String theory is dead

String theory is dead.
arxiv.org/abs/1801.08160

Other urls found in this thread:

arxiv.org/abs/1801.08160
en.wikipedia.org/wiki/Parsec
sciencenews.org/article/gravity-doesnt-leak-large-hidden-dimensions
en.wikipedia.org/wiki/Five-dimensional_space
youtu.be/eN24Sv0qS1w
desuarchive.org/r9k/thread/18929562/#18929722
twitter.com/SFWRedditGifs

Elaborate

what's the quick rundown?

no extra dimensions confirmed

at least not for propagation of gravity

>we place limits on the screening scale for theories with D>4 spacetime dimensions, finding that the screening scale must be greater than ∼20Mpc
what does Mpc mean?

>arxiv.org/abs/1801.08160
gravity wave energy didn't leak into higher dimensions

>gravity wave energy didn't leak into higher dimensions
Why would it?

>what does Mpc mean?
megaparsecs?
en.wikipedia.org/wiki/Parsec

1 pc = 3.26156 ly
20Mpc = 65231200 ly

about 65 million ly

sciencenews.org/article/gravity-doesnt-leak-large-hidden-dimensions
> “We’re not in any way ruling out string theory,” Spergel says.

ask the string theorists. that's sorta the point.

>Sperg

Is this a good thing or a bad thing?

Is MAHNZ ZAVIZI ZAVIZI a bad thing?

String theory is not dead. (And probably won't die until Ed Witten et al have all gotten stakes through their hearts.)
But a few of the possibilities seem to be ruled out.

guys listen just listen what if the universe is made out of

So how does this kill string theory?

lmfao string theory gets it's first ever experimental test and it fails completely. Remind me why we believe in this crock of shit?

Maybe it only applies to 1D string theory?
And why not go with straight 3D particles?

Maybe string theory is bullshit?

Is it Motl, the /pol/tard?

>sciencenews.org/article/gravity-doesnt-leak-large-hidden-dimensions

>A variety of theories predict extra dimensions of spacetime into which gravity could leak, but the new result applies only to large extra dimensions, Spergel says.

Does not rule out String theory at all, retard

Motl doesn't shitpost on kyrghyz regional yak-milking league forums. Apart from his blog and the occasional mania on quora, he trolls the climate alarmists and anti-stringists on their blogs.
Long live string theory!

ITT: OMG YOU GUYZ string theory is dead, but fuck you if you expect me to know what string theory even is lmao

my uncle showed me how to patch a leaky water heater once, is this basically what the physicalists did to stop the gravities from leaking

>we place limits on the screening scale for theories with D>4 spacetime dimensions

Stupid question, but how can our 4D spacetime be curved (by massy objects) if it doesn't lie in a 5D coordinate system?

E.g. a piece of paper can be flat, the it's possible that it really exists in a universe with only 2 spacial dimensions. But if you say it's curved, there need to be a 3rd spacial dimension into which it can curve.

What am I not understanding?

It only affects metrics, space itself doesn't exist.

He posts on /r9k/.

elaborate

read the fucking paper maybe?

>HoW cAn OUr 4D sPacEtImE bE cUrVed (by MAsSy ObJeCtS) iF iT DoeSn'T LiE iN A 5D cOORdInAtE SyStEm?

>reddit spacing
>retarded question

You guys are fucking retarded.

en.wikipedia.org/wiki/Five-dimensional_space

explain pls. this is too good

something can be curved without having to be embedded into a higher dimensional space, you mong

Motl is the single most slavic-looking person I've seen.

How does a brainlet like myself goes about asking for an explanation of why in layman terms?

So you are telling me there are huge mountains and deep valleys inside this meadow? Then why do I need the same amount of time and energy to walk a straight line of 100m on this meadow, no matter where, no matter in which direction?

>arxiv
Disregarded.

Absolutely...but first define what you consider "huge" and "deep".

youtu.be/eN24Sv0qS1w

I don't know and I can't answer that question, but that's how it is because science says so!

