Is our universe the only universe?

Via:  TᵢG  •  3 months ago  •  34 comments

Is our universe the only universe?
So we find ourselves in a universe with the particular amount of dark energy we've measured simply because our universe has conditions hospitable to our form of life.

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Critical Thinkers

S E E D E D   C O N T E N T


A few months ago the Nobel Prize in physics was awarded to two teams of astronomers for a discovery that has been hailed as one of the most important astronomical observations ever. And today, after briefly describing what they found, I'm going to tell you about a highly controversial framework for explaining their discovery, namely the possibility that way beyond the Earth, the Milky Way and other distant galaxies, we may find that our universe is not the only universe, but is instead part of a vast complex of universes that we call the multiverse.

00:50

Now the idea of a multiverse is a strange one. I mean, most of us were raised to believe that the word "universe" means everything. And I say most of us with forethought, as my four-year-old daughter has heard me speak of these ideas since she was born. And last year I was holding her and I said, "Sophia, I love you more than anything in the universe." And she turned to me and said, "Daddy, universe or multiverse?" (Laughter)

01:18

But barring such an anomalous upbringing, it is strange to imagine other realms separate from ours, most with fundamentally different features, that would rightly be called universes of their own. And yet, speculative though the idea surely is, I aim to convince you that there's reason for taking it seriously, as it just might be right. I'm going to tell the story of the multiverse in three parts. In part one, I'm going to describe those Nobel Prize-winning results and to highlight a profound mystery which those results revealed. In part two, I'll offer a solution to that mystery. It's based on an approach called string theory, and that's where the idea of the multiverse will come into the story. Finally, in part three, I'm going to describe a cosmological theory called inflation, which will pull all the pieces of the story together.

02:10

Okay, part one starts back in 1929 when the great astronomer Edwin Hubble realized that the distant galaxies were all rushing away from us, establishing that space itself is stretching, it's expanding. Now this was revolutionary. The prevailing wisdom was that on the largest of scales the universe was static. But even so, there was one thing that everyone was certain of: The expansion must be slowing down. That, much as the gravitational pull of the Earth slows the ascent of an apple tossed upward, the gravitational pull of each galaxy on every other must be slowing the expansion of space.

02:55

Now let's fast-forward to the 1990s when those two teams of astronomers I mentioned at the outset were inspired by this reasoning to measure the rate at which the expansion has been slowing. And they did this by painstaking observations of numerous distant galaxies, allowing them to chart how the expansion rate has changed over time. Here's the surprise: They found that the expansion is not slowing down. Instead they found that it's speeding up, going faster and faster. That's like tossing an apple upward and it goes up faster and faster. Now if you saw an apple do that, you'd want to know why. What's pushing on it?

03:39

Similarly, the astronomers' results are surely well-deserving of the Nobel Prize, but they raised an analogous question. What force is driving all galaxies to rush away from every other at an ever-quickening speed? Well the most promising answer comes from an old idea of Einstein's. You see, we are all used to gravity being a force that does one thing, pulls objects together. But in Einstein's theory of gravity, his general theory of relativity, gravity can also push things apart.

04:15

How? Well according to Einstein's math, if space is uniformly filled with an invisible energy, sort of like a uniform, invisible mist, then the gravity generated by that mist would be repulsive, repulsive gravity, which is just what we need to explain the observations. Because the repulsive gravity of an invisible energy in space -- we now call it dark energy, but I've made it smokey white here so you can see it -- its repulsive gravity would cause each galaxy to push against every other, driving expansion to speed up, not slow down. And this explanation represents great progress.

04:56

But I promised you a mystery here in part one. Here it is. When the astronomers worked out how much of this dark energy must be infusing space to account for the cosmic speed up, look at what they found. This number is small. Expressed in the relevant unit, it is spectacularly small. And the mystery is to explain this peculiar number. We want this number to emerge from the laws of physics, but so far no one has found a way to do that.

