NEIL deGRASSE TYSON: In 1930, a farm boy with a passion for the universe
notices a tiny dot moving across the night sky.
He discovers Pluto,
four billion miles from the sun and cloaked in darkness.
Pluto is a mystery.
Our best images are nothing more than a blur.
And many scientists are arguing over whether it's even a planet.
When we fly our spaceship to Pluto,
we'll arrive at a round world.
I'm able to use the word "world" if you like, but planet?
TYSON: The scientific debate over Pluto has even caused a media frenzy.
I'm sorry, I thought planets
might be one of the constants in life.
TYSON: Pluto lovers of America have taken to the streets.
Pluto forever!
TYSON: What is Pluto?
A new mission to the far reaches of the solar system
promises to answer this question and more.
It's true first-time exploration.
Pluto is going to be completely revealed in all of its glory.
TYSON: Join me, Neil deGrasse Tyson,
on a journey to explore America's favorite planet.
ALL: Hi!
TYSON: And find out why some people are blaming Pluto's problems on me.
So, how do you feel about Pluto, Dr. Tyson?
TYSON: These are "The Pluto Files," next on NOVA.
Major funding for NOVA is provided by the following...
TYSON: JOFor more than 75 years, theng great stage of our solar system
had a familiar cast of characters,
nine players in all.
We even memorized their names.
Mercury, Venus, Earth and Mars...
the rocky planets.
Jupiter, Saturn, Uranus and Neptune...
those gas giants.
And all the way out to the very edge of our solar system,
perhaps the most popular player of all,
a lonely little misfit, planet Pluto.
But recently Pluto lost its starring role,
and some folks are blaming that on me.
I, Neil deGrasse Tyson, director of the Hayden Planetarium,
in New York City, have been accused of being...
a Pluto hater.
Back in 2000, when my colleagues and I were designing this place,
instead of exhibiting Pluto here
with planets like Earth and Mars,
or up there with giants like Jupiter and Saturn,
we decided to boldly go where no planetarium had gone before
and put Pluto far, far away...
all the way downstairs
with a group of newly discovered icy objects
in the outer solar system.
If you look hard enough, you can find it right here.
Little did I know how much this decision would change my life.
My troubles began with the astute observation
of one young visitor.
I can't find Pluto!
TYSON: Who, just my luck, was overheard by an off-duty journalist
from the New York Times.
He decides this is a great story,
so he calls his Times colleague, science writer Kenneth Chang,
and he's shocked.
CHANG: Well, I was looking for Pluto and I couldn't find it.
You look everywhere, you see eight planets, not nine.
TYSON: A few days later, Chang's story hits the front page,
right beneath George W.'s inauguration.
The headline reads: "Pluto's Not a Planet? Only in New York."
I received angry e-mails...
and tons of letters,
especially from pissed-off third graders.
BOY: "Dear Natural History Museum,
Pluto is my favorite planet!"
GIRL: "Why can't Pluto be a planet?
"Please write back, but not in cursive
because I can't read in cursive."
MIKE NOVACEK: I thought, "Oh, my gosh,
"kids will probably go to this exhibit and cry
because Pluto's no longer a planet."
Could it be the final indignity
for the farthest and smallest planet in our solar system?
TYSON: Our exhibit had stirred up a media frenzy.
Pluto was, since 1930, a planet--
he had stature, he had friends.
You come along and say, "Da, da, da, da, da!"
DIANE SAWYER: Neil deGrasse Tyson,
you have left a void in the universe as big as Pluto.
I never wanted to kick Pluto out of the solar system;
I just wanted to group it with its icy brethren.
COLBERT: Are you saying Pluto should be
with its own kind, separate but equal?
Yeah, I guess it comes out that way, doesn't it?
Neil deGrasse Tyson has betrayed us.
He has thrown his weight around a little bit too much.
He's not the boss of the solar system; he's not the boss of me.
TYSON: If Neptune or Mercury had been reclassified,
I don't think anybody would have cared.
But the fact that it happened to Pluto
seems to make all the difference.
Pluto has a remarkable grip on the hearts and minds
of the American public and the press.
Hat.
Even my colleagues in astrophysics are still arguing
over what to do with Pluto and I don't really know why.
But I'm determined to find out.
This is the story of my journey.
These are "The Pluto Files."
My first stop took me to Cambridge, Massachusetts.
A visit to the hallowed halls of Harvard
just might help me make sense of this Pluto problem.
Welcome to the Harvard University...
football field.
I brought a few props along with me,
much to the surprise of my colleagues.
(grunts)
Astrophysicist Brian Marsden doesn't think Pluto is a planet,
while planetary scientist Mark Sykes thinks it definitely is.
And the esteemed historian of science, Owen Gingerich,
is looking for the middle ground.
SYKES: Okay, Neil, what are we doing here?
We're making a scale model of the solar system
right here on this playing field, so grab one of these.
Let's do it.
And let's do it.
