I've been lucky.
I have lived an extraordinary life,
exploring the universe and attending the odd party or two.
But imagine I could go anywhere and see anything,
that would be the most amazing opportunity of all.
Join me on a fantastical trip to my favorite places.
After all, why should astronauts have all the fun?
Every journey has a beginning,
and my own had a very difficult start.
At age 21, I received a life-changing diagnosis.
Doctor said a disease would steal my independence,
and then my life.
So I decided to devote with time I had left
to studying something truly worthwhile.
We've all seen computer animations of the big bang.
The big explosion, the flying galaxies, and then us,
but that's not right.
It was far more elegant and strange.
To see what really happened,
I'm going to wind back time.
As we go back, everything converges.
Space itself is shrinking,
unwinding the work of 200 million lifetimes,
until finally we reach a point of infinite density,
the beginning of not just space,
but time as well.
This is my life's obsession,
the big bang.
There are no fireworks.
Light won't exist for hundreds of thousands of years.
Our universe begins in darkness, not in light.
And time has began to flow forwards,
so the big bang must had caused itself,
because without time, nothing can had come before it.
All around us,
heat and energy are spreading at incredible speed.
There are slight imperfections,
some parts hotter than others.
In a billionth of a second,
it's grown from smaller than an atom
to a billion kilometers.
This rapid inflation can't last forever.
The universe is settling into steadier growth and cooling.
380,000 years after the big bang,
the light switch of the universe is thrown.
A flash so brightly we'll still be able to detect
in 14 billion years.
I predicted that this flash will contain fluctuations
preserved from the big bang.
Our universe,
a magnified version of its earlier tiny self.
The tiny imperfections present then
are now causing the universe to expand at different rates.
Everything that exists, planets, stars, galaxies,
and even us, are formed from these imperfections.
I am still on the same journey I began years ago.
Just as the expanding universe slowed,
so did the progress of my disease.
I have been lucky to live
to see some of my predictions confirmed.
That first flash of light we saw
is now called the cosmic microwave background.
You hear it in the crackle of a radio,
and see it in the static of a television.
It reveals wrinkles in the beginning of time,
which is why I believe perfection is overrated.
Nothing in nature is perfect.
If it were, we wouldn't exist at all.
Any good adventure means taking a few risks
even if your reputation is at stake.
Years ago, I made a very public bet
with fellow scientist Kip Thorne
about one of the most mind-boggling phenomenon
in the universe.
It was a bet I would live to regret.
People always ask me what would happen
if you fell in a black hole.
Well, there is only one way to find out.
Hidden in the center of our galaxy by thick dust clouds
lies one of the more extra ordinary things in the universe.
Sagittarius A Star,
a black hole with the mass of 4 million suns.
It bends light around itself like a cosmic lens.
So massive and dense that it warps space time
into an infinitely deep well.
Its gravity is so strong,
not even light can escape.
My bet was about what happens to things
sucked into the warp touch of reality.
The nearer we get, the stronger gravity pulls.
Harder on our front than our back.
Too strong and it will stretch us out like spaghetti.
Hopefully, we won't get turned into pasta.
I'm going to need some serious power
to fight a tide of gravity.
Go any deeper, cross the event horizon,
and it'll be the last trip I ever make.
Nothing escapes out of a black hole,
or does it?
Eventually, I realized something could.
It became known as Hawking radiation.
You see, space isn't actually empty.
Virtual particles and antiparticles
are popping into existence all of the time,
and cancelling each other out.
At the edge of a black hole, one particle might fall in,
but the other could escape out into space.
This would bring energy from the black hole,
and eventually cause it totally disappear.
So, I bet that everything
that had ever fallen into the black hole
would be lost for good,
but that causes a huge problem.
You see, you can think of the universe
as a giant data file which constantly changes
as one event follows the next.
But if black holes can destroy part of this data,
then the entire file becomes corrupted,
and both the past and the future of the universe
becomes uncertain.
Eventually, I realized this must be impossible,
so I lost the bet.
My latest theory is that the data is not lost,
but preserved in turbulence around the black hole
like a finger print,
so the universe is safe for now.
But if you ever find yourself heading
for your own personal black hole,
keep an open mind and take your chances.
You will find a way out of it in the end.
Our next destination reminds me of being a young child,
full of wonder.
Gazing at the stars,
I always imagine there was someone up there
looking back.
As I grow older, I am more convinced than ever
that we are not alone.
After a lifetime of wondering,
I am helping to lead a new global effort to find out.
The Breakthrough Listen Project
will scan the nearest million stars for signs of life.
But I know just a place to start looking.
In recent years,
we found thousands of planets outside of our solar system,
some are burning hellscapes of fire and lava.
Others are solid diamond,
bathed in deadly X-rays from a dying star,
but some are more like home.
Incredibly, we found one only 16 light years away,
right on our doorstep.
Gliese 832C, one of my favorites,
and one of the closest habitable world candidates
discovered so far.
It's a breathtaking sight,
a super Earth five times more massive than ours.
Here, a year last only 36 days.
Its atmosphere could be thick,
smothering the surface in super-heated smog.
Or worse, the gravity of its nearby sun
could lock the planet's spin,
one side always facing the sun.
Perhaps not such a good place for a picnic after all.