05:37

Now you might wonder, should you care? Maybe explaining this number is just a technical issue, a technical detail of interest to experts, but of no relevance to anybody else. Well it surely is a technical detail, but some details really matter. Some details provide windows into uncharted realms of reality, and this peculiar number may be doing just that, as the only approach that's so far made headway to explain it invokes the possibility of other universes -- an idea that naturally emerges from string theory, which takes me to part two: string theory.

06:15

So hold the mystery of the dark energy in the back of your mind as I now go on to tell you three key things about string theory. First off, what is it? Well it's an approach to realize Einstein's dream of a unified theory of physics, a single overarching framework that would be able to describe all the forces at work in the universe. And the central idea of string theory is quite straightforward. It says that if you examine any piece of matter ever more finely, at first you'll find molecules and then you'll find atoms and subatomic particles. But the theory says that if you could probe smaller, much smaller than we can with existing technology, you'd find something else inside these particles -- a little tiny vibrating filament of energy, a little tiny vibrating string. And just like the strings on a violin, they can vibrate in different patterns producing different musical notes. These little fundamental strings, when they vibrate in different patterns, they produce different kinds of particles -- so electrons, quarks, neutrinos, photons, all other particles would be united into a single framework, as they would all arise from vibrating strings. It's a compelling picture, a kind of cosmic symphony, where all the richness that we see in the world around us emerges from the music that these little, tiny strings can play.

07:42

But there's a cost to this elegant unification, because years of research have shown that the math of string theory doesn't quite work. It has internal inconsistencies, unless we allow for something wholly unfamiliar -- extra dimensions of space. That is, we all know about the usual three dimensions of space. And you can think about those as height, width and depth. But string theory says that, on fantastically small scales, there are additional dimensions crumpled to a tiny size so small that we have not detected them. But even though the dimensions are hidden, they would have an impact on things that we can observe because the shape of the extra dimensions constrains how the strings can vibrate. And in string theory, vibration determines everything. So particle masses, the strengths of forces, and most importantly, the amount of dark energy would be determined by the shape of the extra dimensions. So if we knew the shape of the extra dimensions, we should be able to calculate these features, calculate the amount of dark energy.

08:52

The challenge is we don't know the shape of the extra dimensions. All we have is a list of candidate shapes allowed by the math. Now when these ideas were first developed, there were only about five different candidate shapes, so you can imagine analyzing them one-by-one to determine if any yield the physical features we observe. But over time the list grew as researchers found other candidate shapes. From five, the number grew into the hundreds and then the thousands -- A large, but still manageable, collection to analyze, since after all, graduate students need something to do. But then the list continued to grow into the millions and the billions, until today. The list of candidate shapes has soared to about 10 to the 500.

09:45

So, what to do? Well some researchers lost heart, concluding that was so many candidate shapes for the extra dimensions, each giving rise to different physical features, string theory would never make definitive, testable predictions. But others turned this issue on its head, taking us to the possibility of a multiverse. Here's the idea. Maybe each of these shapes is on an equal footing with every other. Each is as real as every other, in the sense that there are many universes, each with a different shape, for the extra dimensions. And this radical proposal has a profound impact on this mystery: the amount of dark energy revealed by the Nobel Prize-winning results.

10:29

Because you see, if there are other universes, and if those universes each have, say, a different shape for the extra dimensions, then the physical features of each universe will be different, and in particular, the amount of dark energy in each universe will be different. Which means that the mystery of explaining the amount of dark energy we've now measured would take on a wholly different character. In this context, the laws of physics can't explain one number for the dark energy because there isn't just one number, there are many numbers. Which means we have been asking the wrong question. It's that the right question to ask is, why do we humans find ourselves in a universe with a particular amount of dark energy we've measured instead of any of the other possibilities that are out there?

11:23

And that's a question on which we can make headway. Because those universes that have much more dark energy than ours, whenever matter tries to clump into galaxies, the repulsive push of the dark energy is so strong that it blows the clump apart and galaxies don't form. And in those universes that have much less dark energy, well they collapse back on themselves so quickly that, again, galaxies don't form. And without galaxies, there are no stars, no planets and no chance for our form of life to exist in those other universes.

