In the known universe, there are realms of such extremes,
we barely know them.
We are only just beginning to explore.
This is not the endgame. This is the beginning.
We're beginning to venture into places we never knew we'd reach,
like deep space and our own deep oceans.
We've only mapped out a tiny fraction of the bottom of the ocean
and what we've found has been astonishing.
What if you could build a supernova right here in the centre of the target chamber?
And the most profound mysteries of science may be coming into view.
so now we're actually asking, what caused the Big Bang?
Is there any way we can find out what that was like?
Get ready, because we're crossing into the final frontier.
We may have split the atom,
landed on the moon,
and mapped the human genome,
but we're still a long way from being able to say we've got things figured out.
There are still places we've yet to explore,
frontiers beyond which we know nothing about.
Ultimately, I think we call something a frontier if it's inaccessible -
if it's difficult to study, if it's difficult to get to.
In the next hour, we'll be exploring the final frontiers,
starting with deep space and our own deep oceans.
We'll begin with the discoveries that have changed
what we know about our own solar system
and open our eyes to an unknown world beneath the waves.
And you'll see why those seemingly different places actually have a lot in common.
Then we'll show you the mind-bending new ideas about how our universe came to be.
We're on a voyage into the unknown.
space has been called the final frontier for a reason.
What keeps us from knowing is its size.
The universe is so immensely large, it almost makes no sense to talk about how big it is.
All those stars that you see in the Milky Way galaxy
are hundreds and thousands of light years away.
But little by little, we've found ways to cross those vast distances
by using tools like the telescope.
These optic marvels have brought deep space into focus
and they've shown us amazing things about our own solar system.
We used to think that Pluto was the farthest extent of our solar system,
but Pluto turns out to be one of a family of objects out there in the Kuiper Belt.
Not long ago, we thought our solar system began with the sun and ended with Pluto,
4.8 billion kilometres away.
Beyond Pluto, we thought space was empty.
But then, in the 90's,
astronomers saw things out past Pluto
in a completely unknown region of the solar system they called the Kuiper Belt.
The Kuiper Belt is a collection of icy, rocky things out beyond Neptune.
And there are many, many large objects out there.
One thing we've learned from the Kuiper Belt is the solar system's bigger than we thought.
I'll show you what I mean. Can I borrow that?
- sure. - Thanks.
If I use this basketball to represent the sun...
The real sun's about a million miles across,
but if I put this basketball sun down on a street corner in Los Angeles
and ask, "How far away is the Kuiper Belt?" It'd be really far down that way.
How far? Let's find out.
The Earth is about 93 million miles away from the sun,
which puts it about here, about 89 feet away from our basketball.
The Kuiper Belt, though, is still a long ways away. Let's check it out.
Ok, here we are about eight blocks away from our little basketball sun.
That's a little over half a mile.
But this is where we would find Pluto, which we now know is the beginning of the Kuiper Belt.
But where do we have to go to find the end? We gotta keep walking.
so here we are at the edge of the Kuiper Belt.
We're about 12 blocks away from our basketball sun.
In reality, that's about five billion miles and that very fact alone
means that the solar system is about twice as big as we once thought it was.
The Kuiper Belt nearly doubled the size of the solar system as we knew it
because it begins about 4.8 billion kilometres out from the sun,
and stretches out to about eight billion kilometres.
That's 3.2 billion kilometres of space for astronomers to study.
- All right, I'm gonna go stare at the sky. - All right.
It's what I like to do.
No astronomer has explored the Kuiper Belt more extensively than Mike Brown.
His observations of this distant expanse have actually redefined our solar system.
It was his discovery of an object called Eris that eventually led to Pluto
being demoted from the solar system.
Today, he's at the massive Palomar Observatory to study his latest discovery,
a spinning 1,600-kilometre-wide object more than 6.4 billion kilometres away, called Haumea.
And tonight... tonight only...
one of its moons is passing directly in front of it
and if we can watch it and measure it precisely when it happens,
we can learn all about Haumea.
On this night, Brown is hoping to witness the transit of a tiny moon called Namaka
across the surface of Haumea.
