The 20th century was the century of weird physics. Weird, mind you, is in the eye of the beholder. Sure, general relativity or quantum mechanics were strange at first, but today, the ideas of invariance, general covariance, or commutator algebras are not at all illogical. More importantly, they work: the predictions of “weird” physics are fully confirmed by experiment.
In contrast, it seems that the physics of the early 21st century is increasingly phantom physics. First, we were told that five sixths if the matter content of the universe is “cold dark matter”, stuff that is invisible and undetectable, as it only interacts with normal matter and with itself gravitationally. Then we were told that all the matter (including dark matter) that is out there is only 30% of the total energy content of the universe, 70% is even more invisible, even more undetectable “dark energy”.
Meanwhile, particle physicists trying to deal with the possibility that the much anticipated Higgs particle will remain undiscovered are toying with the idea that additional particles (which themselves may not be detectable) may cancel out the Higgs boson’s contributions, and thus the Higgs boson would never be detectable. In other words, if I am reading this right, one possibility is that the non-observation of one undetectable particle will be viewed as proof of the existence of another unobserved particle. Wow!
And then I have not even mentioned other undetectable stuff, such as superstrings (too small to ever become detectable by any conceivable experiment), unification (expected to occur at the Planck energy scale, which is forever unreachable by observation), unparticles (yes, there are such animals in the land of theoretical physics), “phantom” matter and energy (I am not making this up), not to mention all the parallel universes of the string theory “landscape”, some of which are populated by “Boltzmann brains” that exist all by themselves, contemplating their existence and inventing imaginary universes around themselves.
I think I prefer the “weird” physics of the 20th century. At least that physics was firmly rooted in what physics is supposedly about, observation and experiment.