January 3, 2025 • 11 mins
In this thought-provoking episode of Cosmos in a Pod, Amitesh delves into one of the most captivating theories in modern physics: the multiverse. Could our universe be just one of countless others? From parallel worlds shaped by quantum mechanics to bubble universes born in the chaos of cosmic inflation, we explore the science, origins, and profound implications of this mind-bending idea.
Key Highlights:
- What Is the Multiverse Theory?
- A framework suggesting the existence of multiple, possibly infinite universes.
- Each universe may have unique physical laws, constants, and realities.
- Types of Multiverses:
- Infinite Universes: Every possible configuration of matter could exist somewhere in an infinite cosmos.
- Bubble Universes: Independent universes formed during cosmic inflation.
- Quantum Multiverse: Parallel realities spawned by quantum events, based on the Many-Worlds Interpretation.
- String Theory Multiverse: Universes arising from different configurations of string theory’s extra dimensions.
- Brane Multiverse: Universes as "branes" floating in a higher-dimensional space.
- Origins of the Idea:
- Rooted in quantum mechanics, string theory, and the inflationary model of the Big Bang.
- Influenced by philosophical musings on the nature of reality.
- Evidence and Challenges:
- Supporting evidence includes the fine-tuning of physical constants and cosmic microwave background anomalies.
- Criticisms focus on the lack of direct observation, testability, and reliance on speculative physics.
- Implications of the Multiverse:
- Could explain why our universe is perfectly tuned for life.
- Raises questions about free will, alternate histories, and the nature of reality.
- Reframes humanity’s place in the cosmos, suggesting we’re part of an incomprehensibly vast ensemble of universes.
- Future Research:
- Cosmic background studies to detect potential interactions between universes.
- Advances in string theory and quantum experiments for indirect evidence.
- Philosophical and theoretical work to refine our understanding of multiverse implications.
Why It Matters:
The multiverse theory pushes the boundaries of science and philosophy, challenging us to rethink the nature of existence. Whether or not we ever confirm its reality, it provides a profound framework for exploring the unknown and grappling with our place in a potentially infinite cosmos.
Unanswered Questions to Ponder:
- Can we ever prove the multiverse exists?
- Do other universes have similar or entirely different laws of physics?
- How does the multiverse impact our understanding of meaning and purpose?
Tune in to explore the fascinating concept of the multiverse and its transformative implications for science, philosophy, and our understanding of reality.
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:00):
ever look up at the night sky and just feel like there's gotta be more out there.
(00:05):
What if our universe is just a tiny piece of something way bigger and, I don't know,
more complicated?
Welcome to Cosmos in a Pod, Space and Astronomy series.
So today we're diving deep into the multiverse.
The idea that maybe there are tons of other universes out there, each with its own laws
of physics and maybe even different versions of us running around.
(00:27):
It's an idea that's been around for a while.
Scientists, philosophers, sci-fi fans, they all love it.
And the thing is, it's not just like a made-up story.
The idea of the multiverse comes from some pretty serious physics.
Yeah, that's what I find so cool about it.
There's actual science behind it.
But before we get too deep into the theories, can you kind of explain what we're talking
about when we say multiverse?
Like paint a picture for our listeners.
(00:48):
So imagine our universe right.
All the galaxies, stars, planets, everything.
Picture that as just one bubble.
And this bubble is floating in this giant cosmic foam.
And each bubble is a separate universe.
Maybe some are similar to ours, but some could be so different we couldn't even imagine them.
Whoa.
So we're not just talking about like a few extra planets or stars.
(01:09):
We're talking entirely different realities.
Yeah.
And maybe like an infinite number of them.
Yeah, that's the thing.
It's a massive concept.
It's kind of hard to wrap your head around.
It is.
It makes you rethink what's real, what's possible.
And like I said, this isn't just imagination.
It comes from some really important physics theories, things like quantum mechanics, cosmic
inflation string theory.
(01:31):
OK, let's start with quantum mechanics.
How does that connect to the multiverse?