TYSON: To evaluate Pluto's planetary status,
we need to take a closer look at how it compares
with the heavy hitters on the solar system team.
The planets are millions, even billions, of miles apart,
so this scale model can't accurately depict their distance
from one another.
But it can show their relative size.
If this eight-foot balloon represents our sun,
how does Pluto size up against the rest of the team?
Let's find out.
TYSON: Mark, first up...
Mercury. Mercury.
Represented by a bead.
In correct size relative to the sun.
Here we go.
TYSON: Miniscule Mercury may be small,
but its diameter is still twice as big as puny Pluto's.
Next up, Venus-- you have the honor.
Thank you.
TYSON: Venus, represented by this tiny rubber ball,
has a diameter five times as big as Pluto.
Earth. Earth.
TYSON: Earth, the big blue marble, is six times as wide as Pluto.
Earth and Venus were about an inch;
Mars would be about a half inch--
the sizes of these gumdrops, relative to the sun.
TYSON: But it still trounces Pluto three to one.
Jupiter. Jupiter.
King of the planets. King of the planets.
You have the honor. There you go.
TYSON: The largest planet, King Jupiter,
represented by a schoolyard kickball,
is a whopping 62 times as wide as pipsqueak Pluto.
Saturn. Saturn.
The size of a bowling ball
relative to the sun.
TYSON: Pluto doesn't fare much better
against my favorite planet, Saturn,
or its next-door neighbor.
Uranus. Uranus.
Represented by a bocce ball.
You ever play bocce?
No, I've never played bocce. Neither have I.
(both laugh)
TYSON: It would take 22 Plutos on a chain
to equal the diameter of one Uranus.
Croquet, anyone?
What do you have now?
Neptune. Neptune.
Why don't you have the honor?
TYSON: Big blue Neptune is 21 times as wide as Pluto.
Last and least?
And not least.
We have Pluto.
Represented by a ball bearing
removed from a roller skate.
Ah.
Sometimes the most valuable things
are in the smallest packages.
There you go.
Excellent. Pluto.
TYSON: Pluto's diameter is just under 1,500 miles.
In fact, if it ever decided to visit America,
it would stretch only from California to Kansas.
No matter how you look at it,
Pluto makes a scrawny little planet.
Pluto's really puny, right?
But so is Mercury.
Pluto's a lot punier--
1/20th the mass of Mercury.
Of Mercury.
GINGERICH: That's less than the mass of the moon.
Touchdown right there.
(laughing)
TYSON: If we were to keep score of Pluto's oddball traits
versus its planetlike characteristics,
how would it add up?
Brian thinks Pluto's puny size disqualifies it
from the planet team.
So he gives one touchdown and, of course, the extra point,
to Pluto the oddball.
This is ridiculous.
MARSDEN: It's not ridiculous.
TYSON: Mark disagrees.
For him, size is less important than shape.
Pluto, like every player on our planet team, is round
and not potato-shaped like nearly all asteroids.
This sequence of images taken by the Hubble Space Telescope,
shows Pluto as a sphere with a textured surface.
SYKES: When we fly our spaceship to Pluto,
we will arrive at a round world that has an atmosphere,
that has bright and dark areas on the surface.
And it will look much more like
objects we call planets
than these little irregular inert objects we call asteroids.
So, roundness... you give it a full touchdown.
Yeah.
Two touchdowns.
(all laughing)
TYSON: But then again...
We all know Pluto's got this really weird orbit.
First of all, it's tipped.
The most tipped orbit.
What's that worth to you?
MARSDEN: Not too much.
A field goal; not quite a touchdown.
That isn't really the problem.
I think the problem was crossing the orbit of Neptune.
TYSON: Pluto's orbit isn't just tipped, it's highly elliptical--
not nearly circular like other planets--
which actually forces Pluto
to cross the orbit of another planet.
That's bad.
That is really bad. Nobody else does that.
There you go, touchdown right there.
Another seven points for the oddball team.
One way you might define a planet
is that it ought to have a moon,
but of course Mercury and Venus don't have moons.
And guess what?
Tiny little Pluto does.
In fact, it has three.
One of those moons, Charon, is so large compared with Pluto
that they both orbit a point in space in between them.
Which might make you wonder, which one is the planet?
The idea of planets orbiting planets isn't really so foreign.
We see many double stars out there
and we see galaxies orbiting galaxies.
The solar system is such a complicated place,
it's very important to understand
there is this richness out there.
So, Brian, if we go there
and we find out Pluto has mountains or craters
or an atmosphere,
it's got world properties that match other objects
we are happy to call planets.
I'm able to use the word "world" if you like, but "planet"?
TYSON: So, then, what is Pluto?
Four billion miles from the sun,
our best images of Pluto and its moons
are nothing more than a blur.
By analyzing the light reflected from Pluto's surface,
planetary scientists think that a day on Pluto
might look like this:
an icy, frosty winter's night in the Arctic;
the sun a tiny pinpoint in a pitch-black sky;
wispy clouds and fog visible on the horizon;
the temperature about 300 degrees below zero.