11:57

So we find ourselves in a universe with the particular amount of dark energy we've measured simply because our universe has conditions hospitable to our form of life. And that would be that. Mystery solved, multiverse found. Now some find this explanation unsatisfying. We're used to physics giving us definitive explanations for the features we observe. But the point is, if the feature you're observing can and does take on a wide variety of different values across the wider landscape of reality, then thinking one explanation for a particular value is simply misguided.

12:44

An early example comes from the great astronomer Johannes Kepler who was obsessed with understanding a different number -- why the Sun is 93 million miles away from the Earth. And he worked for decades trying to explain this number, but he never succeeded, and we know why. Kepler was asking the wrong question.

13:07

We now know that there are many planets at a wide variety of different distances from their host stars. So hoping that the laws of physics will explain one particular number, 93 million miles, well that is simply wrongheaded. Instead the right question to ask is, why do we humans find ourselves on a planet at this particular distance, instead of any of the other possibilities? And again, that's a question we can answer. Those planets which are much closer to a star like the Sun would be so hot that our form of life wouldn't exist. And those planets that are much farther away from the star, well they're so cold that, again, our form of life would not take hold. So we find ourselves on a planet at this particular distance simply because it yields conditions vital to our form of life. And when it comes to planets and their distances, this clearly is the right kind of reasoning. The point is, when it comes to universes and the dark energy that they contain, it may also be the right kind of reasoning.

14:14

One key difference, of course, is we know that there are other planets out there, but so far I've only speculated on the possibility that there might be other universes. So to pull it all together, we need a mechanism that can actually generate other universes. And that takes me to my final part, part three. Because such a mechanism has been found by cosmologists trying to understand the Big Bang. You see, when we speak of the Big Bang, we often have an image of a kind of cosmic explosion that created our universe and set space rushing outward.

14:51

But there's a little secret. The Big Bang leaves out something pretty important, the Bang. It tells us how the universe evolved after the Bang, but gives us no insight into what would have powered the Bang itself. And this gap was finally filled by an enhanced version of the Big Bang theory. It's called inflationary cosmology, which identified a particular kind of fuel that would naturally generate an outward rush of space. The fuel is based on something called a quantum field, but the only detail that matters for us is that this fuel proves to be so efficient that it's virtually impossible to use it all up, which means in the inflationary theory, the Big Bang giving rise to our universe is likely not a one-time event. Instead the fuel not only generated our Big Bang, but it would also generate countless other Big Bangs, each giving rise to its own separate universe with our universe becoming but one bubble in a grand cosmic bubble bath of universes.

16:00

And now, when we meld this with string theory, here's the picture we're led to. Each of these universes has extra dimensions. The extra dimensions take on a wide variety of different shapes. The different shapes yield different physical features. And we find ourselves in one universe instead of another simply because it's only in our universe that the physical features, like the amount of dark energy, are right for our form of life to take hold. And this is the compelling but highly controversial picture of the wider cosmos that cutting-edge observation and theory have now led us to seriously consider.

16:36

One big remaining question, of course, is, could we ever confirm the existence of other universes? Well let me describe one way that might one day happen. The inflationary theory already has strong observational support. Because the theory predicts that the Big Bang would have been so intense that as space rapidly expanded, tiny quantum jitters from the micro world would have been stretched out to the macro world, yielding a distinctive fingerprint, a pattern of slightly hotter spots and slightly colder spots, across space, which powerful telescopes have now observed. Going further, if there are other universes, the theory predicts that every so often those universes can collide. And if our universe got hit by another, that collision would generate an additional subtle pattern of temperature variations across space that we might one day be able to detect. And so exotic as this picture is, it may one day be grounded in observations, establishing the existence of other universes.

17:46

I'll conclude with a striking implication of all these ideas for the very far future. You see, we learned that our universe is not static, that space is expanding, that that expansion is speeding up and that there might be other universes all by carefully examining faint pinpoints of starlight coming to us from distant galaxies. But because the expansion is speeding up, in the very far future, those galaxies will rush away so far and so fast that we won't be able to see them -- not because of technological limitations, but because of the laws of physics. The light those galaxies emit, even traveling at the fastest speed, the speed of light, will not be able to overcome the ever-widening gulf between us. So astronomers in the far future looking out into deep space will see nothing but an endless stretch of static, inky, black stillness. And they will conclude that the universe is static and unchanging and populated by a single central oasis of matter that they inhabit -- a picture of the cosmos that we definitively know to be wrong.