So one of the weirdest parts of quantum mechanics is this thing called superposition.
Basically a particle can be in multiple states at the same time until you observe it.
And there's one interpretation of this called the many worlds interpretation.
And it says that every time a quantum measurement is made, every time a particle picks one state
(01:53):
up, the universe splits.
It creates a new branch of reality where the other outcome happens.
So like every decision, every tiny quantum event creates a new universe.
Exactly.
And each of those universes keeps branching out with every other quantum event.
So you end up with this crazy complex multiverse that just keeps growing.
That's wild.
(02:14):
So there's a universe out there where I picked a totally different job or like have
a different family.
It makes you think about all the what ifs.
It does.
And that leads to another cool part of the multiverse, cosmic inflation.
OK, hit me with it.
What's cosmic inflation and how does it fit in?
So the theory of cosmic inflation says that right after the Big Bang, like a fraction
of a second after the universe expanded incredibly fast, like way faster than the speed of light.
(02:38):
And during this crazy expansion, different parts of space time could have expanded and
separated.
They form their own distinct universes, each maybe with different properties.
So it's like the universe had a growth spurt.
And during that spurt, different parts kind of butted off to become their own universes.
Yeah, that's a good way to picture it.
And each of those bubble universes could have totally different physics, you know, like
(02:59):
different gravity or even a different speed of light.
So you could have this crazy variety of cosmic environments.
OK.
And what about string theory?
That's another one I've heard supports the multiverse, but it's super complicated.
Can you break it down?
Yeah, string theory is definitely complex.
So basically it says that the smallest billing blocks of the universe aren't particles,
they're these tiny vibrating strings.
(03:21):
And the way these strings vibrate determines the forces and particles we see.
Now the thing is, string theory says we need more than the three dimensions we experience.
Like extra dimensions.
That sounds like sci-fi.
It does, but the map of string theory needs them.
And here's the connection to the multiverse.
String theory says that different universes could be created by different arrangements
(03:44):
of these extra dimensions.
Think of these extra dimensions curled up in these tiny crazy shapes.
And each shape could be a different universe with its own unique laws of physics.
So each universe is like a different musical note played by a different vibration of the
strings in those extra dimensions.
Yeah, that's a cool way to think about it.
(04:04):
And it shows how string theory could allow for like a huge variety of universes.
OK, so we've talked about some pretty mind blowing theories and they all seem to point
to this idea of a multiverse.
But is there any like actual evidence for it?
Can we ever really prove or disprove that other universes exist?
That's the tricky part about the multiverse.
Actually seeing other universes, that's, you know, beyond what we can do right now.
(04:27):
But it doesn't mean we have no clues at all.
There are some pretty interesting things that might hint at the multiverse.
OK, I'm listening.
What kind of evidence are we talking about?
Well, one thing is cosmic inflation itself.
The predictions from inflation theory, they line up really well with what we see in the
cosmic microwave background radiation.
That's like the afterglow of the Big Bang.
And this agreement between the theory and the observations, it gives us some confidence
(04:51):
in inflation.
And if inflation is right, then multiple universes could totally come from it.
So because inflation seems like a solid theory, it makes the multiverse more likely.
What else is there?
Another piece of the puzzle is this thing called the fine tuning problem.
It's the idea that the fundamental constants of physics, you know, like the strength of
gravity or the mass of an electron, they seem incredibly fine tuned for life to exist.
(05:15):
If these constants were even a little bit different, the universe wouldn't be the same.
So it's like the universe hit the jackpot with all the right settings for stars and planets
and, you know, eventually us.
Exactly.
And the multiverse could explain this fine tuning.
Think about it.
If there are tons of universes with different constants, then statistically, at least one
of them would have the right conditions for life.
(05:36):
And hey, we just happen to be in that one.
I see.
So if we're saying our universe is just super special, we could say it's just one of many
and we happen to be in the one that works for life.
Right.
But, you know, even though this is all interesting, it's not like we have proof of the multiverse.