"huge" -> curvature of at least -0.2 in both dimensions of the meadow
"deep" -> curvature of at least 0.2 in both dimensions of the meadow

Alright, thought about it. What I'm saying here is that if there is an additional dimension, you should be able to notice a curvature of a lower dimensional object in at least one of realities additional dimensions.

But other anons before just claimed that there can be curvature in n-dimensional objects even though there is no (n+1)-th dimension. But I have another example for that. See pic related. Think of it as a piece of paper that is glued to the table. The paper is a 2D object and because it is glued to the table, it also has no way of leaving a 2D space. The paper basically exists in a 2D world. However, us humans have 3 dimensions available and as we look at it, we can say that the paper has a curvature of 0 at any point. If it had any curvature != 0, we would see it in the 3rd dimension, as demonstrated by the meadow example. Now try to give the paper a curvature without requiring it to leave its 2D-only-world, e.g. without somehow removing the glue and pulling it from the table. Pro tip: you can't.

Not saying I'm right and you are wrong, but what is inaccurate about my examples. I just want to understand.

It's a meme. He doesn't visit Veeky Forums.

string dead is theory....
MAHNZ

Do you seriously expect me ro read a 7 page paper just so you can shitpost at level with me?

Because it gave "Science Fans" something else to masterbate to.

behold
desuarchive.org/r9k/thread/18929562/#18929722

The author of this paper is not only American, which makes the quality of his conclusions inherently dubious (Amerilard physicists are some of the worst), but he's also a graduate student

this is the content of Gauss's Theorema Egregium in part. You can determine the curvature of your space without ever leaving your space. This means you never have to refer to your space from some external flat space.

For instance, another space that is difficult to grasp is the surface of a klein bottle with no curvature anywhere.

you need to study modern differential geometry (keyword: manifold)

thanks. But can you explain what is wrong with my experiments? How to bring curvature in a paper without having it to partly move in the 3rd spatial dimension?

>How to bring curvature in a paper without having it to partly move in the 3rd spatial dimension?
You can't: the paper is part of 3D space, so any sort of transformation on it takes place within this larger space.
However, I can mathematically define curved surfaces without reference to any higher dimensional space that they live in, using differential geometry.
Except in string theory gravity is quantised and the extra dimensions are very small and compact, meaning gravitational waves moving through the extra dimensions have to have exceedingly high momentum: the extra dimensions essentially become frozen out. All they've ruled out are large extra dimensions, but we knew that already.

Mathematicians define curvature as either "intrinsic" or "extrinsic".

A curled sheet of paper remains "flat" insofar at 2-dimensional beings living on the paper can tell. No measurement they can make will tell them they've been curved into a 3rd dimension.
On the other hand, if you try to make the paper conform to a section of a globe, you can't do it. The sheet must either be torn or overlapped to make it fit. That's why all 2D maps of Earth necessarily distort the world in one way or another.
Our world looks "flat" to us as seen from eye-level, but surveyors quickly find that flat (or Euclidian) geometry doesn't work. The interior angles don't add to 180 degrees. It's unnoticeable when the triangles are small, but the discrepancy gets worse and worse as you measure larger areas. That's "intrinsic" curvature.

Intrinsic curvature is a property of the surface itself. Nothing to do with possible "higher" dimensions it might be "embedded" in.

As several others have pointed out, look up "manifolds" for further details.
For a good, non-technical explanation of non-Euclidian geometries (and a very amusing one) I recommend "Flatterland" by Ian Stewart.

ahahahahahaah
holy fuck this is awesome.

"Mr. Supreme Gentleman, I present you the Supreme Intellectual"

It's been dead for years

gravity is dead

When you see quotation marks around an imprecise word like this, this early on, you know you're in for some good shit

please let it die completely

>that Motl mention out of no where

hahahahahaha this is great

You missed the bit where lumo hates Nietzsche and insults the intellect of Erdös. If it was really him, he would mention Dirac without a doubt.

Then what do you propose instead of String/M-theory, and why?

Curvature is an intrinsic property of the space and it therefore doesn't rely on being embedded in some larger 'ambient' space.