By timing the transit and measuring Haumea's change in brightness,
Brown can map the surface of this distant world.
The peak is, like, at 5:30 and then it goes until 6:30.
You're seeing so much of the saturation you can't tell what's going on.
This critical observation can only be made tonight.
Haumea is aligned at just the right angle to witness this distant event.
Mapping the surface will help Brown find out what Haumea is made of,
which is important,
since the objects in the Kuiper Belt
are leftover bits of material that never made it into the planets.
Understanding their composition could give scientists a never-before-seen look
at the pristine building blocks of our solar system.
What we see right now
has very little resemblance to what was here 4.5 billion years ago.
But if you go out and find this thing
that's been sitting in the freezer for 4.5 billion years
and take it out, you can really see what things were like back then.
If this observation isn't made tonight,
it will be 300 years until this event happens again.
We've been working for the past year
to calculate precisely when this was going to happen
and precisely where on Earth you had to be.
so we knew that tonight, right here at Palomar Observatory, it was the perfect time to do it.
But tonight, Mother Nature is not playing ball.
As the sun begins to set, a thick fog rolls in.
This was one of our best chances to really get a good look at it from here at Palomar.
so if we lose it tonight, it's gone forever.
(sighs)
Oh, Brazil's cloudy too.
That was our last good shot.
lt's up to us.
No. We're sunk.
Brown may have lost the battle tonight,
but his observations are helping us cross frontiers in deep space.
And there's a lot more work to be done,
because scientists think that our solar system doesn't end with Haumea
or anything else in the Kuiper Belt.
Beyond the Kuiper Belt, far beyond,
1 00,000 times on average the distance from the Earth to the sun,
is the Oort Cloud -
an enormous swarm of perhaps trillions of icy bodies, the comets,
which are left over from the earliest days of the solar system.
The Oort Cloud is incomprehensibly far away.
The inner edge of the Oort Cloud
is over 1 49 billion kilometres from the sun -
30 times further away than the Kuiper Belt.
Remember our model of the solar system,
with our basketball sun and the edge of the Kuiper Belt here, 1 2 blocks away?
Well, the Oort Cloud is a lot further away.
so far, l'm gonna need a car to get there.
Let's go.
OK, so there's two miles from the basketball sun.
There's four miles from our basketball sun.
1 0 miles...
..1 6 miles...
..21 miles...
Not there yet.
lt's a long way to the Oort Cloud.
32 miles.
Oh, getting close. Oort Cloud, dead ahead.
We're here.
so we've finally arrived - the inner edge of the Oort Cloud.
We're about 34 miles away from our basketball sun in downtown Los Angeles.
And this is just the inner part.
lf we wanted to go to the edge of the Oort Cloud, or the edge of the solar system,
it'd be another 1 ,700 miles that way.
The Oort Cloud forms a sphere around the solar system
and it's made up of lumbering chunks of ice called comets.
But the Oort Cloud is so far away and the objects are so small and dark
that we've never actually seen it.
so how do we know it's there?
Every once in a while, a comet will come streaking in to the inner solar system
with a type of orbit that scientists calculate
could only come from a place far beyond the Kuiper Belt.
The comets reside, a trillion of them or more, in the Oort Cloud, far from the sun.
Because they occasionally interact with each other gravitationally,
one can be thrown towards the inner solar system.
When that happens, this icy object blazes through the sky
in a brilliant show of cosmic fireworks,
just like comet Hale-Bopp did in 1 997.
But beyond this celestial show,
comets, and the distant reaches of the solar system they come from,
may have something important to tell us about Earth.
Because comets may be the reason why our planet has oceans.
Crossing frontiers in science means exploring revolutionary new theories.
We discovered that our solar system extends out billions of kilometres
to a frozen expanse called the Oort Cloud.
scientists, looking at that comet-riddled region, came up with a radical new idea.
sometimes scientists come up with a truly mind-blowing idea and you have to say,
''How could you possibly think that?''
And one of those questions is, where did the water come from on Earth?