19:02

Now maybe those future astronomers will have records handed down from an earlier era, like ours, attesting to an expanding cosmos teeming with galaxies. But would those future astronomers believe such ancient knowledge? Or would they believe in the black, static empty universe that their own state-of-the-art observations reveal? I suspect the latter. Which means that we are living through a remarkably privileged era when certain deep truths about the cosmos are still within reach of the human spirit of exploration. It appears that it may not always be that way. Because today's astronomers, by turning powerful telescopes to the sky, have captured a handful of starkly informative photons -- a kind of cosmic telegram billions of years in transit. and the message echoing across the ages is clear. Sometimes nature guards her secrets with the unbreakable grip of physical law. Sometimes the true nature of reality beckons from just beyond the horizon.

20:16

Thank you very much.

20:18

(Applause)

20:22

Chris Anderson: Brian, thank you. The range of ideas you've just spoken about are dizzying, exhilarating, incredible. How do you think of where cosmology is now, in a sort of historical side? Are we in the middle of something unusual historically in your opinion?

20:38

BG: Well it's hard to say. When we learn that astronomers of the far future may not have enough information to figure things out, the natural question is, maybe we're already in that position and certain deep, critical features of the universe already have escaped our ability to understand because of how cosmology evolves. So from that perspective, maybe we will always be asking questions and never be able to fully answer them.

21:03

On the other hand, we now can understand how old the universe is. We can understand how to understand the data from the microwave background radiation that was set down 13.72 billion years ago -- and yet, we can do calculations today to predict how it will look and it matches. Holy cow! That's just amazing. So on the one hand, it's just incredible where we've gotten, but who knows what sort of blocks we may find in the future.

21:28

CA: You're going to be around for the next few days. Maybe some of these conversations can continue. Thank you. Thank you, Brian. (BG: My pleasure.)

21:35

(Applause)

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TᵢG
1  seeder  TᵢG    3 months ago

String theory (in spite of its name) is still an hypothesis given there is no method of falsification.   It is largely a sophisticated exploration of theoretical physics in terms of the mathematics of known science.   It is based on and compatible with scientific findings and theories (e.g. Einstein's relativity, Inflation theory, quantum dynamics) and is currently one of the leading candidates for a theory of everything - a theory which unifies the large world described by Relativity with the quantum world.

This seed is a spectacular presentation of complex theoretical science in layman terms.

 
 
MrFrost
2  MrFrost    3 months ago

Unlikely that we are the one and only universe. Black holes suck up, (for lack of a better term), a LOT of stuff... Where does it go? We have found many black holes, but not once instance of, "the ass end of a black hole". My guess? They dump into another universe. Perhaps that's how OUR universe was started? 

 
 
TᵢG
2.1  seeder  TᵢG  replied to  MrFrost @2    3 months ago

There are quite a few theoretical physicists who seriously consider that very hypothesis.

That does have a certain elegance to it.   In a sense eternity is a perpetual motion machine.   Universes are spawned, undergo change, spawn new universes and die.

All speculation of course but plenty of science to back it up as plausible (vs. wishful thinking).

 
 
MrFrost
2.1.1  MrFrost  replied to  TᵢG @2.1    3 months ago

As to creation of the universe... It's true that our universe is expanding, everything is moving away from a fairly central point that we cannot see, (it's difficult to explain, but I am sure you know what I mean). We also know that the expansion is slowing down. I don't think that it's beyond reason to think that when the expansion stops, and starts to fall back into itself via gravity that the universe could collapse into one single point, and explode, thereby starting all over again. 

Again, just a thought. 

All speculation of course but plenty of science to back it up as plausible (vs. wishful thinking).

That's one of the reasons I love science. 

 
 
TᵢG
2.1.2  seeder  TᵢG  replied to  MrFrost @2.1.1    3 months ago
We also know that the expansion is slowing down.

