Weak gravitational lensing provides significant evidence for dark matter, yet it is not definitive proof. The discussion highlights that while the Bullet Cluster offers compelling support against Modified Newtonian Dynamics (MOND), experts remain divided on the sufficiency of current evidence. The complexity of alternative theories, such as MOND, complicates their acceptance, especially given their challenges in aligning with Cosmic Microwave Background (CMB) data and galaxy cluster observations. Thus, while weak gravitational lensing is a strong indicator, it does not eliminate the possibility of alternative explanations.
PREREQUISITESAstronomers, astrophysicists, and students of cosmology interested in the ongoing debate surrounding dark matter and alternative theories such as MOND.
Apparently, since all of that has been known for some time and still dark matter is not 100% guaranteed to not be MOND. I thought the Bullet Cluster was enough evidence against MOND but more knowledgeable folk than me think otherwise.wolram said:Do we need more proof of dark matter than this?:
https://en.wikipedia.org/wiki/Weak_gravitational_lensing
It turns out that when you only have one general class of evidence for a model (in this case, gravitational interactions), it's remarkably difficult to completely rule out alternative explanations. My understanding is that alternatives to dark matter are not very well-motivated by theory and tend to be much more complicated than many WIMP models. It also turns out to be much harder to get a modified gravity theory to work well with CMB, galaxy clusters, and galaxies using the same parameters (MOND has always had difficulty fitting CMB and cluster data).phinds said:Apparently, since all of that has been known for some time and still dark matter is not 100% guaranteed to not be MOND. I thought the Bullet Cluster was enough evidence against MOND but more knowledgeable folk than me think otherwise.