We really don't think it started out here.
lt had to come from somewhere else.
OK, what's an example of getting water from space? A comet.
We know that comets contain a lot of water, in this case frozen as ice,
and there are plenty of comets.
And if you calculate how many comets hit the Earth when it was forming,
you get about the same amount of water in those comets as we see in the oceans.
Billions of years ago, as the solar system formed,
comets impacted the Earth and left their water.
The idea that comet impacts created our oceans
isn't so strange if you think of a comet as being something like a water balloon.
A comet can contain over 1 00 million tons of water.
And when they slam into the Earth,
again and again for millions, if not billions, of years,
it's not so hard to understand that, yes, our oceans could have been made by comets.
According to this theory, all the water in the oceans, rivers and lakes on the planet,
arrived onboard comets.
so why do some scientists believe this?
Chemical analysis of some comets that have swung by Earth
show the water inside them has the same chemical signature as the water here on Earth.
While this theory might tell us how our oceans got here,
surprisingly, we don't know much about the environment
that covers nearly three-quarters of the Earth.
For the most part, our oceans are virtually unexplored.
That's because the deep ocean is every bit as hostile as space.
Human beings are air-breathing, land-loving, and sun-loving creatures.
We're not designed to go down in a world of eternal darkness,
freezing cold, and pressure that will kill us.
By some estimates, we've explored just five per cent of Earth's oceans.
And since 7 1 per cent of Earth is underwater,
we really don't know much about this planet we call home.
The Earth's a pretty big place. so it's hard to understand just how little of it we've explored.
To put this into perspective, if we knew as much about this house as we do about the Earth,
that would amount to what's in this 9x9 box
and that's not a whole lot.
so let's see what we're missing.
We would have no idea about this room or this couch.
And this fireplace would be a total mystery.
We would have no idea about this kitchen.
And that just goes to show you that knowing so little about our oceans
means we know very little about the Earth.
The pressure of the deep ocean is what makes it so difficult to explore.
Water is surprisingly heavy.
The pressure just at the bottom of a swimming pool can be uncomfortable.
so deep in the ocean, it becomes extreme.
lf we dive 1 3,000 feet,
what you're seeing is more than 6,000 pounds per square inch of pressure.
lf you're not breathing at the same pressure as the water around you,
you get squished.
lt's really bad.
To put it in perspective,
if you're at one of the deepest spots in the ocean,
1 1 kilometres down in the Mariana Trench,
it would be like having 50 jumbo jets stacked on top of you.
Water pressure is the reason why we have more detailed maps of the moon and of Mars
than of the deep ocean.
Most of the world's oceans are deeper than two and a half miles.
And we have seen virtually none of the deep sea.
That much.
Little by little, however, scientists are finding their way down to the bottom of the sea.
They've done it by taking a hint from what may be nature's most ingenious invention.
Ever wondered why submarines are round?
Amazingly, they're modelled on one of nature's strongest inventions - the egg.
To prove this, let's bring in somebody who's a lot stronger than l am, my special eggbeater.
- All right. - OK, this is a raw egg.
l'm ready to break this thing.
- Can you break it? - l'm sure l can. Have you seen these eggs?
lt's pretty impressive. Let's see what you've got.
You're going down, Chicken Little.
Come on.
Why won't you break?
Come on, girlie man, crush the egg.
l want breakfast.
l think l resign.
Amazingly, the curved shape of an egg distributes force evenly all along the surface.
lt's very hard to break.
And that's why submarines can stand up to the enormous pressure of the deep ocean.
The right shapes and technologies
are giving scientists unprecedented access to the deep ocean
and offering us a glimpse of a landscape that's bigger and more majestic
than anything we see here on the surface of Earth.
The largest mountain ranges on Earth are beneath the sea.
The greatest canyons are beneath the sea.
Here on the surface, we marvel at mountains like the Himalayas and the Andes,
but these massive peaks are nothing compared to what's beneath the waves.
Basically, the single biggest geological feature on the planet
is a volcanic chain that's about 50,000 kilometres long.
lt's called the Mid-Ocean Ridge.
lt's a chain of volcanic mountains that runs 64,000 kilometres around the planet.
lt's like the seam on a baseball.
