Is the Multiverse Hypothesis Losing Steam in Scientific Circles?

[genphis]

After watching a program featuring stephen hawkings, which discussed the beginning of the universe and the big bang. I am troubled by the concept of accepting that there was nothing before the big bang. if indeed it was spurned from a singularity which is infinitely dense with energy/matter where did the energy/matter condense from. are we trying to solve a problem which requires us to think bigger as in the suggestion that our universe is but one bubble amongst many.

 

[Whovian]

This comes from misinterpreting the BBT. Will go into more depth in a moment, when I'm on a better device.

 

[genphis]

ok i appreciate the info

 

[Whovian]

if indeed it was spurned from a singularity which is infinitely dense

It does, but not in the popular sense. The Big Bang tends to refer to the earliest moments of the Universe. I'll use an analogy someone else on the PF came up with, though I can't remember who so I can't give them credit.

Imagine an unbounded fog. Imagine every particle is moving away from each other, but from each one's point of view, none are moving. (Made possible by the concept of expanding space.) It's obviously always been spatially infinite (unless, possibly, the time I'm about to refer to,) but there was a time where all the particles in any finite area were in the same point. This may or may not mean that all particles were at the same point at that moment.

with energy/matter where did the energy/matter condense from.

At least one answer is that trying to define time "before" the BB makes no sense, therefore, there's no reason to ask since there wasn't any time beforehand for it to come from.

are we trying to solve a problem which requires us to think bigger as in the suggestion that our universe is but one bubble amongst many.

We have no reason to think that our Universe is one of many, though that is possible.

 

[genphis]

Thanks, i am also talking about the substance that made our universe, since energy cannot be destroyed, How did it become trapped inside the the singularity.

 

[Whovian]

Thanks, i am also talking about the substance that made our universe, since energy cannot be destroyed, How did it become trapped inside the the singularity.

Again,

a) We're not certain that having a singularity is actually valid
b) Defining time before the BB isn't necessarily valid, so it didn't become trapped in the singularity in the first place
c) There might not have even been a point in time in which there was a singularity, since it's unclear whether or not defining the moment of the BB is valid.

 

[genphis]

i find it odd when we discuss whether it is valid because a lot rests on the process. are we saying nothing existed relevant to our universe, or in the entire idea of existence and what it means. because the bb must of obtained its energy potential from some sort of potential difference in order to create a reaction. and if so where and what is this energy stored in, if not our universe. where is our universe situated. Also with the knowledge of the fractal nature of our universe. is it not conceivable that the answer is within existing processes. sorry for the ramble i understand time is relevant but i would expect us still to perceive time before our existence the same way we look back into our history and still retain a sense of time...

 

[Mark M]

Thanks, i am also talking about the substance that made our universe, since energy cannot be destroyed, How did it become trapped inside the the singularity.

Firstly, you need to understand what a singularity is. It isn't a point in space that is infinitely dense, it's when space itself becomes infinitely curved. This would occur everywhere, energy wasn't 'confined' anywhere. An example of a singularity is the center of mass of an object in the Schwarzschild metric. You can easily see that for r = 0, the metric blows up to infinity.

So, the big bang singularity is the point at which general relativity predicts that the metric becomes nonsensical. This is purely a relic of the fact that GR cannot handle certain situations, including the center of a black hole.

The singularity is just a mathematical object in GR that will not exist in quantum gravity.

 

[Drakkith]

i find it odd when we discuss whether it is valid because a lot rests on the process. are we saying nothing existed relevant to our universe, or in the entire idea of existence and what it means. because the bb must of obtained its energy potential from some sort of potential difference in order to create a reaction. and if so where and what is this energy stored in, if not our universe. where is our universe situated. Also with the knowledge of the fractal nature of our universe. is it not conceivable that the answer is within existing processes. sorry for the ramble i understand time is relevant but i would expect us still to perceive time before our existence the same way we look back into our history and still retain a sense of time...

Most of this is beyond current science and is just speculation. We can make theories but they have to be based on things that are observable. It makes sense that something must exist prior to the universe as it is now, but the universe continues to prove that our idea of what makes sense is, well, nonsense. We simply don't know what happened before a certain point in time we consider to be the earliest moments of the universe.

 

[jackmell]

I am troubled by the concept of accepting that there was nothing before the big bang.

