What if Einstein is wrong about gravity?

[andy2]

In order for Einstein to be right, there has to be dark matter but nobody so far has been able to detect dark matter. There are competing theories that modify our understanding of gravity, but they are at best incomplete.

There are situations where dark matters are better suited, whereas others where modified gravity are better suited to explain.

I think it all comes down to our human inability of understanding the worlds. Quantum theory and general gravity are both incomplete.

These two videos serve as a short summary of dark matter vs. modified gravity.

Dark Matter: The Situation has Changed - YouTube

What If Our Understanding of Gravity Is Wrong? - YouTube

 

[Galu]

These matters have been discussed, and are still open for discussion, over on the "Universe" thread.

Feel free to join us there guys if you have anything new to offer to the discussion.

 

[Disco-Pete]

Perhaps someone on the "other side" might change the title? After all, there's a lot involved in the expansion of the Universe, right? There are toes out there far bigger than the mere notion of a "universe". 🙂

 

[planet10]

Particle physics, cosmology, are finding many things that led me to believe that our model of the physical world and the universe is about to go thru significant evolution/change.

The new telescope will bring even more i expect as will more sensitiy gravity detectors being assembled.

dave

 

[Bonsai]

Einstein explained how gravity really works and his equations are surprisingly accurate. He did not explain the fundamental underlying mechanism. That’s something that’s still being debated/researched.

It’s the same with Maxwell's equations. Amongst the most accurate in all of physics, but there is still no rational explanation for how a photon propagates across the universe other than ‘it’s an EM field’. Go onto any professional physics forum or try physics.org and ask the question. They’ll throw Maxwell’s equations at you, but keep asking insistently and eventually the truth comes out ‘well, we don’t actually know’.

In both of these cases, it does not invalidate the scientists work, or mean that they were wrong.

🙂

 

[Galu]

When new observations are made that are incompatible with a theory, scientists either have to admit they've got the rules wrong or they have to accept that something else is at play that they haven't previously considered.

When it comes to the observed fact that gravity does not affect the matter we can see in the Universe in the way predicted by the theory of General Relativity, most scientists don't want to alter the rules of the theory, but would rather introduce the previously unconsidered idea of Dark Matter to explain the gravitational discrepancies.

However, some scientists favour the alternative of considering that our current theory of gravity breaks down on larger cosmic scales and has to be modified (Modified Newtonian dynamics or MOND).

Both approaches have their weak points and we still have a long way to go to fully understand gravity on the cosmological scale.

 

[Disco-Pete]

Fully understanding gravity results in the "theory of everything", no?

 

[Galu]

You must have gleaned that over on the Universe thread, Pete! 😉

 

[Disco-Pete]

Absolutely NOT!
pure logic 😎

 

[NickKUK]

I believe Einstein was wrong about a lot of things, only the ones that carried favour in propelling others research grants were deemed right 😉

I know from my limited time being involved with quantum research:
* there are things you know and can poke it with a screwdriver
* there things that can be observed and logically make sense as part of things we know
* there are things that we're guessing blindly about that we think we know.
* there are things we don't even see, understand or can poke.

The shocking realisation is each category on that list is exponentially larger than the one before - including the brain processes of reality TV.

Now model that to psychological perspective of being in control, through to being out of control.. sometimes not seeing the scale of the unknown is a good thing.

 

[NickKUK]

Einstein explained how gravity really works and his equations are surprisingly accurate. He did not explain the fundamental underlying mechanism. That’s something that’s still being debated/researched.

It’s the same with Maxwell's equations. Amongst the most accurate in all of physics, but there is still no rational explanation for how a photon propagates across the universe other than ‘it’s an EM field’. Go onto any professional physics forum or try physics.org and ask the question. They’ll throw Maxwell’s equations at you, but keep asking insistently and eventually the truth comes out ‘well, we don’t actually know’.

In both of these cases, it does not invalidate the scientists work, or mean that they were wrong.

🙂

Quantum Gravity...

However you're right - nobody has explained what the fields are, how mechanisms occur nor why they exist.

To quote Rudyard Kipling - Who, What, Why, When and Tell me about..

 

[indra1]

Fully understanding gravity results in the "theory of everything", no?

Sorry Pete, but fully understanding anything simply means we successfully pass another door that leads to other doors. We are still a long way from the end of the path. 🙂

 

[andy2]

In the early day when the prevailing theory that the earth was the center of the solar system, "scientists" in those days actually had equations that predict the motion of the planets fairly accurately.

Same thing now that GR can accurately predicts things but the underlying understanding of gravity may not be true.

 

[kevinahcc20]

There is no "underlying understanding of gravity" whatsoever, just a newer set of equations that better map to all observations than Newton's did. Of course Newton's equations work just fine for the vast majority of terrestrial physics and they are still used for most Earthbound engineering.

 

[Galu]

Of course Newton's equations work just fine for the vast majority of terrestrial physics and they are still used for most Earthbound engineering.

And they were certainly adequate enough to send astronauts to the Moon.

 

[andy2]

The fundamental philosophical question to ask is if humans are capable of understanding the true nature universe. We can get close but not quite there. Quantum physics and General Relativity are just an approximation of reality, but not reality in itself. This question was asked way back from the time of Plato (his cave men depiction).

Newtonian gravity is just an approximation but good enough for most stuffs within the solar system.

 

[WhiteDragon]

I might be able to prove dark matter.

Just spend a day or 2 with my Ex Girlfriend.

Far as the experiment being repeatable
3rd day will have 98.6% probability as being just as dark

 

[system7]

Way I see it, is we are on the inside looking out. Where we want to be is on the outside looking in. But this is impossible, because we can't see beyond the Big Bang and the Cosmic Microwave Background.

Two uniquely impenetrable theories rolled into one here, I don't make this up. Black Holes are made of Dark Energy Stars? 😕

Are Black Holes Actually Dark Energy Stars? - Facts So Romantic - Nautilus

Really, we need New Physics. That's it. Now don't get me onto whether Mr. Einstein's Space-Time might have two dimensions of time. Must dash. 😀

 

[Bonsai]

There is no "underlying understanding of gravity" whatsoever, just a newer set of equations that better map to all observations than Newton's did. Of course Newton's equations work just fine for the vast majority of terrestrial physics and they are still used for most Earthbound engineering.

There is a lot of work going on to try to understand how gravity emerges and what it is exactly. QLG is mentioned earlier in the thread, then there’s Entropic or emergent gravity that Erik Verlinde is working on.

Then there’s ‘gravitons’ - seems the particle physicists will always look for a ‘particle’ to explain stuff with.

 

[Disco-Pete]

Way I see it, is we are on the inside looking out. Where we want to be is on the outside looking in.

Seems to me this is the conundrum preventing our ability to do anything but theorize. We will never actually figure anything "out".