How do we know Einstein has it right?

Question

We constantly say that Einstein’s General and Special theories of relativity have passed many different tests, insenuating their accuracy.

Before Einsten, we tested Isaac Newton’s theories, which also passed with accuracy until Einstein came along.

What’s to say another Einstein/Newton comes along 200-300 years from now to dispute Einstein’s theories?

Is that even possible or are his theories grounded in certainty at this point?

In: 593

Answer 1

Theories are never a certainty; they only survive the most recent round of testing, or not.

We actually already know that Einstein wasn’t completely right. Relativity is a so-called “classical theory”, meaning it doesn’t take quantum effects into account. We know quantum effects are real, and relativity can’t deal with anything on the quantum scale. Some very smart researchers (or teams of researchers) will have to come up with a way of creating a theory of quantum that correctly describes relativistic effects, but they haven’t been able to so far.

Of course, that is not to say theories aren’t useful. They are the best tool we have for describing and explaining certain situations. In that regards, Newton was ‘right’ – in the realm of what Newton tried to describe, his laws of motion work perfectly. It is only when you try to describe extreme situations like objects moving at near the speed of light, that they break down. Newton had no clue about the speed of light. It was something between a few hundred kilometers per second and literally infinite.

Technically it is better to use Einsteins relativistic laws of motion instead of Newtons when describing medium events, i.e. objects of medium weight moving at medium speeds (reminder that an object like the Sun has a ‘medium weight’), but the difference would be so far down in the decimal places that practically you can just use Newton.

If you collide 2 objects and the result is an object moving at 20 m/s according to Newton and 19,99999998 m/s according to Einstein, for example, and the math for Newton is much easier, why bother with Einstein in that scenario?