There are also some problems and criticisms to think about.
All right, let's hear them.
What are the biggest challenges for this theory?
(05:58):
Well, the main one is that we don't have direct evidence.
Like we were saying, we can't actually see other universes, so it's hard to really prove
they're out there.
Yeah, that makes sense.
It's a huge idea and it's going to take some really strong evidence to convince everyone.
For sure.
And that leads to another problem, falsifiability.
For a theory to be scientific, there needs to be a way to test it, a way to maybe prove
(06:23):
it wrong.
But with the multiverse, it's not clear how we could do an experiment to really prove
it one way or another.
So the challenge is to find a way to test the multiverse to make it more than just a
cool idea.
Exactly.
The other point that people bring up is Occam's razor.
It's this idea that the simplest explanation is usually the right one.
(06:43):
And some people say that saying there are infinite universes is way too complicated.
Maybe there's a simpler explanation for what we see.
Okay, so it's a debate about finding the most elegant and simple explanation.
Do we really need infinite universes or is there a simpler answer?
That's the question scientists are trying to figure out.
And then, you know, besides the science stuff, the multiverse also brings up some really
(07:05):
deep philosophical questions.
Oh, yeah, I can imagine.
Thinking about infinite universes, infinite versions of ourselves that has to lead to
some crazy ideas.
Yeah.
Where do we even begin with that?
I think one of the first things we have to ask is what does the multiverse mean for our
place in the cosmos?
Like if our universe is just one of countless others, does that mean our existence is less
significant or does it make it even more special?
(07:29):
That's a question I think a lot of people struggle with.
On one hand, it's humbling to think we're just a tiny part of this huge multiverse.
But on the other hand, it's kind of amazing to imagine how much is out there.
Exactly.
And it also makes us think about free will.
If there are infinite versions of us making every possible choice, does that mean our
(07:49):
choices don't really matter?
Whoa, that's a tough one.
Like if every decision I make creates a new universe where I made a different one, what
does that say about my choices in this universe?
It makes you question everything.
It really does.
And then there's the even bigger question of what is reality.
If we're just a small piece of this massive multiverse, what does that mean for how we
(08:11):
see the universe?
Like what does real even mean anymore?
It's like the multiverse series making us rethink everything we thought we knew about
the universe and ourselves.
It's exciting, but also kind of scary.
Yeah.
So it sounds like the multiverse opens up a ton more questions than it answers.
But even if it's just a theory, it seems worth exploring, right?
Like what kind of research could help us understand this whole multiverse thing better?
(08:31):
You're right.
It's a journey with a lot of potential.
And one promising area is to keep studying the cosmic microwave background radiation.
We talked about how its patterns support cosmic inflation.
But if we look even closer at its tiny variations, we might find more clues.
Some scientists think those variations might actually show signs of collisions or interactions
(08:52):
with other universes, like little fingerprints left over from the very beginning.
Wow, cosmic fingerprints.
That's pretty cool.
Yeah.
It would be amazing to find those, but it's really tough.
You need incredibly precise measurements and some serious data analysis.
But hey, it could lead to huge discoveries.
Another exciting thing is how string theory and its related theories like M theory are
(09:14):
developing.
We touched on this earlier, but string theory naturally leads to the idea of a multiverse,
with different universes coming from different configurations of those extra dimensions.
And if we can find ways to test these theories, it could give us more solid mathematical evidence
for the multiverse.
So we're on the edge of a totally new understanding of reality.
What are the researchers out there?
(09:34):
Well, quantum physics has a ton of potential too.
With advancements in quantum computing and experiments with entanglement, we might be
able to explore the limits of quantum mechanics in ways we never could before.
And some researchers think this could give us indirect evidence for parallel universes.
We might even be able to catch a glimpse of these other realities.
Whoa, quantum computers looking at other universes.
(09:56):
That sounds crazy, but so cool.
It's definitely an exciting idea.
