Abstract

Observations on galactic scales reveal an acceleration discrepancy: a mismatch between predicted and observed values, when applying Newton’s Law of Gravity (the Inverse Square Law) to observed mass. The existence of dark matter is therefore inferred. Unsurprisingly, it always works. But is it right? Null detection at the LHC and other direct searches for the particle make this increasingly unlikely. This lecture will show why vast amounts of dark matter combined with purely Newtonian gravity is not the most likely explanation from an Astrophysical point of view either. Rather, it is the assumption of Newtonian gravity that probably fails at ultralow accelerations. This is likely due to quantum effects, which are ignored in our theories of gravity but usually become important when the numbers are small.