No spacecraft has yet visited Pluto.
Until one does, it will remain a mystery.
Both of you are wrong.
And no scoreboard today is going to change that.
(explosion)
It was time for me to take a closer look
at why an oddball like Pluto
was considered a planet in the first place.
It's a tale that begins back in 1894
when a New England aristocrat by the name of Percival Lowell
built a private observatory near Flagstaff, Arizona,
with one goal in mind: to find life on Mars.
After years of searching in vain,
Lowell turned his attention to an unsolved mystery:
the hunt for a distant planet
whose gravity seemed to be causing disturbances
in Neptune's orbit.
He called this hypothetical object Planet X.
Lowell spent the rest of his life trying to find it
but never did.
After his death,
the task was given to the unlikeliest of planet hunters,
a self-educated farm boy who attended a one-room schoolhouse.
Clyde Tombaugh's first job in astronomy
included cleaning telescopes and sweeping up
at the Lowell Observatory.
He spent the rest of his time searching
for the mysterious Planet X.
Every few nights he placed a photosensitive glass plate
on the telescope,
securing it so it would not shift.
Then he exposed the plate for two hours to the universe.
During that time the motorized telescope slowly moved
to compensate for Earth's rotation.
Several days later he'd retrace his steps,
taking pictures of the same section of the sky
he had photographed earlier.
Then, using an ingenious device called a blink comparator,
Clyde Tombaugh aligned the two images
to carefully examine their differences.
The blink comparator enabled him to shift back and forth,
searching for the subtlest of changes.
Although the human eye is good at spotting differences,
finding a dim celestial object billions of miles away
was a daunting task.
After searching for almost a year,
a determined Clyde finally found a tiny dot
slowly moving across the night sky.
Can you see it?
Here it is.
A month later the Lowell Observatory proudly announced
that a young assistant had fulfilled
Percival Lowell's dream.
Clyde Tombaugh had finally found Planet X.
The day after the announcement,
the news hit the front page of the New York Times.
Soon the discovery was heralded worldwide.
But the new planet needed a name.
Across the Atlantic, an 11-year-old English schoolgirl
would come up with one.
On March 14, 1930, Venetia Burney's grandfather,
a librarian at Oxford, was reading the morning newspaper
and came across the story.
An American has just discovered a new planet.
I wonder what they'll call it.
TYSON: Venetia had just finished studying the Roman gods
and jumped at the opportunity to name it
after the god of the underworld.
They could call it Pluto.
Pluto.
Perhaps... yes.
TYSON: Her grandfather thought that was a splendid idea,
so he wrote a note to the Lowell Observatory.
The director at Lowell liked it,
especially because Pluto's official symbol
would be the overlapping letters P and L,
the initials of the observatory's long-gone founder,
the man who started the search for Planet X, Percival Lowell.
For most Americans,
the name "Pluto" didn't exactly conjure up affection.
It was associated with a well-known laxative
called "Pluto Water," a popular product that promised
"relief from constipation in 30 minutes to two hours."
Its slogan: "When Nature won't, Pluto will."
But the name would soon get a makeover...
And it would come from a young animator
by the name of Walt Disney.
Shortly after planet Pluto was discovered,
the fledgling Disney Brothers Studio
came up with a new character...
(barking)
a playful bloodhound named Pluto the Pup.
Walt probably wasn't thinking about constipation
when he named Mickey's new pal back in 1931.
My journey would lead me south to a magical place
to meet with a celebrity on a tight schedule.
Pluto! Hey!
It's great to see you!
Thanks for making time for this.
Can we pose for a picture?
Was Walt thinking planet when he gave his pup a name?
Maybe Roy Patrick Disney, Walt's great-nephew,
can help answer this question.
I wonder whether Walt jumped on the opportunity
to name this new character after this new cosmic object.
Is there any evidence for that in the archives?
There's no direct evidence.
There's a lot of anecdotal evidence.
I think it's fate; I don't think it's an accident.
You feel deep inside that Walt was thinking of the planet.
Yes.
He was fascinated with space and space exploration
and Walt did four TV shows about space
and all of them made space exploration and science
accessible to kids, including myself.
When he did his Man in Space series in 1956, '57,
America wasn't committed to a space program.
I know for a fact that many people who wound up
working at NASA were inspired to do so
by watching those television shows.
He made learning fun.
TYSON: I am certain Pluto the Dog
added some kind of warm and fuzzy feeling
for this cosmic object.
Cosmic objects don't normally trigger
warm and fuzzy feelings.
Pluto, have you ever looked through a telescope before?
No?
I brought one.
Isn't it cool?
Now, it's daytime, so you can't see much,
but let me show you how it works.
What do you think of that?
Did you see something?
You did? Try again.
TYSON: Whether or not Walt was thinking about the cosmos
when he named his dog doesn't really matter.
Good boy! Good dog!
The seeds were sown for the tiniest of planets
to get the kind of attention no other planet had,
all because of this lovable pup.