And of course, alongside all the science we need to keep thinking about the philosophical
side of things, philosophers, physicists, cosmologists, they're all working together
to explore the nature of reality, the idea of infinity, what it means to exist in a multiverse.
It's a huge effort bringing together some of the smartest people to tackle some of the
(10:19):
biggest questions we've ever had.
So basically trying to understand the multiverse is pushing the boundaries of what we know
and what we can even imagine.
Absolutely.
And even if we never actually travel to another universe or meet another version of ourselves,
just trying to understand it is giving us incredible insights into the cosmos and our
place in it.
It really shows that the universe, or I guess I should say the multiverse, is full of wonder
(10:43):
and mystery and possibilities.
And even if we don't find all the answers, just asking the questions and exploring is
what makes it so fascinating.
I totally agree.
It shows how curious we are as humans and how much we want to understand the world or
I guess the world's around us.
So to everyone listening, if you're intrigued by this idea of a massive multiverse with
endless possibilities, keep looking up at the stars, keep asking questions, keep exploring.
(11:08):
We're just at the beginning of this journey and who knows what amazing discoveries are
waiting for us.
And don't forget to subscribe to Cosmos in a Pod for more deep dives into the universe
and check out our YouTube channel for some awesome visuals.
Thanks for joining us on this cosmic adventure.
ever look up at the night sky and just feel like there's gotta be more out there.
(00:05):
What if our universe is just a tiny piece of something way bigger and, I don't know,
more complicated?
Welcome to Cosmos in a Pod, Space and Astronomy series.
So today we're diving deep into the multiverse.
The idea that maybe there are tons of other universes out there, each with its own laws
of physics and maybe even different versions of us running around.
(00:27):
It's an idea that's been around for a while.
Scientists, philosophers, sci-fi fans, they all love it.
And the thing is, it's not just like a made-up story.
The idea of the multiverse comes from some pretty serious physics.
Yeah, that's what I find so cool about it.
There's actual science behind it.
But before we get too deep into the theories, can you kind of explain what we're talking
about when we say multiverse?
Like paint a picture for our listeners.
(00:48):
So imagine our universe right.
All the galaxies, stars, planets, everything.
Picture that as just one bubble.
And this bubble is floating in this giant cosmic foam.
And each bubble is a separate universe.
Maybe some are similar to ours, but some could be so different we couldn't even imagine them.
Whoa.
So we're not just talking about like a few extra planets or stars.
(01:09):
We're talking entirely different realities.
Yeah.
And maybe like an infinite number of them.
Yeah, that's the thing.
It's a massive concept.
It's kind of hard to wrap your head around.
It is.
It makes you rethink what's real, what's possible.
And like I said, this isn't just imagination.
It comes from some really important physics theories, things like quantum mechanics, cosmic
inflation string theory.
(01:31):
OK, let's start with quantum mechanics.
How does that connect to the multiverse?
So one of the weirdest parts of quantum mechanics is this thing called superposition.
Basically a particle can be in multiple states at the same time until you observe it.
And there's one interpretation of this called the many worlds interpretation.
And it says that every time a quantum measurement is made, every time a particle picks one state
(01:53):
up, the universe splits.
It creates a new branch of reality where the other outcome happens.
So like every decision, every tiny quantum event creates a new universe.
Exactly.
And each of those universes keeps branching out with every other quantum event.
So you end up with this crazy complex multiverse that just keeps growing.
That's wild.
(02:14):
So there's a universe out there where I picked a totally different job or like have
a different family.
It makes you think about all the what ifs.
It does.
And that leads to another cool part of the multiverse, cosmic inflation.
OK, hit me with it.
What's cosmic inflation and how does it fit in?
So the theory of cosmic inflation says that right after the Big Bang, like a fraction
of a second after the universe expanded incredibly fast, like way faster than the speed of light.
(02:38):
And during this crazy expansion, different parts of space time could have expanded and
separated.
They form their own distinct universes, each maybe with different properties.
So it's like the universe had a growth spurt.
And during that spurt, different parts kind of butted off to become their own universes.
