As I understand it, dark matter and dark energy are just placeholders for discrepancies between our current physical model and observations made by telescopes like Hubble and Kepler. This could mean either that our measurements are inaccurate, or that the model is incomplete. Honestly, I think that both are extremely likely.

Dark matter (matter that has mass but does not interact in any other way) might be the literal solution. But there are also other suggestions (MOND is a big one).

The https://en.m.wikipedia.org/wiki/Bullet_Cluster is pretty interesting.

"Dark matter" and "dark energy" could just as well be called "unexplained matter" and "unexplained energy".

These terms are mostly placeholders for things we don't understand.

not even that. "unexplained matter" implies that there is some matter to explain (what type etc) when in reality is an unexplained observation that could be explained by current laws/constants if only there was some more (actually a lot more) matter. is a pure mathematical construct and mathematically it wold be just as valid to ad "dark constant modifier"

I think they can also just be an unknown phenomena. They don't need to be literal mass or energy. Essentially, to fit our current model to observations of how our galaxies and the universe in general behave, we need to add mass and energy to the equation to make it match. Essentially, dark matter and dark energy are fudge factors to get our models to work.

There are a ton of theories to reconcile the differences, but very few are provable with our current techniques. Detecting literal dark matter is one possibility. Changes in universal constants would be another.

Our understanding of the laws of the universe is incomplete either way. If dark matter exists, we still don't know what it's made of or exactly what properties it has.

> So is there really dark matter and dark energy, or is our understanding of the laws of the universe incomplete?

These propositions are not mutually exclusive, the former implies the latter, right?

The mainstream thought is that they are real and undetected, but there are theories that they aren't and there's plenty of attempts to modify laws to explain them away (and I suspect there's some wistful thinking that there's maybe a Noble prize there, so there's already been a fair bit of work done, even though it's very controversial).

To be fair, the last time someone explored a discrepancy between known physics and empirical observation we got quantum mechanics and relativity. There is a commonly held belief that as observations outpace theory that we'll have a similar leap in technology. I think this is why everyone was so excited about the LHC and Kepler Observatory.

I don't know whether the next breakthrough in physics will be quite as relevant in our lives as quantum and relativistic physics. It would be nice if we could link gravity and E/M like we did with the strong and weak forces. Who knows what we could do if we knew how those two go together.

Many, many, many scientists have asked this question. Many have made careers out of arguing the case.

But, the overwhelming majority of scientists that start out asking those questions ultimately land on the mainstream theories around dark matter and dark energy being our best, most consistent, and broadest ranging answers.

If someone were to come to them with a better theory that could explain more completely the sum total of these observations they would almost certainly be open minded about it.

So... is there really dark matter and dark energy? Probably. We've got a whole lot of evidence that isn't explained better by any alternatives. But I doubt any of these scientists would say it's totally impossible.

Yes of course, it's the best theory we currently have. Also Newton's gravitational theory was the best explanation until someone came with a paradigm shift that explained the observations better. And we seem to be quite stuck with the current theories, so I suspect we might need another paradigm shift.

I'm not sure the SR is really that large of a paradigm shift.

All Einstein did, I know that conceptually this was a large leap and just saying "all he did" is doing him a severe disservice for his contributions, is note that the mass of an object is dependent upon the speed of the object. Such that for velocities that are not an appreciable fraction of c we can use Newton's laws of gravitation perfectly well.

TLDR; Einstein did not replace Newton, he tweaked him.

Newton's gravitation is still pretty relevant today. Only in special circumstances is relativity necessary. I wonder if Dark Matter and Dark Energy will be just as relevant in the future?