Best I can tell expansion is speeding up.   The cause is dark energy - but nobody knows what dark energy is.

I don't think that it's beyond reason to think that when the expansion stops, and starts to fall back into itself via gravity that the universe could collapse into one single point, and explode, thereby starting all over again. 

There are hypotheses, however, that the accelerated expansion is a temporary condition and that we will start seeing a reversal of dark energy effects - a contraction - returning back to the old hypothesis of the 'big crunch'.   This is all up in the air, but cosmologists currently tend to favor the cold death ('the Big Freeze') of our universe resulting from endless expansion.   (Nobody likes that scenario of course, but it seems most likely based on current evidence.)

 
 
TᵢG
2.1.3  seeder  TᵢG  replied to  MrFrost @2.1.1    3 months ago
We also know that the expansion is slowing down.

Here Neil Turok offers his views and this includes his hypothesis of the universe contracting.

 
 
Dignitatem Societatis
2.1.4  Dignitatem Societatis  replied to  TᵢG @2.1.2    3 months ago
 The cause is dark energy - but nobody knows what dark energy is.

I was thinking about dark energy just the other day, and something occurred to me that I hadn't thought of before. It's pretty much the missing opposite of gravity's attractive force.

What I mean is that the other forces are both attractive and repulsive depending on polarities. Gravity has always seemed like the odd man out, seemingly having only a singular attractive force between everything with mass.

What if dark energy is just the repulsive side of gravity? What if it's the same force? In the same way that magnetism attracts opposite polarities and repels like polarities, what if dark energy is just a previously unknown feature of the gravitational force that repels mass instead of attracting it, depending on an as yet unknown property of mass acting like polarity does with the other forces?

The fact that the universe is expanding and even accelerating could result from mass in the universe being ordered in such a way as to make the repulsive side of the force slightly more present than the attractive side. It would be the opposite of how the attractive side of the magnetic force always wins out, like when you toss a bunch of magnets into a bowl and they flip around and jostle themselves until they are all locked together (attraction wins out over repulsion even though the repelling side of magnetism is still there). Maybe the universe is still in the process of the repelling side of gravity winning out over the attractive side. The opposite of magnets tossed into a bowl.

Hasn't it always seemed strange that gravity only did one thing?

I don't know. It was just a thought.

 
 
TᵢG
2.1.5  seeder  TᵢG  replied to  Dignitatem Societatis @2.1.4    3 months ago

A number of theoretical physicists share your view.    The thing is, if dark energy is an anti-gravity this could affect Relativity the way Relativity affected Newtonian Gravity.   We could be at the beginning of a major step forward.

I guess we wait.   We can have fun speculating for a while because I suspect dark energy will elude us for quite some time.  

 
 
Gordy327
2.2  Gordy327  replied to  MrFrost @2    3 months ago
Unlikely that we are the one and only universe.

Pondering the existence of other universes and dimensions is a fascinating concept, especially when it becomes infinite universes. 

Black holes suck up, (for lack of a better term), a LOT of stuff... Where does it go?

As far as we know (or speculate), everything gets gravitationally compressed into a singularity. 

We have found many black holes, but not once instance of, "the ass end of a black hole". My guess? They dump into another universe.

That would imply the process is a two-way street: things from the other universe gets dumped into ours by the same process. Kind of like a cosmic digestive system: things gets sucked in (eaten), compressed (digested), and expelled (elimination).

Perhaps that's how OUR universe was started? 

You mean this universe resulted from a cosmic explosive diarrhea (possibly after constipation)? chuckle

 
 
MrFrost
2.2.1  MrFrost  replied to  Gordy327 @2.2    3 months ago

Yes! Lol

 
 
Perrie Halpern R.A.
3  Perrie Halpern R.A.    3 months ago

Tig,

There is a kind of unification that you have to address. 

At the end of the video, Brian says that we are living a unique time. One where we can see things that men in the future, will not be able to see. That all that will be left are our writings.. one could say "men with pens", and not only will they not believe us, they will think they are right, since they have better instruments, albeit what they can see, is now out of site. 

Now as he went through the first part, he talked of varying theories, and I am sure that future man will look at these theories as proof we were wrong. You must see where I am going with this. 

