Here’s a good simple explanation. We can say exactly what causes gravity and describe it mathematically. That’s far different than the resurrection IMO.
Our understanding of the universe is constantly improving.
“The gravitational constant is a fundamental constant of physics, so it is important to test this basic assumption using objects at different places, times, and gravitational conditions. The fact that we see gravity perform the same in our solar system as it does in a distant star system helps to confirm that the gravitational constant truly is universal.”
Being a weak force, it is incredibly hard to measure and most methods to measure it have been deemed obsolete. Even the best method to measure it is certain to have undiscovered systematic errors.
Yes, matter. Since we are talking about Einstein, the theory of relativity (if it’s true) suggests that the universe had a beginning. A beginning where space, time, and matter did not exist.
I believe I read an account that Einstein himself was deeply troubled by this, since it kind of suggest there is something more…maybe a God. Of course there are many scientific theories on what was before space, matter, and time. Some of them more out there than others.