You start up in the Arctic Ocean and you come down between North America and Europe,
go all the way up into the lndian Ocean,
carries on across the bottom of the Pacific, south of Australasia,
comes up off the coast of Chile,
and runs all the way back up off the coast of Oregon and Washington
before it finally peters out.
And it's here along this ridge that new land is being created.
Molten rock is pouring out through this enormous crack
to slowly renew Earth's rocky crust.
The Earth is basically having a continuous facelift and that's why it's so beautiful.
The Mid-Ocean Ridge has also opened our eyes to a universe of strange creatures
that's changed what we know about life on Earth.
A century ago, scientists thought the deep ocean was lifeless.
We believed that for life to exist,
it needed light from an energy source, the sun.
And sunlight reaches down only 900 metres.
The average ocean depth is four kilometres.
ln this dark, cold, pressurised environment,
it's no wonder scientists considered it to be lifeless.
Then ocean explorer Bob Ballard stumbled onto something
that changed our understanding of biology and virtually all we understood about life on Earth.
l'm best known for finding the Titanic, but we knew it was there.
lt was our discovery of the hydrothermal vents that reshaped biology.
lt was our expedition to the Galapagos Rift
when we discovered this whole new life system on our planet.
lt was at a hot volcanic vent around three kilometres down
that Ballard discovered not just life,
but a thriving ecosystem,
full of creatures so strange they seemed alien.
There were blind shrimp,
albino crabs,
and huge clams.
lt was the life forms that we discovered there that really threw us for a spin.
They were bizarre. They were creatures we'd never seen before.
And one of the dominant organisms was what we call a tubeworm,
and these were six, eight feet tall.
And they had a human-like blood.
These huge tubeworms were completely new to science.
Nothing like them had ever been seen before.
But beyond that, this was undeniable proof
that life thrived in an environment we thought was inhospitable.
lt's showing you that life is much more creative than we ever thought
and that the probability of finding it elsewhere,
not only in our universe, but within our own solar system, has just increased dramatically.
Ballard's discovery not only changed what we knew about life on planet Earth,
it gave scientists looking for life on other worlds
an insight as to how it might survive and where they might go looking for it.
The discovery of entire ecosystems surviving in the harsh, deep ocean environment
rocked the world of science
and reminded us there's still a lot to learn about Earth.
To understand the Earth, first you need to study it.
And since most of it is beneath the sea,
we need to go beneath the sea to understand the Earth.
so far, we've found 200,000 of them living in the ocean,
but some scientists think there may be as many as 25 million marine species left to be found.
We make great discoveries, but most of our discoveries have been done by accident.
We were looking for one thing and found something else.
so you only have to imagine what else is waiting for us.
For years, the only way we could study life in the ocean was by hauling it up to the surface.
That might give us a good look at the animal,
but it doesn't tell us a lot about the environment it came from and how it survives.
But now, off the California coast,
researchers are testing a new probe that's designed to live on the sea floor
and study the tiny organisms that live there.
There's nothing like getting up at four in the morning,
throw hardware over the side we've spent five years building,
and, you know, hope it works.
For five years, ocean explorer Chris scholin has been building this probe,
the Environmental sample Processor, or EsP.
lt's a remote biological lab that will collect microorganisms
and lD them through genetic analysis.
The EsP will give scientists real-time information
on what's living at the bottom of the ocean
and other data like temperature and pressure.
The EsP will feed all this information to the shipboard command centre via cables,
where scientists will analyse the results.
No-one's ever been able to put a molecular biology lab at the bottom of the sea.
For us, that's really the brass ring. Get down there and do that.
Never been done, and so we're thrilled to give that a shot.
But that depends on whether the probe survives the 600-metre descent into an undersea canyon
off California's rugged Big sur Coast.
Well, there it goes.
Love it or leave it, it's on its way.
Five years of work comes down to this.
