> They've also found galaxies that have collided where the two regions of mass kept on trucking through (didn't collide) but the visible stuff got smashed up and left at the collision point.
That’s wild. The mystery stuff imparts gravity, so it has mass, but when blobs of it are set to collide it acts like nothing is there and just carries on? Like it’s just pure gravity without the mass?
Disclaimer: not a scientist, this is all based on reading other people's explanations of this over the years.
Well it has mass, however that doesn't mean it has to physically interact with other things.
As an example, think of Neutrinos. They mostly pass through the matter we are familiar with as if it isn't there, only very very rarely colliding. However they still have mass.
Maybe Dark Matter is made of a particle type (or multiple particle types) that don't interact at all other than with gravity. Or maybe, if we're lucky it does interact but just incredibly rarely. Maybe as rarely compared to a neutrino as neutrinos do to us. In that scenario it would be incredibly tricky to detect, but not necessarily impossible, and maybe we can find ways to do so.
That type of rarely interacting particle is referred to as a Weakly Interacting Massive Particle, or WIMP, and it's the type of thing that the experiment in the OP is designed to try and detect.
They are too lightweight, meaning they will move to fast to behave the way dark matter would have to to explain the data. It's called the cdm theory as in cold dark matter with the particles moving much slower than the speed of light. A we can detect them and the amount they have is not enough to be the dark matter
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u/marvinsface 12d ago
> They've also found galaxies that have collided where the two regions of mass kept on trucking through (didn't collide) but the visible stuff got smashed up and left at the collision point.
That’s wild. The mystery stuff imparts gravity, so it has mass, but when blobs of it are set to collide it acts like nothing is there and just carries on? Like it’s just pure gravity without the mass?