New Theory Could Solve Universe’s Biggest Paradox

It could modify Einstein’s theory of general relativity — and kill the need for dark energy altogether.

more…

read that, then this..

https://www.theguardian.com/science/2020/jan/25/has-physicists-gravity-theory-solved-impossible-dark-energy-riddle

transition said:

read that, then this..

https://www.theguardian.com/science/2020/jan/25/has-physicists-gravity-theory-solved-impossible-dark-energy-riddle

I liked that one.

so now we have two new competing hypotheses, Massive Gravity and Emergent Gravity…

and….

“De Rham is quick to point out that at this stage, massive gravity is still just a theory. “

oh dear.

ChrispenEvan said:

and….

“De Rham is quick to point out that at this stage, massive gravity is still just a theory. “

oh dear.

I wonder if she really said that.

The Rev Dodgson said:

ChrispenEvan said:

and….

“De Rham is quick to point out that at this stage, massive gravity is still just a theory. “

oh dear.

I wonder if she really said that.

still, it is quite a usual way of saying it. not correct but common

The Rev Dodgson said:

ChrispenEvan said:

and….

“De Rham is quick to point out that at this stage, massive gravity is still just a theory. “

oh dear.

I wonder if she really said that.

Google finds 56 hits on the exact phrase:
“De Rham is quick to point out that at this stage, massive gravity is still just a theory”

ChrispenEvan said:

The Rev Dodgson said:

ChrispenEvan said:

and….

“De Rham is quick to point out that at this stage, massive gravity is still just a theory. “

oh dear.

I wonder if she really said that.

still, it is quite a usual way of saying it. not correct but common

Quite usual amongst the proletariat, but I thought actual scientists would avoid it.

The Rev Dodgson said:

The Rev Dodgson said:

ChrispenEvan said:

and….

“De Rham is quick to point out that at this stage, massive gravity is still just a theory. “

oh dear.

I wonder if she really said that.

Google finds 56 hits on the exact phrase:
“De Rham is quick to point out that at this stage, massive gravity is still just a theory”

The Guardian seems to be the first one.

Others have just quoted bits without reference, or nicked the whole article.

The Rev Dodgson said:

ChrispenEvan said:

The Rev Dodgson said:

I wonder if she really said that.

still, it is quite a usual way of saying it. not correct but common

Quite usual amongst the proletariat, but I thought actual scientists would avoid it.

well maybe they mean it’s just theoretical, and it’s up to us to make practical use of it

Tau.Neutrino said:

New Theory Could Solve Universe’s Biggest Paradox

It could modify Einstein’s theory of general relativity — and kill the need for dark energy altogether.

more…

Dark energy isn’t a mystery or paradox. Einstein solved it 100 years ago. Cosmological constant.

>instead of assuming that gravitons, the hypothetical particles responsible for the force of gravity, are massless, as Einstein did, she suggests that they do have some mass.

You do understand that gravitons are incompatible with general relativity, right, unless there are an infinite number of them that amazingly cancel out each other’s effects.

mollwollfumble said:

Tau.Neutrino said:

New Theory Could Solve Universe’s Biggest Paradox

It could modify Einstein’s theory of general relativity — and kill the need for dark energy altogether.

more…

Dark energy isn’t a mystery or paradox. Einstein solved it 100 years ago. Cosmological constant.

>instead of assuming that gravitons, the hypothetical particles responsible for the force of gravity, are massless, as Einstein did, she suggests that they do have some mass.

You do understand that gravitons are incompatible with general relativity, right, unless there are an infinite number of them that amazingly cancel out each other’s effects.

No, I don’t understand that. Can you amplify?

(Not saying you are wrong, I have no idea).

The Rev Dodgson said:

mollwollfumble said:

Tau.Neutrino said:

New Theory Could Solve Universe’s Biggest Paradox

It could modify Einstein’s theory of general relativity — and kill the need for dark energy altogether.

more…

Dark energy isn’t a mystery or paradox. Einstein solved it 100 years ago. Cosmological constant.

>instead of assuming that gravitons, the hypothetical particles responsible for the force of gravity, are massless, as Einstein did, she suggests that they do have some mass.

You do understand that gravitons are incompatible with general relativity, right, unless there are an infinite number of them that amazingly cancel out each other’s effects.

No, I don’t understand that. Can you amplify?

(Not saying you are wrong, I have no idea).

OK. There’s a marvellous book called “Quantum Field Theory in a nutshell” by A. Zee.

One of the great things about this book (apart from it being neither too difficult to understand nor too simplified to be useful) is that it actually starts with advanced and extremely interesting topics.

The unification of gravity and quantum field theory begins in chapter 1.5. This chapter introduces the photon as a spin 1 particle and shows that like electric charges must repel. Next the chapter introduces the graviton as a spin 2 particle and shows how quantum mechanics insists that gravity must attract.

However, page 35, the strength of attraction of the graviton in quantum mechanics is shown to be 4/3 times the strength of gravity in general relativity. This is the well known fundamental incompatibility of quantum mechanics and general relativity.

Introducing multiple gravitons can change that factor of 4/3 but only at the expense of each new class of graviton introducing new terms that would need cancellation. Hence the need for an infinite number of gravitons to be consistent with GR, and even then the situation is such that no known infinite set of gravitons will suffice.

Chapter 1.6 in “Quantum Field Theory in a nutshell” by A. Zee introduces Brane worlds and Planck mass.

All this before the book turns to Feynmann diagrams in Chapter 1.7.

mollwollfumble said:

The Rev Dodgson said:

mollwollfumble said:

Dark energy isn’t a mystery or paradox. Einstein solved it 100 years ago. Cosmological constant.

>instead of assuming that gravitons, the hypothetical particles responsible for the force of gravity, are massless, as Einstein did, she suggests that they do have some mass.

You do understand that gravitons are incompatible with general relativity, right, unless there are an infinite number of them that amazingly cancel out each other’s effects.

No, I don’t understand that. Can you amplify?

(Not saying you are wrong, I have no idea).

OK. There’s a marvellous book called “Quantum Field Theory in a nutshell” by A. Zee.

One of the great things about this book (apart from it being neither too difficult to understand nor too simplified to be useful) is that it actually starts with advanced and extremely interesting topics.

The unification of gravity and quantum field theory begins in chapter 1.5. This chapter introduces the photon as a spin 1 particle and shows that like electric charges must repel. Next the chapter introduces the graviton as a spin 2 particle and shows how quantum mechanics insists that gravity must attract.

However, page 35, the strength of attraction of the graviton in quantum mechanics is shown to be 4/3 times the strength of gravity in general relativity. This is the well known fundamental incompatibility of quantum mechanics and general relativity.

Introducing multiple gravitons can change that factor of 4/3 but only at the expense of each new class of graviton introducing new terms that would need cancellation. Hence the need for an infinite number of gravitons to be consistent with GR, and even then the situation is such that no known infinite set of gravitons will suffice.

Chapter 1.6 in “Quantum Field Theory in a nutshell” by A. Zee introduces Brane worlds and Planck mass.

All this before the book turns to Feynmann diagrams in Chapter 1.7.

Thanks Moll, I’ll have a look for it.

My initial reaction to the article was: how come no-one thought of this before, to which the answer seems to be, they did, but the maths didn’t work.

Apparently she has come up with some new maths, which does work, so I wouldn’t dismiss it just yet.