Today is the first time that we actually have run the entire instrument in a real setting.
lt can only simulate the real world to some distance
and then at some point, you've got to put it out there.
ls there some portion of the environment that we forgot about that's going to affect it?
As the probe descends, scholin and the crew monitor its progress.
Our depth now on the vehicle's about... close to 500 metres.
We've got another 1 50 to go, so we're getting close.
- There it is. All right. - All right!
We're on the bottom, plugged in, and we're gonna start running the instrument now.
so all the action's gonna go up topside into the van.
Hey, so it worked.
When we put things out here in the ocean, it's almost like we're on another planet
because you can't get to it, you can't touch it, and you kinda hope you're gonna get it to work.
The EsP represents a revolutionary new approach to our exploration of the ocean
and the plan for one of the EsP's future missions
is to drop it down around 1.5 kilometres to a volcanic vent off the coast of Oregon
and leave it there for an entire year.
For the first time, scientists will be able to continuously monitor life at the ocean bottom.
And because microorganisms are the foundation of any ecosystem,
scientists suspect it will reveal an ocean even more alive than we thought.
lt might even give us a way to find out if there's life elsewhere in the universe.
That's because the Earth may not be the only world with an ocean.
Enceladus is a moon of saturn.
We noticed its surface was rather smooth and made of water-ice.
Enceladus has always intrigued scientists.
This tiny moon, just 480 kilometres wide,
is covered in ice
and features huge 1 20-kilometre-long cracks running across the surface.
lt was along one of these cracks that scientists in 2005
saw something they didn't think possible.
What we weren't prepared for is when Cassini flew through the system,
it found this eruption of liquid water through the surface.
Three years after discovering these water plumes,
scientists flew Cassini down to within 22.5 kilometres of the surface of this distant moon
and through one of these eruptions.
They actually passed right through those plumes and found water.
They found dust particles.
And there's some evidence that there are organic compounds.
They found the water contained benzene and ethane,
as well as a number of different nitrogen compounds
that scientists think may have been the building blocks for life on Earth.
That begs the question.. might this ice world, merely 1,200 million kilometres from Earth,
also be an oasis for life?
The answer might come soon.
l think we'll be able to show for sure bacteria in the plumes of Enceladus.
And it seems like science fiction right now,
but the science fiction of today
is the basis of National science Foundation grants of the future.
But how would we find out?
searching for Enceladus's ocean would mean digging through kilometres of ice.
lt sounds impossible, but the roadmap down might be jingling around inside your pocket.
Put a penny on ice and it'll melt its way through.
That's because metals are great heat conductors
and gather energy from the surrounding atmosphere.
scientists could use this concept to get through Enceladus's ice.
We could send a probe that stays just above the freezing point
and the weight of the probe itself would help sink it down through the ice.
Then we could drop something like the EsP into these alien waters to look for life.
That's another reason for scholin's voyage.
The other thing we'll do is provide a home for some of the sensors
that people hope to look for evidence of life on other planets.
We're just gonna serve as a place for them to test their equipment
in preparation for space flight.
Finding extraterrestrial life remains one of our greatest goals.
But learning whether or not we're alone in the universe
isjust one of the many mysteries left to solve.
We're focusing a lot of attention on trying to bridge the gaps in our knowledge
about the universe itself.
And to understand these riddles, we're coming up with some mind-blowing concepts.
ln the last few decades,
scientists have made great strides exploring the deep oceans
and probing the boundaries of space.
But there are still many mysteries left to solve and the obstacles are still great,
especially out in the cosmos, where outer space is simply enormous.
One of my favourite statistics is that if the sun were about the size of the dot of an i on a page,
then the Milky Way would be the size of the continental United states, from New York to LA.
so think about the dot of an i in that vast space.
And that'sjust our galaxy, the Milky Way.
There are at least 1 00 billion more galaxies out there,
and they're all really far away.
Our galaxy and those other galaxies are filled with billions of stars,
but we've never been able to get close to any of them.
The nearest star is the sun
and at 90 million miles away, it's too far away to go there and bring a sample back.
