(male narrator) Is there really a face on Mars?
Is this the Eye of God?
Why is there a giant hexagon on Saturn?
When I first saw these pictures,
I thought, "How the hell do you get that?"
(narrator) What has astronomers blowing things up?
And why is one of Saturn's moons a Star Wars lookalike?
(Andy Howell) It looks just like the Death Star!
(narrator) Could the strange shapes of the universe now solve mysteries
that have haunted mankind since ancient times?
Ancient mysteries shrouded in the shadows of time.
Now can they finally be solved
by looking to the heavens?
The truth is out there,
hidden among the stars
in a place we call
the universe.
Of all the wonders in the ancient sky,
perhaps nothing mystified mankind more than the moon.
But what could explain the face that appears
on its silvery surface?
Was it a magic spirit
or one of many gods ruling the heavens?
Some say the face belongs to Cain the Wanderer,
son of Adam and Eve,
condemned to circle the Earth endlessly
for killing his brother Abel.
Other ancients saw things differently.
The man in the moon is only a man to us.
In other cultures--for example, East Asian cultures--
many people see other shapes or other faces.
In East Asian cultures,
it was thought that rabbits live on the moon,
and so the man in the moon is actually a rabbit.
(narrator) Why does this mysterious anomaly
look as it does?
Is there an answer in science?
The dark areas are ancient lava flows
that are reasonably flat.
And the bright areas are more mountainous regions
where there are lots of craters,
and they reflect the sunlight more.
(narrator) But what did the ancients make of the other imperfections
in the celestial sphere?
A star that suddenly brightened,
a comet appearing to streak through space?
The invention of telescopes 400 years ago
only deepened the mysteries,
revealing strange shapes everywhere.
(Walkowicz) When we look out into the universe
and we see shapes in the distant stars
or in other astronomical objects,
what we're really looking at is physics as the sculptor,
because the more detail that we get,
the better we can learn about the shape of that object
and the more detailed we can make our model of how it formed.
(narrator) For each of the odd forms we see,
its shape is the latest chapter
in the sometimes violent and often dramatic events
that seem to speak to us with a story.
Could this be the Eye of God?
700 light-years away,
the haunting image appears in striking variations
as modern telescopes photograph its details
in different wavelengths of light.
(Filippenko) It really just looks like an eye
staring down at you from space,
and if the celestial sphere is the home
of various gods or the single God,
well, gee, maybe this is the Eye of God.
(narrator) To our ancestors, the stars were great mysteries.
What were they made of?
What was their purpose?
In those earlier times, the view of the night sky
is that you had all these bright objects--
the stars, the planets--
as immutable, everlasting objects.
(narrator) The strange shape we perceive as an eye
proves that stars are not unchanging and everlasting.
Like humans, they have limited life spans.
This is an ordinary star in its death throes
emitting gently its atmosphere out into space.
The remainder of the star, its core,
is so highly energetic that it's emitting enough radiation
to light up this gas in space, almost like a fluorescent tube.
(narrator) When discovered by telescope in 1820,
the Eye of God appeared only as a fuzzy round shape,
similar to what planets looked like.
Astronomers called it and others like it
"planetary nebulas."
Today's astrophysicists call this the Helix Nebula.
Astronomers used to think that the Helix Nebula
is a coil in space,
and we see it end on,
so it looks like this.
(narrator) More recent study, though, has revealed a different shape
hidden in the dramatic object.
It turns out that modern observations have shown us
that the Helix Nebula actually has two intersecting rings.
(narrator) If we could fly around it,
the Eye of God is suddenly transformed
into something dramatically different.
About 3,000 planetary nebulas
like the Eye of God are known in our galaxy.
They come in a kaleidoscopic mix of strange shapes...
Each a different way a dying star
takes its final gasp.
(Filippenko) There's the Cat's Eye Nebula.
There's the Lemon Slice Nebula.
There's the Owl Nebula.
One of my favorites is the Eskimo Nebula,
because it really does look like there's a face there,
surrounded by a hood to keep it warm.
(narrator) Strange shapes also signal the deaths of stars
that end their lives not so gently
but in violent explosions.
About 7,000 light-years away,
odd-looking evidence of such a blast remains.
It was observed in X-rays,
and when we look at the structure of it,
it appears to have these sort of spooky, dark eyes
and then a grinning face, almost like a ghoulish pumpkin.
(narrator) Consider this a literal blast from the past,
marking a mystery more than 1,000 years old.
(Filippenko) In the year 1006,
a bright star was suddenly seen in the sky,
and it lasted for many months.
It was brighter than Venus. It could be seen during the day.
What could this possibly be?
We now know that this object is the remnant,
the expanding gases, of an exploding star,
a supernova.
