagnetic field, for example), but photons and neutrinos do not.

Why should we assume that the overall graph has only a single connected component?

View on HN

But (the hypothetical) dark matter does interact with regular matter through gravity, so your graph is connected.

The existence of 100% non-interacting particles is by definition non-falsifiable, therefore scientifically irrelevant.

Dark matter may be just normal matter that we can’t see because it’s too cold, WIMPs are not the only candidate for dark matter, if anything they are the weakest one currently since we’ve been finding more and more brown dwarfs and even massive ones.

I think the conventional explanation is that there are way too few lensing observations for normal matter to be anywhere near enough. You might read a news article that says there is 30% or 10 times more regular matter than we thought, but it's such a small baseline it doesn't make much difference to the big picture.

Reply on news.ycombinator.com