We can't put a star, grab it out of the sky, put it in our lab,
and change its temperature, its chemical composition, its pressure.
We can't do experiments on cosmic objects.
Or perhaps we can.
What if you could design an experiment here,
where you could build a supernova right in the centre of the target chamber?
At the National lgnition Facility,
scientists like Ed Moses are putting the finishing touches on a device
that'll actually build stars here on Earth.
We put a lot of energy into a very small space for a very short time.
And when we do that, we can create conditions
that exist inside astrophysical objects, like the centre of our sun.
They'll do this by aiming 1 92 of the largest and most powerful lasers ever built
at a target inside this giant metal ball.
The lasers will ignite a nugget of frozen hydrogen and trigger a fusion reaction
that'll turn that hydrogen into helium.
lt's the same process that powers our sun and every other star in the universe.
That's the miracle of laser light.
We can focus it to very small spaces for very short periods of time,
get very high temperatures.
And when l say high, l mean as high as 800 million degrees.
scientists hope to be able to use these lasers to study the whole life of a star,
from its formation through its slow evolution
and on to what might be an explosive death, a supernova.
l think this is an exciting and very promising capability.
We'll learn how our universe works and we'll learn more about it.
The work being done at NlF will help give us a never-before-seen look
at some of space's most distant objects.
But what it won't do is tell us about space itself.
And in this vast expanse lies one of the biggest puzzles of our time.
The universe is expanding and scientists have no idea why.
The universe is getting bigger every day.
What we understand now is that the amount it's getting bigger is getting bigger every day.
The expansion of the universe is accelerating.
lronically, what this means is that as time goes on,
even though the universe is getting bigger, we see less of it.
How is the universe getting bigger?
Finding the answer has become one of the greatest quests in modern science.
Just a few years ago we were trying to measure
how much the universe is slowing down over time.
lt makes sense. An explosion happened a long time ago, the Big Bang.
scientists assumed the Big Bang would slow down
and gravity would pull things back together.
But that's not what they were seeing in the cosmos.
Astronomers think that the universe appears to be expanding at an accelerating rate.
Now, we have no idea what's causing this, so l'll let you in on a secret here.
Whenever astronomers don't know something, they tend to say ''dark''. Dark energy.
Even though scientists are baffled,
they know this thing called dark energy
makes up 70 per cent of what's out there in the cosmos.
lt's stronger than gravity
and may eventually be stronger than the forces that hold atoms together.
My body is held together by the electromagnetism in my atoms.
But what if the expansion of space increases and accelerates
and then even overcomes those forces?
Astronomers are calling that the Big Rip.
Although we don't know this will happen, it's a possibility that eventually
the expansion will get strong enough to rip apart atoms, to rip apart our very bodies.
Even matter will fly apart.
Not only has dark energy left scientists baffled,
there's another mysterious substance out there called dark matter.
Dark matter is seriously strange. lt's actually not made of atoms.
You and l are made of regular matter, and dark matter is something different.
so l don't think you could touch dark matter or smell it.
lt wouldn't interact with us the same way.
The only reason we know it's there is gravity.
scientists know dark matter must exist because they see its gravitational effect.
Without dark matter,
the stars in the outer reaches of a galaxy would fly off into intergalactic space.
ln other words, the dark matter is playing a crucial role in holding a galaxy together.
We know for a fact that dark matter permeates the Milky Way galaxy.
Dark matter is not something that's far away. lt's right here, in this room with us.
We are actually gravitationally attracted to it at this moment.
The problem is, how can you isolate a particle of dark matter?
What is it really made of?
Finding the answers to the mysteries of dark matter and dark energy
has become the Holy Grail of science.
Maybe our ability to travel faster than the speed of light
or to draw enormous amounts of energy from the universe
will stem, ultimately, from our understanding of what dark energy is and how it works.
The idea behind dark energy is simply mind-blowing,
but the most complex mysteries of the universe also seem to be the strangest.
Take, for example, the shape of our universe.
since we're limited in what we can see in the distant cosmos,
we can't be exactly sure what shape our universe takes.
