“The Standard Model (of particle physics) is inconsistent with that of general relativity, to the point that one or both theories break down under certain conditions…”
From Wikipedia– https://en.wikipedia.org/wiki/Physics_beyond_the_Standard_Model
The vacuum catastrophe is sometimes cited as the biggest disagreement between theory and experiment ever.
They disagree by a factor of at least 10107.
According to quantum field theory the energy of empty space can’t quite be zero. In fact, QFT gives us an exact value for how much energy empty space should have. Although we can never access that energy, it does have a gravitational effect.
One of the (many) things the Voyager probes did was allow us to estimate how strong those gravitational effects are. Unfortunately, they determined that the theoretical predictions are way, way, way off (too high).
There’s a short paper here aimed at the undergraduate physics crowd that covers this better than I do. //