(narrator) The most famous of the supernova remnants
is the Crab Nebula,
its shape reminiscent of a crab's shell.
Another is nicknamed the Hand of God
for the form its long fingers of glowing gas
appear to take.
About 300 supernova remnants are visible in some detail
to Earth telescopes,
each one with a different shape.
In supernova remnants, we see a variety of different shapes.
Some look like the "@" sign.
Some look like a Q, the letter Q.
Some look spherical.
There's even one that looks like a manatee.
I don't know how you get the manatee.
That's just crazy.
(narrator) How can the simple spherical shape of a star explode
to create such bizarre remnants?
To investigate, astronomer Andy Howell
enlisted the help of pyrotechnicians.
Well, a supernova, you know, starts with a star
that's spherical, and then
sometimes the explosions are spherical, sometimes not,
so it'll be interesting to see what we get here.
Sure. Okay, let's go over to the firing box,
- and we'll try one out. - Awesome.
Expecting to see, like, a plunger or something here, but--
[laughs] Like the old days.
- We ready to go? - Yeah.
All right, three, two, one.
Whoa-ho-ho!
Whoa, whoa. That one was--that looks cool.
Let's run that back and see it at the beginning.
It's exploding in some not completely spherical way,
and we see that in stars sometimes
when you light the star off center,
you can get an aspherical explosion.
And, wow, here we really see this plume of material
coming out, messing up the spherical symmetry,
and sometimes we see that in supernova remnants.
You'll see some little jet that sort of shot out
of the supernova.
So it's not exactly a supernova,
but it's pretty analogous.
(narrator) Some other stellar explosions,
as well as the planetary nebulas,
are often split personalities.
How can a star possibly start out as a sphere
and then shoot out in two clear directions?
We're trying to demonstrate how some shapes
we see in remnants are bipolar.
Explosions happen, not spherically,
but they come out to the side.
(narrator) A belt of dense debris
may surround an exploding star in space.
On Earth, a metal barrier between explosive charges
does the same job.
(Howell) Any time there's an obstruction, of course,
the energy is going to go where it has least resistance.
It's just going to shoot out.
Okay, so let's fire it, see what we get.
- All right, ready to go? - Ready to go.
All right, three, two, one.
[laughs] Whoa!
When we made an explosion with a barrier in the middle,
we get these beautiful lobes go out on either side.
We see that in a lot of astrophysical contexts
where you have a ring or a disc of material,
and it obstructs the explosion, or the mass lost from the star,
and you see stuff flying out in these lobes.
(narrator) Of all the bipolar shapes in the cosmos,
there's one that's attracting special attention.
The double cloud of glowing gas hides a giant star,
now thought to be an ultra powerful supernova
in the making.
What makes it so different?
And why do some think
it could wipe out millions of species on Earth?
(narrator) In searching space for its strangest shapes,
a certain spot near the Southern Cross constellation
stands out.
There, our ancestors were once perplexed by a sudden mystery
from an ancient star named Eta Carinae.
Eta Carinae is a star
that was relatively obscure for a long time,
but in the early 1840s, it brightened
to become the second brightest star in the sky.
(narrator) A century later, another layer of mystery
enveloped the strange star.
In the 1940s, telescopic observations of Eta Carinae
showed that it wasn't just a point-like star,
but rather, it had a nebula, a cloud of gas, around it.
And in fact, the shape reminded people of a little man
with stubby arms and feet and kind of a pointy head.
(narrator) The nebula was nicknamed the "Homunculus,"
for the humanlike creature alchemists were once said
to have created in their laboratory flasks.
Today's telescopes give us a very clear view
of the gas cloud.
What forces were at work to carve out this strange shape?
To explore the answer, astronomer Laura Danly
wants to bring the nebula down to Earth.
- Bryan. - Hey, Laura.
Nice to see you.
(narrator) Cutting-edge 3-D printing
will allow her to hold the Homunculus
in the palm of her hand.
It actually breaks it up,
layer by layer, into essentially the path
that's going to get traced out by the 3-D printer.
Wow, that's not too different from what the scientists did
when they observed it.
(narrator) In 2014, astronomers took about a hundred telescope slices
of the Homunculus,
essentially scanning it in 3-D.
Now the printer uses the data to deposit plastic filament
onto a platform,
where, over the span of eight hours,
the telescope slices take solid form.
It's amazing to be able to hold in my hand
the Homunculus Nebula.
I observed this myself as a grad student,
but to be able to look at it
and see things you can't see from Earth
is really an amazing thing.
For a long time, we thought that Eta Carinae
was just a single star,
so we now know that there is a binary pair.
What we didn't know is, did the binary pair
have any influence on the shape of this Homunculus Nebula?