Most scientists believe the universe is flat, but others believe it's doughnut-shaped.
some believe the universe is actually spherical.
From where we sit in the cosmos, it's difficult for us to get it all in perspective.
As l stand out here in this Kansas cornfield, everything looks flat.
And that might lead me to believe that the entire state is flat or the whole world is flat.
But if l could change my perspective,
l could see that Kansas is curved
and that l'm standing on a sphere.
That might prove to be the case with the universe,
because we can only see out 1 3 to 1 4 billion light years in any direction.
And the universe might be bigger than that.
And if it's bigger, it might be a different shape.
Crossing frontiers requires unparalleled ingenuity and cutting edge technology.
But when it comes to the big cosmic questions like how our universe started in the first place,
we have to dive head first into the theoretical.
And trying to solve those mysteries can tie our brains in knots.
ln spite of everything we want to learn about the universe,
there's one question that remains at the top of the list.
How did the universe come to be?
The Big Bang Theory says that space, time and everything else
was born out of a colossal explosion 1 3. 7 billion years ago.
But we know little about what lit the fuse.
The Big Bang is an incredibly powerful theory.
lt explains very well why our universe looks the way it is,
why the chemicals are the way they are.
But it's ultimately unsatisfying because the idea that something came out of nothing,
it has to be wrong.
lt just can't possibly be right. lt doesn't answer that.
so right now we're questioning what set off the Big Bang.
There are many ideas about what it was that banged all those billions of years ago.
But one theory's gained popularity among cosmologists..
the idea that the Big Bang occurred when two other universes bumped into one another.
One idea is that our universe came into being
when two multi-dimensional branes sort of kissed off each other
and gave rise to the four-dimensional space that we call home.
so what are multi-dimensional branes?
Brane. B-R-A-N-E, brane. After membrane.
We now use the word membrane, actually, to describe a universe.
lf you model our entire universe, all of space and all of time, as a sheet,
you can call that a membrane.
Well, maybe there are other sheets out there.
There are maybe ones that interact with us
and where they interact with us, they give our universe some energy.
The Big Bang may have been something like that.
lt may have been an interaction of two universes, two membranes,
and that gave the energy and the heat and the pressure needed to expand our universe
and create space and time.
so the Big Bang and our universe were the product of some multi-dimensional train wreck.
Let me just say now that when we talk about cosmology,
we're talking about things outside our human scale of comprehension.
There is no scientist that really gets this and understands it in a visceral way.
But in simple terms, it can be explained using bubbles.
Think of the universe we see as being confined to the surface of a soap bubble or membrane.
Now it's thought that in addition to our membrane, or our soap bubble,
there's another membrane that we can't see directly.
And sometimes these bubbles collide.
When that happens, the universe is filled with a tremendous amount of energy and radiation.
And that might be the explanation for the Big Bang.
As crazy as all this sounds, theorists have another strange idea.
What if instead of a universe, we lived in a multiverse?
Well, one idea of where the universe came from
is that, in fact, it's just one part of what you could call a multiverse
of perhaps endless universes that occur, possibly each with its own set of physical laws.
lf either one of these theories is right,
then everything we see out there in the cosmos isjust a small part of something much larger.
And if that's the case, then the frontiers of science just got a whole lot further away.
The word ''universe'' was meant to mean everything that could possibly exist,
everywhere you could possibly go.
But now scientists are really beginning to ask, are there other universes out there?
The fact that scientists can even ask that question is a testament to the times we live in.
We are on the cusp of answering some of the most difficult questions we've ever asked,
both about the cosmos and the planet we call home.
We're in this wonderful time of exploration
and both of these spheres have a huge number of questions that we have yet to answer.
scientists are poised to cross into the unknown.
On the ocean floor, they may finally unravel the mysteries of life on Earth.
And in the cosmos, they may finally solve the puzzle of how our universe began.
We're learning more about the world around us,
but with this knowledge come even bigger questions.
Each new discovery isn't putting an end to our curiosity, it'sjust making us more inquisitive.
That's the nature of the human spirit.
We won't stop trying to reach the final frontiers.