Yeah, that's a good way to picture it.
And each of those bubble universes could have totally different physics, you know, like
(02:59):
different gravity or even a different speed of light.
So you could have this crazy variety of cosmic environments.
OK.
And what about string theory?
That's another one I've heard supports the multiverse, but it's super complicated.
Can you break it down?
Yeah, string theory is definitely complex.
So basically it says that the smallest billing blocks of the universe aren't particles,
they're these tiny vibrating strings.
(03:21):
And the way these strings vibrate determines the forces and particles we see.
Now the thing is, string theory says we need more than the three dimensions we experience.
Like extra dimensions.
That sounds like sci-fi.
It does, but the map of string theory needs them.
And here's the connection to the multiverse.
String theory says that different universes could be created by different arrangements
(03:44):
of these extra dimensions.
Think of these extra dimensions curled up in these tiny crazy shapes.
And each shape could be a different universe with its own unique laws of physics.
So each universe is like a different musical note played by a different vibration of the
strings in those extra dimensions.
Yeah, that's a cool way to think about it.
(04:04):
And it shows how string theory could allow for like a huge variety of universes.
OK, so we've talked about some pretty mind blowing theories and they all seem to point
to this idea of a multiverse.
But is there any like actual evidence for it?
Can we ever really prove or disprove that other universes exist?
That's the tricky part about the multiverse.
Actually seeing other universes, that's, you know, beyond what we can do right now.
(04:27):
But it doesn't mean we have no clues at all.
There are some pretty interesting things that might hint at the multiverse.
OK, I'm listening.
What kind of evidence are we talking about?
Well, one thing is cosmic inflation itself.
The predictions from inflation theory, they line up really well with what we see in the
cosmic microwave background radiation.
That's like the afterglow of the Big Bang.
And this agreement between the theory and the observations, it gives us some confidence
(04:51):
in inflation.
And if inflation is right, then multiple universes could totally come from it.
So because inflation seems like a solid theory, it makes the multiverse more likely.
What else is there?
Another piece of the puzzle is this thing called the fine tuning problem.
It's the idea that the fundamental constants of physics, you know, like the strength of
gravity or the mass of an electron, they seem incredibly fine tuned for life to exist.
(05:15):
If these constants were even a little bit different, the universe wouldn't be the same.
So it's like the universe hit the jackpot with all the right settings for stars and planets
and, you know, eventually us.
Exactly.
And the multiverse could explain this fine tuning.
Think about it.
If there are tons of universes with different constants, then statistically, at least one
of them would have the right conditions for life.
(05:36):
And hey, we just happen to be in that one.
I see.
So if we're saying our universe is just super special, we could say it's just one of many
and we happen to be in the one that works for life.
Right.
But, you know, even though this is all interesting, it's not like we have proof of the multiverse.
There are also some problems and criticisms to think about.
All right, let's hear them.
What are the biggest challenges for this theory?
(05:58):
Well, the main one is that we don't have direct evidence.
Like we were saying, we can't actually see other universes, so it's hard to really prove
they're out there.
Yeah, that makes sense.
It's a huge idea and it's going to take some really strong evidence to convince everyone.
For sure.
And that leads to another problem, falsifiability.
For a theory to be scientific, there needs to be a way to test it, a way to maybe prove
(06:23):
it wrong.
But with the multiverse, it's not clear how we could do an experiment to really prove
it one way or another.
So the challenge is to find a way to test the multiverse to make it more than just a
cool idea.
Exactly.
The other point that people bring up is Occam's razor.
It's this idea that the simplest explanation is usually the right one.
(06:43):
And some people say that saying there are infinite universes is way too complicated.
Maybe there's a simpler explanation for what we see.
Okay, so it's a debate about finding the most elegant and simple explanation.
Do we really need infinite universes or is there a simpler answer?
That's the question scientists are trying to figure out.
And then, you know, besides the science stuff, the multiverse also brings up some really
(07:05):
deep philosophical questions.
Oh, yeah, I can imagine.