But I shouldn't give credit to the dog alone.
Next stop on my journey: Streator, Illinois...
the hometown of Clyde Tombaugh.
They love him so much, Main Street is named after him.
There's a mural in the center of town
that compares his discovery of Pluto
with the accomplishments of Copernicus and Galileo.
His life is chronicled at the local historical society,
where one of his homemade telescopes is on display.
There's even a plaque dedicated to him in front of city hall.
Clyde is a local hero.
Just about everyone around here can tell you his life story.
Next victim-- I mean customer-- please.
(laughing)
How you doing?
Doing well.
TYSON: Right now I'm on a pilgrimage, actually,
to try to understand
Clyde Tombaugh.
Clyde Tombaugh?
He's from Streator and he discovered Pluto.
TYSON: That's what I heard.
We're very proud of him, very proud of him, what he did.
TYSON: And you learned about him in high school?
Elementary school.
Third grade maybe.
Because that's when most people first learn about the planets.
And then... so, his name comes up
and you learn he's a local guy.
Streator boy makes good, so to speak.
Back in third grade I thought,
"Wow, that's astounding, from Streator, found Pluto."
TYSON: You feel some pride.
Oh, you bet.
Always did.
Always had something to point to as far as...
look at there, that guy, he discovered Pluto.
And he's from our area.
Walt Disney named a dog after him.
There you go.
So, how do you feel about Pluto, Dr. Tyson?
TYSON: In the eyes of the townfolk of Streator, Illinois,
Tombaugh's discovery is not only part of their history,
it's a piece of American history as well as world history.
It was the ancient Greeks who classified
what we call the moon, the sun, Mercury, Venus, Mars,
Jupiter and Saturn as planetes,
which means "the wanderers" in English.
They imagined Earth as a hub
around which these planets revolved.
In 1543, the Polish astronomer Nicolaus Copernicus
published his revolutionary idea
that the sun did not circle Earth
but instead Earth and its lone moon circles the sun,
along with the rest of the planets.
By the 17th century, the Italian astronomer Galileo Galilei
discovered Jupiter's four largest moons.
Meanwhile, Dutchman Christiaan Huygens
identified Saturn's rings and discovered Titan,
its largest moon.
Italian astronomer Giovanni Cassini one-upped him
when he discovered four more.
In the 18th century,
Englishman William Herschel discovered Uranus,
although he originally called it the Georgian Star,
after his king, George III.
Can you imagine a planet named George?
The British and French are still fighting
over who deserves the credit for predicting the location
of Neptune.
Some give the honor to John Couch Adams,
while others say Urbain Le Verrier deserves it.
But there's no doubt
that German astronomer Johann Gottfried Galle found it.
The discovery of Pluto finally added an American,
Clyde Tombaugh, to this short but esteemed list
of planet hunters.
So the folks in Streator, Illinois,
told me that in New Mexico there are still some Tombaughs there.
That's where Clyde moved after discovering Pluto.
Clyde's no longer with us,
but his 97-year-old widow and both his son and daughter
still live there.
So I decided I had to check it out.
Whoa, that's a lot of Tombaughs.
ALL: Hi.
TYSON: How many of you are there?
(laughing)
Hello, everyone.
ALL: Hi.
Annette Tombaugh, I'm Clyde's daughter.
What an honor, my gosh.
And this is my brother....
Neil, Al Tombaugh.
I'm Clyde's son.
TYSON: Al, pleasure.
And this is my mother, Patricia Tombaugh.
This is Clyde's wife.
It is an honor, hello.
Yes, I've been looking forward to this.
That could be... I don't know what that means.
(all laughing)
So, tell me about Clyde as a person.
He was the oldest of six children,
so he was born to help on the farm.
But he did not want to be a farmer.
ANNETTE: He had not had
the opportunity to go to college.
So what you're saying
is that he discovered Pluto
without ever having yet gone to college.
No, he was straight off e farm.
PATRICIA: Lowell Observatory
wanted somebody they didn't have to pay very much to do this job.
What do you think they pay you for finding a planet?
(all laughing)
ANNETTE: After discovering Pluto,
he got a college scholarship,
which he would not have otherwise had,
and, of course, he was supposed to be the big hero,
but he didn't feel like the big hero.
Dad was a little embarrassed about the fame.
He didn't like the limelight. He was humble.
Absolutely.
So what was he like just as a dad?
Was he like a weird dad?
Or did you think all dads were like that?
No, I knew he was very different.
One of the things, we did have
his grinding barrel to make telescopes in the kitchen.
This is the barrel that grinds glass
into the shape of a mirror.
Right-- yes, in the kitchen.
How mother ever put up with that I don't know.
We had grinding material in our food,
and Mother's trying to cook
around this situation.
Well, finally she made Daddy
move out of the kitchen and he got a shop.
(laughing)
Well, that... that's good.
TYSON: You mean to tell me you have
some of Clyde's original telescopes here?
Whoa!
