Perhaps we could call that thing: "dark matter" for now.
In seriousness, we can observe the effect, and even map the distribution of the stuff.
In seriousness, we can observe the effect, and even map the distribution of the stuff.
No, we can measure the dissonance between our best theories and reality. And make a conjecture about 'stuff'.
Give me a recent and well supported study indicating that dark matter may be something other than matter, and I'll happily read it.
My understanding is that the existence of dark matter is uncontroversial among physicists, and that the best bet is some sort of WIMP.
But it feels very strange to accept something that:
- is a particle
- doesn't interact with other normal particles (except through gravitation)
- doesn't interact with particles of its own kind
Maybe dark matter interacts with things via the weak force, but even less than neutrinos- not quite zero, but just small enough that we can't measure it, or can't measure it yet. Hopefully, they do interact a little bit by some other mechanism otherwise they'll be very hard to detect- I believe this is what current attempts to find dark matter are relying on.
But it's very very hard to come up with plausible models for such modified gravity. There are lots of people trying, and their ideas tend to break all sorts of other things we know. For example (IIRC) lots of candidates gave a slightly different speed for gravitational waves, and were ruled out by recent detections where we also saw X-rays from the same event.
It doesn't really work. Overwhelmingly the evidence points to mass, which is gravitationally affected by other mass, and nothing else.
I know the mind rebels against the notion of invisible matter, but is it really so much more implausible than the invisible spookiness of gravity to begin with? If the scientific evidence points that way, your monkey-brain intuitions do not provide a reliable veto.
Of course MOND can't really explain the third peak of the cosmic microwave background radiation, so it isn't perfect either. It is also phenomenological, with no underlying physical theory at the moment. Still, it's surprising that it does work at all.
I should also mention that the bullet cluster, which is touted as proving dark matter, causes issues for dark matter as well as MOND. The velocities involved in the collision are higher than can be explained by the current dark matter models. MOND kind of sucks at dealing with clusters, as well.
TL;DR MOND is a lot better than LCDM at explaining galaxy dynamics, LCDM is a lot better than MOND at explaining the cosmic background radiation. Both aren't that great at dealing with clusters (but you can also make dark matter work with enough fiddling).
https://tritonstation.wordpress.com/2018/09/04/dwarf-satelli...