But if 832C has escaped such fate,
this planet could have Earth-like temperatures.
With abundant liquid water,
and where there is water, there is very often life.
Plants here wouldn't be green.
Photosynthesis from the sun's red light
would produce purple or black foliage.
There could be animals too,
perhaps intelligent ones.
From Earth, we can see what life is on 832C.
But if intelligent life has evolved here,
we should be able to hear it.
This planet is in range of the Breakthrough Listen Project.
Using the world's most sensitive radio telescopes,
what might we hear?
Maybe an alien opera,
or perhaps a phone call home.
One day we might receive a signal from a planet like this,
but we should be wary of answering back.
Meeting and advanced civilization
could be like Native Americans encountering Columbus.
That didn't turn out so well.
Time to leave I think.
Finding intelligent life
would be the greatest single discovery in history.
It would force us to change.
We would have to give up the idea that we are unique,
and start acting with more compassion and humility.
At school, I was never more than halfway of my class.
I like to think it was a very bright class.
I preferred spending time taking things apart
to see how they worked.
Today, I study the machinery of the universe
and surprises are every where.
When I'm in need of inspiration,
I often look to my favorite planet,
a speck of light in the night sky
that turns out to be one of the most
spectacular destinations in the solar system,
Saturn.
I have no doubt that in the future,
it will be a massive tourist hot spot,
complete with hotdog stands and screaming children.
But for me, it's the most beautiful cog
in an intricate machine.
The rings formed by Saturn's immense gravity look calm,
but trust me, that's an illusion.
They are immense boulders of ice and dust,
racing at 40,000 miles per hour.
A cosmic master race, complete with all the crashes.
And there are enormous ripples
caused by comet striking and tilting the rings.
But by catching or deflecting comets,
Saturn could be acting as a shield,
protecting the inner solar system from cosmic debris,
safe guarding life on Earth.
Saturn also shelters more than 60 moons,
like Enceladus.
Iridescent bloom skew from the surface
hundreds of miles into space.
Saturn's gravity pushes and pulls
on this little moon constantly,
heating it through friction, giving it a cosmic workout.
These aren't smoke or rock, but water vapor.
Thanks to Saturn,
Enceladus seems to have heat, water, and organic molecules.
It could harbor alien life hidden in subterranean oceans.
Saturn might have helped life develop on Earth too.
When the galaxy was forming,
Saturn acted as a sort of cosmic counter balance.
Its gravity stopping Jupiter from spiraling into the sun,
taking all the planets with it,
Earth included.
We may owe our very existence to Saturn,
something that as I child,
I would have been delighted to know.
Back then, I remember a friend
who bet a nut or bag of sweets
that I would never amount to anything.
I don't know how the bet was settled,
but I've learned the curiosity can take you to the stars.
And when you get there, who knows what you might find?
Like Saturn, the universe is full of surprises.
I am excited to show you my final choice.
Of all the places in the universe,
this is my absolute favorite,
a world of extra ordinary beauty
and breathtaking diversity.
Best of all, the journey succinct.
This remarkable planet gave us life,
and continuous to support us even as we do it great harm.
Here, I am spoiled for destinations.
I recluse to visit the cradle of humanity.
Journey into the heart of the planet,
or back into the mists of time.
But where I am heading is far more special to me.
It's inspired me to do some of my best work,
given me many happy memories,
and some sad and unfortunate places.
My home away from home, Santa Barbara, California.
In 1974 Cal Tech offered me a job in California,
and I jumped at the opportunity.
In the sun with my only family,
it was a world away from the great life of Cambridge.
I have traveled the globe,
but I've never found anywhere quite like this.
Many of my happiest days have been spent here,
watching the waves roll in.
It's a place with abundant life.
The largest animals that have ever lived
pass here on their epic annual voyage.
It's a truly inspiring place to be.
And it even has a beach club for theoretical physicist,
the Kavli Institute,
the perfect place for blue sky thinking.
It was here, overlooking the endless pacific ocean,
that Tim Hurdle and I developed a radical theory.
We've proposed a boundary condition of the universe
was that it has no boundary.
In essence, that the laws of physics would hold true always.
Everything in the Universe,
determined by a set of unchanging laws,
is not a big bang,
completely self-contained.
When you think of the universe like that,
it's easy to see how truly unique a place like this is.
It depends on the whole series of cosmic coincidences.
For instance, if the moon had never formed,
the Earth's spin would be less stable,
and there would be catastrophic shifts in the seasons,
not great for a beach town.
And if the charge of an electron was set
just slightly differently,
then stars wouldn't burn to give us light.
There would be no California dreaming or sun tans.
If gravity were just a touch weaker,
matter wouldn't have concealed into stars and planets.
So forget about beautiful beaches.
There would be no Earth or solar system.
And if the rate of expansion
after the big bang had been any smaller,
the universe would have recollapsed
before it ever reach its present size,
so nothing would be here at all.
In fact, most outcomes would give rise universes
that although beautiful
would contain no one able to wonder at their beauty.
So next time you find yourself thinking about your life,
please don't take it for granted.
Take a moment to marvel
at all of the wonders that allow you to exist,
all the incredible things that happened
just so you could be here
to enjoy your own favorite places.