These were his original telescopes.
Original telescopes built by my Dad.
Very hand-made.
Built out of old farm machinery,
car parts and whatever he could find.
We'll just push it out here. I'll help you push.
You bet.
So, Al, I don't recognize any hardware on this at all.
(chuckling)
The tube itself is probably part of an old grain elevator.
How about the base?
Well, the base is an old cream separator.
The axle is off an early model Buick.
So there's a Buick out there now without an axel.
This counterweight was probably a flywheel
from an early piece of farm equipment,
maybe even steam powered-- we're not sure.
I see a Coke can.
(chuckling): I love this.
So we got the open end of the telescope at the top.
And light comes down, reflects off the curved mirror
and light reflects back
and comes to an eyepiece under that Coke can.
And if we wiggle this Coke can a little bit like this,
there's the eyepiece.
We're ready to go. There it is.
All right, this isn't the only telescope I see back here, Al.
No, there's a couple others.
Let me pull this one out for you. Okay.
This has got to be the most homemade-looking telescope
I have ever seen.
Is this a lawn mower?
That is a lawn mower base.
This is what the family has called the grazer gazer.
He looked at this and said,
"It's got wheels, got a hale.
We need to put a telescope on that so I can push it around."
How to make a portable telescope. Absolutely.
He built it strictly on a utilitarian base
out of what he had, which was thin plywood
and miscellaneous pieces of wood.
This is insane.
This just rotates.
Exactly.
What impresses me is that he didn't care
what this thing looked like
as long as the image of the universe came out sharp.
Right, aesthetics didn't mean a whole lot.
(both laughing)
TYSON: On my way out of town, I stopped at a local church,
where there's a tribute to Clyde Tombaugh...
a stained-glass window that celebrates his life.
How many scientists have stained-glass windows of them?
It's more than just a celebration of his discovery.
Celebration of his life overcoming obstacles
that would keep most people down.
To me that's the message here.
After discovering Pluto,
Clyde taught astronomy and searched for another planet
in the far reaches of the solar system.
But as hard as he and other astronomers looked--
and they looked hard--
nobody found anything.
Most abandoned the search,
assuming there was nothing left to find.
But a few simply couldn't accept the prevailing view
that the solar system ended with Pluto.
I headed out to California to share a burger
with two colleagues who were convinced
there was something else out there.
Food's a-comin'.
TYSON: Mike Brown and David Jewitt.
Back in the 1980s, David started a search
that would put Pluto in a new perspective.
TYSON: So you start looking in the outer solar system.
That's kind of crazy because everyone knew
the solar system ended at Pluto.
Uh, it's a little crazy, but, you know,
the flip side is, it didn't seem reasonable.
It seemed peculiar that the outer solar system
would be this really, really empty place,
compared to the inner solar system, which we already knew
was full of planets and comets and asteroids
and all sorts of stuff.
Well, it's got to end somewhere, why not Pluto?
Yeah, I mean maybe, but maybe not.
TYSON: Despite what felt like impossible odds,
David teamed up with Jane Luu, then a graduate student,
and they started a search that would take a lot longer
than either one of them expected.
LUU: Why did it take so long?
Um, it was a matter of technology catching up
with the problem.
TYSON: il's to see distant stars
because they radiate their own light,
other celestial bodies are much harder to see.
That's because light has to travel all the way from our sun
to the object, reflect off its surface,
and then make the long journey back to Earth.
By that time it's barely visible.
David and Jane hoped that advances in digital detectors,
now standard in today's cameras,
would help them see a whole lot more.
That is, if there was anything out there to discover.
In 1992, after searching for five years,
they finally found something.
JEWITT: Here is the set
of discovery images for the first object.
Obviously it's the thing with the circle around it.
It didn't have a circle around it when we discovered it,
but it does now.
So you can see this object drifting
from this picture to this one to this one.
It's drifting slowly to the left.
Whereas most of the other objects
are fixed, stationary bodies in the background.
TYSON: When they found several more of these slowly moving objects,
David and Jane could finally declare that Pluto is not alone.
It's part of a region of the solar system never before seen.
David named it the Kuiper Belt after the astronomer
who proposed its existence in the 1950s.
Billions of miles wide,
the Kuiper Belt is chock-full of icy objects
in wide orbits around the distant sun.
They're the leftovers from the solar system's formation.
We theorize that more than four billion years ago,
our solar system consisted of bits and pieces of debris
colliding and sticking togetr into larger and larger chunks.
Eventually these chunks got big enough
for gravity to pull them into a nice round shape,
forming planets.
And as the planets got larger and larger,
their gravity vacuumed up nearly all the objects
in their path.
But in the end
there were still lots of bits and pieces leftover.
And they got flung out
to the far reaches of the solar system,
where they plunged into a deep freeze.
The discovery of this far-out region
of the solar system made many of us stop and think:
Is Pluto really a full-blooded planet
or just another Kuiper Belt leftover?
