Has physicist's gravity theory solved 'impossible' dark energy riddle?

www.theguardian.com ^ | Sat 25 Jan 2020 06.40 EST | Hannah Devlin Science correspondent

[Red Badger]

Prof Claudia de Rham’s ‘massive gravity’ theory could explain why universe expansion is accelerating

Cosmologists don’t enter their profession to tackle the easy questions, but there is one paradox that has reached staggering proportions.

Since the big bang, the universe has been expanding, but the known laws of physics suggest that the inward tug of gravity should be slowing down this expansion. In reality, though, the universe is ballooning at an accelerating rate.

Scientists have come up with a name – dark energy – for the mysterious agent that is allowing the cosmos to expand so rapidly and which is estimated to account for 70% of the contents of the universe. But ultimately nobody knows what the stuff actually is.

“It’s the big elephant in the room,” says Prof Claudia de Rham, a theoretical physicist at Imperial College. “It’s very frustrating.”

Change could be afoot. De Rham has pioneered a radical theory that could hold the key to why the universe is expanding faster and faster and explain the nature of dark energy. The theory, known as massive gravity, modifies Einstein’s general relativity, positing that the hypothetical particles (gravitons) that mediate the gravitational force themselves have a mass. In Einstein’s version, gravitons are assumed to be massless.

If gravitons have a mass, then gravity is expected to have a weaker influence on very large distance scales, which could explain why the expansion of the universe has not been reined in.

“One possibility is that you may not need to have dark energy – or rather, gravity itself fulfils that role,” says De Rham.

The work marks a breakthrough in a century-long quest to build a working theory of massive gravity....

[edwinland]

... if this man’s theory is proven correct.

doh!

[mjp]

the hypothetical particles (gravitons) that mediate the gravitational force themselves have a mass. In Einstein’s version, gravitons are assumed to be massless.

Gravitons carry discrete amount of energy and energy has mass.

[from occupied ga]

yes, but WHY?

If I knew that I'd be in the physics business figuring out how many angels could dance on the head of a pin.

[Gamecock]

Just give up sex and you can do anything. Even learn Portuguese!

[reed13k]

ok....maybe a balloon expanding would have been a better example....hmmm

[Crucial]

Gravitons themselves have mass? No, I don’t think so.

[Red Badger]

Gravity may be the weakest, but it is still pretty powerful. It keeps us tied down................🤓

[Thommas]

“This man” is a a pretty attractive female..

[SunkenCiv]

Thanks Red Badger.

---

· String Theory Ping List ·

---

---

· Join · Bookmark · Topics · Google ·
· View or Post in 'blog · post a topic · subscribe ·

---

[Moonman62]

Change could be afoot. De Rham has pioneered a radical theory that could hold the key to why the universe is expanding faster and faster and explain the nature of dark energy.

...

If your theory isn’t doing well with other scientists, go to mass media.

[FLT-bird]

“Dark Energy”, “Dark Matter”....,,,,whenever you hear the word “dark” in a scientific context, you should immediately be suspicious. Those are just placeholders put n to explain why observations do not match our latest theory. Maybe.....just maybe.....the theory has some things wrong. Einstein obviously got a lot right. It was an advance over Newton who was an advance over superstition and dogma, but....maybe General Relativity is not a complete explanation.

[DivineMomentsOfTruth]

There is no edge.

[The Duke]

As it stands now it is merely a construct to attempt to explain what they do not understand”

Also known as “science of the day”

Or .. "fudge factor" :)

[null and void]

That hasn’t worked for me so far...

[Red Badger]

Which brings up the question, "If the Universe is everything there is, and it's expanding, what is it expanding into?" ................🤔

[RonnG]

Greta just tweeeted that the world has only 11.5 billion lights years left

[DivineMomentsOfTruth]

That, young grasshopper, is beyond our human ability to comprehend.. It's best that way.. for now. 😉

[TXnMA]

Prof Claudia de Rahm:

[Red Badger]

She can keep me after school anytime!!!!!!!..........😉

[Red Badger]

I think they are all connected................