Now with this 3-D model, we know that it did.
(narrator) Dimples and ridges on each end of the nebula,
plus two distinctive protrusions are the key clues.
Inside the nebula, the binary stars circle each other--
one 30 times the mass of the sun, the other 90.
Each one emits intense outflows of particles
called stellar winds.
The smaller star whips around the larger one,
carving a tunnel through its stellar winds,
leaving physical imprints on the nebula's cloud.
The story of Eta Carinae, however, is far from over.
In the future, we know that Eta Carinae
will actually undergo a final explosive death,
and at that point when it does explode,
it'll crash into these gases that it had previously ejected,
and this will cause it to become enormously more powerful
than just a typical, run-of-the-mill supernova.
(narrator) Some believe it may produce a gamma ray burst,
a deadly beam of radiation that could cause a mass extinction
here on Earth.
Most astronomers, however, say it's too far away
and the beam wouldn't be a direct hit,
so we're safe for now.
Humanlike shapes such as the odd Homunculus
are actually everywhere in the cosmos.
Could the universe be trying to get our attention?
When we look around us and see
these incredible shapes in nature,
we map them into things we're familiar with on Earth,
like a butterfly or a face or an eye,
and that's this phenomenon called pareidolia.
It just means our monkey brains evolved to recognize
things that would be of interest to us as people.
(narrator) Faces in particular jump out at us everywhere.
Like the ancients, we still see the man in the moon.
The sun recently had surface activity looking like a face,
and if you look carefully on Saturn's moon, Dione,
you'll see a face there too.
But Saturn itself is the epitome of strange shapes.
It's said that beauty is in the eye of the beholder,
but I know few people who don't think
that Saturn is beautiful.
(narrator) The ancients assumed the planet was a simple sphere,
but when Galileo first saw it through his telescope in 1610,
the fuzzy image opened up a new celestial mystery.
When Galileo originally observed Saturn,
he had really a rudimentary telescope
and not great eyesight.
So what he saw was a planetary body
or something that appeared to be a planetary body
with lobes off of the side of it,
and so he drew, in his notebook,
a planet that had these lobes and arcs
off of the side of the planet.
(narrator) As Saturn and the Earth each revolve around the sun,
Saturn's angle, as we look at it, is always changing.
For early telescopes, it was a challenge.
One of the additional difficulties would be
the fact that that fuzzy shape with the two ends
would actually be changing, and that's because, of course,
the rings are changing their tilt one way or the other
as we look at them.
When they're edge-on, they would actually almost disappear,
so it would've been very confusing
as to what could make that shape change.
(narrator) When astronomers concluded Saturn had rings,
the problem was solved,
but it took some 17th-century out-of-the-box thinking.
(Danly) It was really an amazing insight.
No one had ever seen or even thought about something like it.
They had seen planets through telescopes,
and they were all round, but to imagine a planet
with rings around it was really a leap of imagination.
(narrator) But the rings aren't the only strange shapes circling Saturn.
The planet is surrounded by a mysterious array
of weird objects,
among them 62 known moons.
(Howell) My favorite Saturn moon is Mimas
'cause it looks like the Death Star.
It looks just like the Death Star!
In fact, in Star Wars, they say,
"That's no moon. That's a space station."
And that's what it looks like,
but we know that the laser death ray on Mimas
is actually just a crater.
There was some giant impact in its past.
(narrator) But the most mysterious shape in the Saturn system
is on the ringed planet itself.
Centered on its pole is a bizarre shape
that seems impossible in nature.
Could it be a sign of intelligent life?
have mystified mankind for thousands of years.
While modern science can explain many of the phenomena
that baffled the ancients,
it has also uncovered new mysteries
that we're only beginning to understand.
The rings of Saturn once puzzled our ancestors.
But recent close-ups reveal a shape
that seems to defy explanation:
a hexagon at Saturn's north pole.
When I first saw these pictures of Saturn--
at one of the poles, there's this hexagon shape--
I thought, "How the hell do you get that?"
(narrator) The clouds making up the hexagon form six straight sides,
each 8,600 miles long.
Four planet Earths would fit inside of it.
How can nature create this seemingly impossible shape?
It's thought that the hexagon is formed
when winds of differing speeds next to each other
are actually creating vortices or rotations in the atmosphere.
(narrator) But rotations in an atmosphere speed up to become storms.
It happens that way on Earth,
where swirling storms produce hurricanes or tornados,
all more or less circular in shape.
The same is true for the other gas giants in the solar system.
How can something round
end up creating something with six straight sides?
This laboratory simulation in a tank of rotating fluids
may reveal the secret.
Six swirling vortexes around the edge
work together to create the familiar shape.