It didn't make any sense anymore to think of it as a planet,
because it fits so well
with this new population of Kuiper Belt Objects.
MARSDEN: We all considered
Pluto was strange at that time,
but we didn't know how to resolve this.
TYSON: And frankly, many of my colleagues weren't ready
to mess with America's favorite planet.
We all knew Pluto was an icy object
just like everything else in the Kuiper Belt,
but it was still the largest one in the neighborhood.
That is, until my other dinner companion, Mike Brown,
came into the picture.
I had just finished my Ph.D. and I was looking for something new
to move into and this seemed like the most obvious thing
that anyone could start working on.
This was an entirely new area of the solar system to go study.
So it was very exciting.
TYSON: Mike set his sights on doing something really big,
finding a Kuiper Belt Object larger than Pluto.
BROWN: I was determined
that there still must be something out there.
I had caught the bug of finding it.
TYSON: At the Palomar Observatory in California,
Mike had access to the largest digital camera on Earth.
The images were uploaded to Mike's computer,
where he analyzed them every morning.
With technology on his side, the discoveries just kept on coming.
BROWN: We found Quaoar, which is an object
out in the Kuiper Belt that's about half the size of Pluto.
The next year we found something
about three-quarters the size of Pluto
and the following year we found this thing,
and it was so bright and also moving so slowly--
moving so slowly because it was so far away.
I looked at it and I thought, this can't be right.
If it's that bright and moving that slowly,
it's the furthest thing we've ever found
and it's the biggest thing we've ever found.
It must be quite big, certainly bigger than Pluto,
and that's crazy.
TYSON: But it wasn't crazy.
BROWN: On the day that we publicly announced the discovery,
I had to make a decision what we were going to call it.
Is it a planet? Is it not a planet?
Is it the tenth planet?
Finally I had to say, "Okay, it's the tenth planet."
And I will tell you when everybody kept on calling me,
congratulating me for discovering the tenth planet,
I felt fraudulent the entire day.
Why?
William Herschel pointed his telescope
in the sky and found Uranus-- Uranus.
Uranus is a major part of the solar system.
And he found it.
That is a pretty big deal.
I discovered a little ice ball out on the fringe
and it just didn't seem
like the same magnitude of a discovery.
And I had been struggling with this for years.
Like, what do you do
when you finally find one bigger than Pluto?
I did not believe
that astronomers had the guts
to ever demote Pluto,
because it's just too publicly painful.
TYSON: And if tiny Pluto was a planet,
shouldn't Mike's discovery be one too?
So he forged ahead, ultimately selecting a clever name
for his discovery:
Eris, the Greek goddess of discord and strife.
Eris instilled jealousy and envy among men,
driving them to battle.
Mike's choice perfectly captured the destabilizing effect
Eris was destined to have on Pluto,
although he couldn't have guessed
what was about to happen next.
For the past century,
the IAU, the International Astronomical Union,
has been in charge of naming celestial objects.
But it couldn't approve the name of Mike's discovery
without knowing if it was a Kuiper Belt Object
or the tenth planet.
This posed a problem
because the word "planet" had not been formally defined
since ancient Greece.
Clearly our knowledge of the solar system has expanded
since then.
So committees were assembled
to come up with a new definition,
the last of which was headed by my friend from Harvard,
Owen Gingerich.
So what we proposed was that planets should be round
and going around the sun.
So, massive enough for the gravity to shape them
into a nice round form.
That's right.
TYSON: Under this definition, Pluto would remain a planet.
Mike Brown's discovery would be one too.
And as new discoveries are made in the outer solar system,
the planet count could go up.
GINGERICH: We realized
that doing this would bring scores of planets.
Into the accounting of planets in the solar system.
That's right.
TYSON: But when the definition was proposed in Prague
at the 2006 IAU conference,
many scientists were dead set against it.
A rebellion was brewing and things were getting ugly.
TYSON: Just to clarify,
your original suggestion got overturned within days.
GINGERICH: Our recommendations were rather pushed to the side
and a new kind of definition came about
in the final voting at the union meeting.
TYSON: A new definition that included the following line:
"A planet must clear the neighborhood around its orbit."
Pluto travels in a crowded neighborhood
littered with thousands of Kuiper Belt Objects.
It's simply not massive enough to clear them out of the way.
BROWN: In the definition that the IAU came up with,
eight major things which dominate the solar system
are planets.
They're all big.
They go in circular orbits in one disk around the sun,
and everything else is on these other crazy orbits
much smaller; those are not planets.
That concept is a rock-solid concept.
TYSON: And when this new definition went to a vote
of the members present, it was a slam-dunk.
(trumpet playing taps)
After 76 years, Pluto was no longer a planet.
COLBERT: I'm sorry,
I thought planets might be one of the constants in life.
But scientists just love change more than anything else.
Well, I'm sorry, that's not change I can believe in.
The whole underpinnings of what we understand as science.
Is gravity real or do we just have sticky stuff on our shoes?
I mean, the whole thing.