I am not trying to derail this discussion. But think about it... it is an interesting proposal that all the ancient men with pens, might have not been wrong about everything. Maybe a spiritual multiverse is more like the B'hai. 

btw.. I won't mind if you delete this. It was just something that popped into my brain. 

and I love Brian, which is brain when you change the a and the i. 

 
 
TᵢG
3.1  seeder  TᵢG  replied to  Perrie Halpern R.A. @3    3 months ago
But think about it... it is an interesting proposal that all the ancient men with pens, might have not been wrong about everything.

In Brian's scenario, we are the ancients.   But this scenario is billions of years in the future.   So much time will have passed that the reality of our environment (as measured by science) will be substantially different.   If recorded history is interrupted and the scientists of the time must rely only upon what they see, they will have no knowledge of any other galaxy.   (Best we can tell.)   We really will know things that they do not know (and will never know).   So, sure, I see your point.  Quite honestly, this part led me to the exact same thought when I first watched the video.

There is a rather substantial difference between future humans and us versus us and our ancients.  Our ancients are but a few thousand years in the past and on Brian's scale, this is actually extremely close in time.  To visualize this, imagine that the billions of years in the future per Brian is a single year.   Given that, our ancients were alive ~30 seconds ago.   That is how close we are to our ancients and how far away the future that Brian describes.   Our environment, from a scientific perspective, is virtually identical to that of our ancients.   Thus what science can see now is pretty much what science could see a few thousand years ago.   Finally, we do have recorded history and have knowledge of the claims and (for the most part) the means to verify same.

The ancient men with pens of course are not wrong about everything - probably correct about most things.   But on the big stuff (e.g. Noah's flood, a single couple as a uniquely created species being the ancestors of all human beings, language produced from a tower project, and myriad other lesser things such as the moon being the light of the night and vegetation prior to sunlight, ....) we have sufficient knowledge now to raise an eyebrow on the veracity of the men behind those pens.

 
 
CB
4  CB    3 months ago

Opening question, the video speaks about galaxies racing away leading behind "inky blackness". . . our own galaxy will still exist around us and provide something to study? Please clarify: Are the galaxies all around our own racing away, on all sides?

Before I continue, it is fascinating to watch man explain and attempt to explain what is going on outside its sphere of power and knowledge.

Does it strike anybody perverse, that we are something we know that has not always existed, which to our limited knowledge is the thinking part of the universe?

 
 
TᵢG
4.1  seeder  TᵢG  replied to  CB @4    3 months ago
Are the galaxies all around our own racing away, on all sides?

Yes.   Imagine all galaxies are on the surface of a balloon that is being inflated.   The galaxies are maintaining their integrity (they are not expanding) but the space between them is expanding (at an accelerated pace).

Before I continue, it is fascinating to watch man explain and attempt to explain what is going on outside its sphere of power and knowledge.

Most of this is very educated speculation.    Dr. Greene can take this down to the lowest level of detail and explain the underlying theories and the empirical results upon which they are based.   But the important thing to note is that science recognizes the multiverse as an hypothesis - not a bona fide theory of science.   

Does it strike anybody perverse, that we are something we know that has not always existed, which to our limited knowledge is the thinking part of the universe?

There is so much that we do not know.  This does not strike me as perverse.   Actually I am quite impressed with how much information science has been able to glean by measuring electromagnetic waves, gravitational waves and the behavior of particles.

 
 
CB
4.1.1  CB  replied to  TᵢG @4.1    3 months ago
we are something we know that has not always existed, which to the limited knowledge of science is the only thinking part of the universe?

The answers we get about the encompassing universe comes from inside the universe on a 'rock', that is my point!

 
 
TᵢG
4.1.2  seeder  TᵢG  replied to  CB @4.1.1    3 months ago

Well if we ever come in contact with an extraterrestrial we would be able to share perspectives.   Until that time, we are all on planet Earth looking out at the cosmos and down into the quantum world.