There is in my opinion absolutely nothing wrong with nothing if that nothing is qualitatively different from something and if it is separated from something by a critical point such as the Big Bang singularity. But you have to better understand one effect of a singularity: qualitative change. Think of water trajecting through the critical point of freezing and turning to ice. Some properties of the ice are qualitatively different from the water. For example, you can't swim in a block of ice. The freezing point can in some ways be considered a singualrity and trajecting through the singularity changes (some) of the rules and attempting to use water rules like "swimming" across the singularity and applying it to ice simply does not work. In the same way (perhaps), using our rules we observe in our Universe such as "something" and attempting to apply that (or the absence of something) across the singularity of the Big Bang may simply not be applicapable. The rules (likely) changed when going through the singularity. Some idea or concept qualitatively different from "something" or the absence of something, may be needed.

 

[genphis]

thanks for the input guys. i understand the the ice metaphor sums it up nicely thanks

 

[Naty1]

We have no reason to think that our Universe is one of many, though that is possible.

We have no reason to think that our universe is the only universe.

 

[marcus]

...
We have no reason to think that our Universe is one of many, though that is possible.

I agree, in other words from a scientific viewpoint it is a waste of time to bother contemplating an unnecessary complication. We have enough to do trying to understand our own big bang: the world we see and live in.

I believe "multiverse" thinking has been in decline at least since 2009 and probably earlier. It has been dropped for the most part from the major conferences like MG13 and GR19 where, if the relevant scientific community thought it was interesting, one would have expected it to appear.

Even though it was a string theorist (Susskind) who was most influential in stirring up the "Anthropic String Landscape" multiverse fad, that stuff has been excluded from the String annual conferences since 2007 or so.

There are people who still try to drag multiversery in on the coat tails of inflation, but I think it's gradually being realized this isn't necessary. Although it used to be thought so by some, I don;t believe inflation is made more understandable by having lots of other inflations which don't turn out right.

We hardly need to show evidence that there are NOT a whole bunch other universes (whatever that would mean.) That is a LITERARY type fantasy people can believe if they want. It's not a scientific line of investigation since it is increasingly seen to lack both theoretical necessity and positive supporting evidence. The main proponents have gray hair and the receptive audience now seems mostly non-scientist folks.

 

[skydivephil]

I agree, in other words from a scientific viewpoint it is a waste of time to bother contemplating an unnecessary complication. We have enough to do trying to understand our own big bang: the world we see and live in.

I believe "multiverse" thinking has been in decline at least since 2009 and probably earlier. It has been dropped for the most part from the major conferences like MG13 and GR19 where, if the relevant scientific community thought it was interesting, one would have expected it to appear.

Even though it was a string theorist (Susskind) who was most influential in stirring up the "Anthropic String Landscape" multiverse fad, that stuff has been excluded from the String annual conferences since 2007 or so.

There are people who still try to drag multiversery in on the coat tails of inflation, but I think it's gradually being realized this isn't necessary. Although it used to be thought so by some, I don;t believe inflation is made more understandable by having lots of other inflations which don't turn out right.

We hardly need to show evidence that there are NOT a whole bunch other universes (whatever that would mean.) That is a LITERARY type fantasy people can believe if they want. It's not a scientific line of investigation since it is increasingly seen to lack both theoretical necessity and positive supporting evidence. The main proponents have gray hair and the receptive audience now seems mostly non-scientist folks.

Ive been trying to track this decline but I am not getting the same results as you. Can conference topics can be influenced by the conference organisers? The PI conference last year on the early universe seemd to have many mutliverse talks. But I suspect Turok was keen to have sort of friendly show down between eternal inflation and cyclic models. Not much LQC stuff there which was v dissapointing.

I did an Arxiv search between 2003 and 2007 and between 2007 and 2011 ( I didnt want to inlcude 2012 as its not done yet) for related topics. This is the results I got for how many papers were published:

2003-2007
multiverse 56
eternal inflation 73
string theory landscape 25

2007-2011
eternal inflation 107
multiverse 128
string theory landscape 22

Now I undersdtand that arxiv is imperfect as a measure here because obviously its a lot easier to get it on the arxiv than in a journal. But I am not sure how to search high impact journals only. Maybe the period I selected skewed the result. But id be interested to see any better methods that get results consitent with a decline in interest in the multiverse