(trumpet continues playing taps)
I couldn't believe it.
I couldn't believe that that was the vote that happened,
but when that vote happened,
I knew exactly what was going to happen next.
Supporters of Pluto are speaking out,
trying to help it regain planet status.
MAN: ¶ Rock on, Pluto, you'll always be a planet to me... ¶
TYSON: Pluto lovers of America did not take the IAU decision lightly.
At New Mexico State, where Clyde Tombaugh had taught,
students took to the streets.
Go, Pluto! Pluto forever!
TYSON: The New Mexico legislature declared
Pluto was still a planet within state borders.
MAN: ¶ No matter what it says on the chart ¶
¶ You'll always be a planet in my heart... ¶
TYSON: And Illinois soon followed,
spurred on by efforts led
by the concerned citizens of Streator.
MAN: ¶ Rock on, Pluto! ¶
So I've got in my hand this... legislation
passed by the 96th general assembly
here in the State of Illinois.
Yes.
No one's got a problem
with declaring March 13th Pluto Day,
the anniversary of Clyde Tombaugh announcing
the discovery.
Who could argue that?
It's this part of the resolution that says
when Pluto passes overhead,
(chuckling): overhead of Illinois's night skies,
that it be re-established with full planetary status.
That's audacious.
That's saying, "Forget the scientists,
this is Illinois."
Yeah, this is Streator.
And don't mess with Streator.
And don't mess with us, yeah, there you go.
TYSON: Back at the barbershop, the guys made it clear where they stand.
BARBER: I still believe
it's a planet.
They can't make me think any different.
(laughing)
TYSON: But next door at the Country Cupboard,
locals questioned the decision.
I was very disappointed.
Disappointed in the result
or how they got the result?
Both.
You can't change scientific fact or definition
with a hand count.
You're a scientist.
Since when do you take a vote on... on scientific fact?
TYSON: But it wasn't just hometown folks
who disagreed with the decision.
Just a few days after the vote, this petition,
signed by hundreds of planetary scientists, hit the Internet.
It says: "The undersigned do not accept the IAU definition,
and they refuse to use it."
Period.
The last stop on my journey would be a visit
with a planetary scientist who proudly signed that petition,
one of the world's leading experts on Pluto, Alan Stern.
He's been mad ever since we opened our new exhibit
at the planetarium.
And he sure isn't pleased with the IAU.
You're late.
Ready for this?
Ready as ever.
TYSON: I can't wait to hear what Alan's got to say
about Pluto's demotion.
STERN: I think that the IAU has confused people,
because their definition produces such illogical results.
What I really like is what I call the Star Trek test.
When Kirk and Spock show up orbiting an object,
just by looking at the picture of it, they know it's a planet.
In an IAU world, Spock would have to come back and say,
"Captain, let me survey the entire solar system,
"determine whatever objects are there.
"I'll integrate the orbits overnight.
I'll get back to you."
It's not that hard.
So you don't even care
about whether a zone is cleared
or some of these other parameters.
No, that's all about location,
and location is for realtors, not scientists.
(laughing)
I don't think it counts at all
in terms of what it means to be a planet.
TYSON: So then, what is Pluto?
According to Alan, it's not just a Kuiper Belt Object.
It's not a lonely oddball either,
and it's definitely not demote-able.
It's simply a new kind of planet, a dwarf planet,
and it turns out there's lots of them.
It looked like the solar system consisted
of four terrestrial planets, four giant planets
and misfit Pluto,
but today, instead we see a solar system
with four terrestrial planets, four freakishly giant planets
and a whole cohort of Pluto-like objects
which turn out to be the dominant class of planet
in our solar system.
These are typically rocky and icy objects.
Many have atmospheres; many, possibly most, have moons.
All the things we're used to in the planets we're familiar with
but in miniature.
I think a decent analogy is,
when you see a Chihuahua, it's still a dog,
because it has the characteristics
of the canine species,
just in miniature.
TYSON: Why, then, are these pint-size planets
so much smaller than the rest?
The process of planetary formation
is a bottoms-up process.
Planets grow from small things to larger and larger things.
Dwarf planets were arrested
in the mid-stage of planetary growth.
They are actually planetary embryos.
Pluto and other dwarf planets would have grown much larger
had there been more material around them.
Why was there no more material for them?
That's a great question, and we don't know the answer to it.
TYSON: Many planetary scientists think
that dwarf planets were actually born
in another region of the solar system,
among the gas giants, where the food supply was plentiful.
But as the gas giants grew larger and larger
and migrated to their current positions,
the force of their gravity flung the tiny dwarfs outward
to the Kuiper Belt, where they reside today.
While there are thousands of objects in the Kuiper Belt,
they're spread millions of miles apart,
so far away from each other
that the dwarfs no longer come in contact
with the material they need to grow.
To study those objects
rather than objects that grew to much larger scales
will give us a great window
into the process of planetary formation.
MISSION CONTROL: Three, two, one...
We have ignition and lift-off.