 
 
CB
4.1.3  CB  replied to  TᵢG @4.1.2    3 months ago

As Carl Sagan stated, and I paraphrase, 'We on on a small planet in a sea of stars, planets, and stuff.' And we, without added information from any ET's have the intellect to think outside our "margins."

 
 
CB
6  CB    3 months ago

He appears to be saying that in each conceptualized multiverse, there could be at least one fined-tuned planet. I am going to ask a leading question which I do not believe to be the case:

Does Dr. Greene seem to say that only one planet in our system is 'fine-tuned'? Or, did he just go with the model of our universe as we know it, in order to make his larger points?

Now for a surreal or sublime question: Where are all these galaxies, and 'multiverses' being shunted off to?

 
 
TᵢG
6.1  seeder  TᵢG  replied to  CB @6    3 months ago
He appears to be saying that in each conceptualized multiverse, there could be at least one fined-tuned planet.

Dr. Greene is saying something very different.   He is saying that of the 10500 possible universes many of them will not be able to support any form of life (or even stars and planets).  The others that can support life might not be life as we would define it and there certainly is the possibility that alternate universes exist that support life exactly as we know it.

Does Dr. Greene seem to say that only one planet in our system is 'fine-tuned'? Or, did he just go with the model of our universe as we know it, in order to make his larger points?

First, he is accepting the language of 'fine-tuning' as it applies to the universe.   Probably to be generous.   He acknowledges that very few changes could make our universe entirely inhospitable to life.   Per Earth he is noting that even in our universe there are very specific conditions that must be present for life as we know it to exist.    He is not claiming that only Earth fits that definition.   Plenty of exoplanets in the Goldilocks zone have been discovered.   But we do not currently know of any planet with life as we know it.

Now for a surreal or sublime question: Where are all these galaxies, and 'multiverses' being shunted off to?

I do not understand your question.

 
 
CB
6.1.1  CB  replied to  TᵢG @6.1    3 months ago
The others that can support life might not be life as we would define it and there certainly is the possibility that alternate universes exist that support life exactly as we know it.

Because of their physical laws being different, or the same as our physical laws.

First, he is accepting the language of 'fine-tuning' as it applies to the universe.   Probably to be generous.

I do not care why he uses the term, I simply am using the words he used and included in the video title. Alternatively, he could have labeled it, "Just right" conditions and it would not bother me. Carbon and water-based lifeforms, we are!

 
 
TᵢG
6.1.2  seeder  TᵢG  replied to  CB @6.1.1    3 months ago
Because of their physical laws being different, or the same as our physical laws.

Different 'laws'.

 
 
CB
6.1.3  CB  replied to  TᵢG @6.1    3 months ago
Now for a surreal or sublime question: Where are all these galaxies, and 'multiverses' being shunted off to?

Where and what are their destinations; endpoints?

 
 
TᵢG
6.1.4  seeder  TᵢG  replied to  CB @6.1.3    3 months ago

Do you mean what is their ultimate fate?    If so I have not read (or heard) anything from theoretical physicists that predict the end state for other universes.   I cannot imagine how the state of the art could possibly opine on that given we are unsure about the end state of our own universe.

 
 
CB
6.1.5  CB  replied to  TᵢG @6.1.4    3 months ago

Well, is it safe to say the other hypothetical universes will meet an 'ultimate fate' before our own?

 
 
TᵢG
6.1.6  seeder  TᵢG  replied to  CB @6.1.5    3 months ago

Why would you think that?   

 
 
CB
6.1.7  CB  replied to  TᵢG @6.1.6    3 months ago

I probably should have used, "may" in place of, "will."

My thinking is there is a 'wall' or as I stated above an, "endpoint" to all this receding away. Of course, it is speculation on my part, too.

 
 
TᵢG
6.1.8  seeder  TᵢG  replied to  CB @6.1.7    3 months ago

All of this is highly speculative.   String theory itself is structured, scientific speculation so any thoughts on the various realities that might be true is really out there.   In short:  nobody could possibly know.

 
 
MrFrost
7  MrFrost    2 months ago

For all we know, our entire universe could be in a drop of water in a vast ocean, on a planet, in an 'infinite' universe that is as well...living in a drop of water, in a vast ocean..... 

 
 
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