Most science-based “fact” is technically “theory.” Most is “proven.” Math is the only thing that is 100%. 2+2=4. That’s a fact. Chemistry could fall into the 100% category too,as long as the chemistry has already been tested.
Everything else is theory. But it has gone the scientific method route. So the “fact/law/theory” started as a hypothesis, then was later shown through testing,observation,and scrutiny of scientific peers to be correct. But many hypotheses are proven by statistics. If you do x and y, then z usually occurs….
Medical science is kind of scary. Some drugs are effective in treatment, but the exact scientific reason is unknown/undiscovered.
Science is trial and error. Often scientific “fact” will be overturned , or debunked…
I have read several articles about space that mention that either the laws of gravity differ in some places, or our understanding of gravity is flawed. As some celestial calculations don’t add up.
So either certain celestial observations mean things are cheating/not behaving according to the laws of gravity, or we have the math wrong…