TYSON: Alan and his team hope to open that window
when the New Horizons spacecraft, launched in 2006,
becomes the first ever to arrive at Pluto,
racing at a speed of 37,000 miles an hour.
Travel time-- 9 1/2 years.
Scheduled arrival-- 2015.
So this is the place.
This is Mission Control for New Horizons. Cool.
STERN: Yeah, the flight control team is monitoring
the data that's coming down,
looking at the health of the spacecraft
and sending instructions back up to basically choreograph
everything that happens on the spacecraft.
So how long do those instructions take to get there?
Like suppose it says, "Quick, turn left!"
Like, how long does that take?
Well, right now it would take about two hours and 12 minutes
for the instruction to get up there
and then after it's executed,
two hours and 12 minutes more for us to find out
that's what happened. To complete the round trip.
By the time it gets to Pluto...
It's going to be 9 1/2 hours. Round trip.
Yeah. So you better know well in advance
what you're telling this thing to do.
We try to make sure we do that.
TYSON: New Horizons has seven scientific instruments,
which will study Pluto's atmospheric composition,
its surface features, its interior structure,
as well as its three moons: Charon, Nix and Hydra.
So it seems to me that New Horizons, with its experiments,
will transform this icy ball out there into a world.
It's true first-time exploration.
We've never been to a dwarf planet,
and I think it will be as revealing
as when we first went to Mars
and no one expected craters and river valleys.
All right, so you had enough room for seven scientific instruments,
but I heard, like, there's more stuff than that.
Well, we've got a few mementos. Uh-huh.
Perhaps the most sentimental and noteworthy
are some of Clyde Tombaugh's ashes.
His ashes.
His ashes-- it's on its way to the stars.
The man is on his way back to the very planet he discovered
and he's due to arrive there
in 2015... That's great.
and that just blows my mind.
I'd challenge anybody to put that on their résumé.
TYSON: Finally its time to head back home.
But my journey isn't quite over.
I have one more thing to do, a promise to keep.
When I met Annette Tombaugh,
she told me she had never seen our exhibit
and asked if she could see it with me.
Of course I agreed.
I was a little nervous
about inviting Annette to the Rose Center,
because this is kind of where the public awareness
of the problems with Pluto began.
I'm excited.
I'm really excited about seeing the exhibit.
Of course I am still going to look for Pluto.
I think what we did here is sensible.
So let's hope this works.
(knocking on glass door) (laughing)
Hello. Hi!
Welcome to New York.
It's good to see you.
Oh, my goodness.
Welcome to the belly of the beast.
TYSON: I showed Annette where we exhibit the planets.
Then I took her downstairs to show her where we put Pluto.
And so here we have it.
It's there. (laughing)
Okay.
I don't see anything wrong with this presentation at all.
(kissing)
(both laughing)
So, after ten years, I can rest peacefully at night.
You can rest.
I wish it were a little bigger...
(both laugh)
And a little higher? (laughs)
TYSON: So can I offer you my view?
Not that you ask, but I have a view that's been stereotyped
but actually misrepresents my position here.
When you look at the richness,
this tapestry of information we now have about the solar system,
what I would vote for is
we recognize the true diversity of stuff that orbits the sun
and invent a new lexicon
commensurate with what our new understanding
of the solar system is, because it's no longer
just lights moving in the night sky.
Especially since we've discovered more than 400 planets
outside our solar system.
Maybe the definition of "planet" should consider
the rest of the cosmos as well.
After all I had seen and learned on my journey,
we decided it only seemed right
to add to our treatment of Pluto here at the planetarium.
So we attached this plaque.
And it says: Where's Pluto?
Some astronomers regard Pluto as a Kuiper Belt Object,
some call it a planet, and others think of it as both.
This confusion arises because a consensus has yet to emerge
on the scientific definition of "planet."
So are we ever going to agree?
No, I don't think we are.
I don't think agreement is necessary.
Culture will take its course.
These two guys are the cantankerous ones.
(all talking at once)
NOVACEK: Science is an exciting area.
It's an area of change.
Science is always changing, and you have to go with the flow,
and sometimes that means changing names
and reclassifying things that are held sacred, like Pluto.
Tyson has to understand something.
We don't care what it really is.
We just want to call it Pluto.
An astounding variety of life--
9,000 species of birds, 350,000 kinds of beetles,
28,000 types of fish.
Two million living species and counting.
Creatures that don't look anything at all like each other
are actually deeply connected.
How does evolution really work?
"What Darwin Never Knew," next time on NOVA.
On NOVA's "Pluto Files" Web site,
what's the best planet in the solar system?
Listen in as a range of opinionated astronomers argue
for their favorites.
Then vote for your own.
Find it at pbs.org.
Captioned by Media Access Group at WGBH access.wgbh.org
This NOVA program is available on DVD.
The companion book,
The Pluto Files, the Rise and Fall of America's Favorite Planet,
is also available.
To order, visit shopPBS.org, or call us at 1-800-PLAY-PBS.