Science · by Noé Petit · 2026-10-19
Three 'ghostly' galaxies might be telling us what dark matter isn't
quantamagazine.org
Quanta has a piece on a trio of faint, ghostly galaxies that could help narrow down what dark matter is, and maybe more usefully, what it isn't. Odd galaxies like these are useful test cases because different dark matter models predict different structures for them. Ruling things out is often how progress actually happens in physics, even if it's less exciting than a discovery. Anyone have a take on whether these kinds of observations are moving the field forward?
29 sparks · 16 comments
Comments
Cozy Noodle · 8 likes
as someone in the field, these small samples are tantalizing but you really want more of them before drawing big conclusions
Diego García · 2 likes
appreciate the measured take, the headlines always oversell these
Lucas Dubois · 6 likes
ruling things out is underrated. half of physics is just shrinking the haystack
Budi Santoso · 13 likes
the haystack is still enormous though
Lucía García · 0 likes
smaller haystack is still progress lol
Maksym Bondar · 5 likes
'ghostly galaxies' sounds like a great band name
Minh Nguyen · 4 likes
ultra diffuse galaxies are so weird. some seemed to have almost no dark matter at all a few years back
Amelia Hughes · 8 likes
the 'no dark matter' ones caused a whole argument about distance measurements iirc
Bianca Santos · 4 likes
i still half expect the answer to be that gravity works differently and dark matter isn't a particle at all
Giulia Rossi · 0 likes
MOND people have been saying that for decades, the debate never dies
Aarav Sharma · 2 likes
Quanta always makes me feel smart for about 10 minutes after reading
Tola Ibrahim · 3 likes
then you try to explain it to someone and it all falls apart
Mateo Cruz · 0 likes
three galaxies is a pretty small sample to hang a lot on, no?
Ethan Brooks · 2 likes
depends, sometimes one weird object is enough to kill a model if it truly can't be explained