Thinking about infinite universes, infinite versions of ourselves that has to lead to
some crazy ideas.
Yeah.
Where do we even begin with that?
I think one of the first things we have to ask is what does the multiverse mean for our
place in the cosmos?
Like if our universe is just one of countless others, does that mean our existence is less
significant or does it make it even more special?
(07:29):
That's a question I think a lot of people struggle with.
On one hand, it's humbling to think we're just a tiny part of this huge multiverse.
But on the other hand, it's kind of amazing to imagine how much is out there.
Exactly.
And it also makes us think about free will.
If there are infinite versions of us making every possible choice, does that mean our
(07:49):
choices don't really matter?
Whoa, that's a tough one.
Like if every decision I make creates a new universe where I made a different one, what
does that say about my choices in this universe?
It makes you question everything.
It really does.
And then there's the even bigger question of what is reality.
If we're just a small piece of this massive multiverse, what does that mean for how we
(08:11):
see the universe?
Like what does real even mean anymore?
It's like the multiverse series making us rethink everything we thought we knew about
the universe and ourselves.
It's exciting, but also kind of scary.
Yeah.
So it sounds like the multiverse opens up a ton more questions than it answers.
But even if it's just a theory, it seems worth exploring, right?
Like what kind of research could help us understand this whole multiverse thing better?
(08:31):
You're right.
It's a journey with a lot of potential.
And one promising area is to keep studying the cosmic microwave background radiation.
We talked about how its patterns support cosmic inflation.
But if we look even closer at its tiny variations, we might find more clues.
Some scientists think those variations might actually show signs of collisions or interactions
(08:52):
with other universes, like little fingerprints left over from the very beginning.
Wow, cosmic fingerprints.
That's pretty cool.
Yeah.
It would be amazing to find those, but it's really tough.
You need incredibly precise measurements and some serious data analysis.
But hey, it could lead to huge discoveries.
Another exciting thing is how string theory and its related theories like M theory are
(09:14):
developing.
We touched on this earlier, but string theory naturally leads to the idea of a multiverse,
with different universes coming from different configurations of those extra dimensions.
And if we can find ways to test these theories, it could give us more solid mathematical evidence
for the multiverse.
So we're on the edge of a totally new understanding of reality.
What are the researchers out there?
(09:34):
Well, quantum physics has a ton of potential too.
With advancements in quantum computing and experiments with entanglement, we might be
able to explore the limits of quantum mechanics in ways we never could before.
And some researchers think this could give us indirect evidence for parallel universes.
We might even be able to catch a glimpse of these other realities.
Whoa, quantum computers looking at other universes.
(09:56):
That sounds crazy, but so cool.
It's definitely an exciting idea.
And of course, alongside all the science we need to keep thinking about the philosophical
side of things, philosophers, physicists, cosmologists, they're all working together
to explore the nature of reality, the idea of infinity, what it means to exist in a multiverse.
It's a huge effort bringing together some of the smartest people to tackle some of the
(10:19):
biggest questions we've ever had.
So basically trying to understand the multiverse is pushing the boundaries of what we know
and what we can even imagine.
Absolutely.
And even if we never actually travel to another universe or meet another version of ourselves,
just trying to understand it is giving us incredible insights into the cosmos and our
place in it.
It really shows that the universe, or I guess I should say the multiverse, is full of wonder
(10:43):
and mystery and possibilities.
And even if we don't find all the answers, just asking the questions and exploring is
what makes it so fascinating.
I totally agree.
It shows how curious we are as humans and how much we want to understand the world or
I guess the world's around us.
So to everyone listening, if you're intrigued by this idea of a massive multiverse with
endless possibilities, keep looking up at the stars, keep asking questions, keep exploring.
(11:08):
We're just at the beginning of this journey and who knows what amazing discoveries are
waiting for us.
And don't forget to subscribe to Cosmos in a Pod for more deep dives into the universe
and check out our YouTube channel for some awesome visuals.
Thanks for joining us on this cosmic adventure.
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