Unlike Einstein's Relativity,
Quantum Mechanics is just a bundle of statistics from heaps of data
― it's predictive, but semi-random, incomplete.
Relativity is predictive And fully complete, sans randomness.

Perhaps objects vibrate faster at lower altitudes,
thus warping spacetime ― and our simple/3-D minds model it as a force.

When a muon from a cosmic ray ― moving near the speed of light ―
hits you, its momentum is very real, not “ notional ”.
In fact, it'd have infinite momentum, if it could move at c.

Likewise, its slower tick-rate is real, not notional.

Muons are natural clocks ― we know how long they live ―
and we know that ― to us humans ― they live longer when
moving near the speed of light.