The vortexes on the ringed planet
are thought to be atmospheric cyclones,
large storms the size of Earth that are not visible from space.
Most of the action is apparently below the surface.
The very sharp corners of the hexagon
are the places where there are pinch points
between two cyclones,
so it looks like it's kind of an unnatural shape in nature,
but in fact, it's very naturally shaped by those storms.
(narrator) The extreme winds and chemical clouds of the gas giants
create strange shapes in a realm of wild, fluid motions.
But on the rocky planets of the inner solar system,
other forces are at work.
The planet Mars is especially rich
in weirdly shaped rocks and landscapes.
(Howell) We see a lot of strange shapes on Mars,
because now we have so many satellites and robots on Mars
that we're seeing so much of the planet.
There's just a lot more chance to see cool stuff.
(narrator) The mysteries of Mars began in ancient times.
Its red color led the Chinese to call it "the fire star"
and the Romans to name it for their god of war.
19th-century astronomers thought they saw canals
built by aliens on a Mars rich with vegetation.
[dramatic music]
♪ ♪
The notion of a powerful Martian civilization
lasted well into modern times,
when space probes revealed the truth.
From our spacecraft that we have observing Mars today,
we know that Mars is not a rich, lush environment
that has life and plants on it.
From the photos from Mars,
there are just a host of strange shapes that we can see,
either from orbit or from the surface.
Things like smiley faces in craters,
the man on Mars,
footprint-shaped craters, heart-shaped craters,
and on the surface, we see rocks that look like rodents,
frogs, blueberries, bones, traffic lights--
just a whole host of different things that we can see.
(narrator) And those shapes can change.
In 1976, a Mars orbiter
saw the infamous face on Mars,
but in 2001, a more advanced orbiter saw the same feature.
With different lighting and higher resolution,
the face virtually disappears.
Nevertheless, we have an innate human tendency
to see familiar forms in all kinds of objects,
even here on Earth.
At the top of this crest right here,
I see what looks like a toad or a frog.
And if we turn behind us and tilt our heads slightly,
we can see the facial features of something
that looks almost like a troll or a goblin,
so it really demonstrates how you can take
very unfamiliar-looking terrain
and find features in it that look very familiar to us.
(narrator) The shapes on Mars teach us
about the environment that formed them.
Today, Mars is a very dry, windy place,
and so the only forces that are really acting upon rocks
today on Mars are the wind and impacts.
Earlier in Mars' history, if Mars was a much wetter place
than it is today, water would have also contributed
to the shape and appearance of the rocks on the surface.
(narrator) Wind and weather may explain
how the rocks of Mars take on so many different shapes,
but what explains the even more bizarre shapes
hurtling towards us through the far reaches of space?
Among the glistening stars fixed permanently in ancient skies,
an occasional misbehaving intruder would strike fear
into the hearts of the earliest astronomers.
Today we call them comets,
from the Greek word for "long hair,"
an allusion to their glowing tails.
To our ancestors, they were invariably bad news.
(Danly) Comets were terrifying to our ancestors.
They didn't know what they were.
They didn't know where they came from.
They just appeared, and they were unlike anything
they had ever seen before.
(narrator) Records of comet sightings
go back at least as far as 1600 B.C. in China,
where they were known as "vile stars."
Other cultures blamed them for various calamities:
the murder of Julius Caesar in Rome,
the Black Death in England,
the arrival of the conquistadors in South America.
Modern science tells us comets are dirty snowballs,
collections of ice and dust,
left over from the solar system's formation.
[dramatic music]
The sun heats them up,
and jets of matter stream out to form their spectacular tails.
But the closer you look, the stranger comets become.
(Danly) Even through a telescope, we didn't really know
what the true shape of a comet was,
until we were able to send spacecraft out to visit them
and look up close.
(narrator) The spacecraft Giotto made the first flyby in 1985,
revealing a close-up of Halley's Comet.
It proved that comets are lumpy objects
in the strangest of shapes.
And now that we've gotten up-close views,
we see that they don't look anything like we thought.
There are a handful of them that are sort of roundish,
but the majority of those we've seen
have a double-lobed shape.
(narrator) In 2004, the Rosetta mission was launched
on a ten-year journey to orbit and place a lander
on a comet more than 300 million miles from Earth.
Prior to the launch, the Hubble space telescopes
snapped 61 grainy photos of the comet.
By analyzing tiny fluctuations in its brightness,
astronomers calculated its approximate form--
an irregular lump, tumbling through space
at two revolutions per day.
But in late 2014, the probe finally approached the comet,
and scientists were shocked at the bizarre shape they saw.
The very recent Rosetta mission
took exquisite photographs of Comet 67P,
showing that it actually resembles a rubber ducky.
It would have been awesome if it was a real rubber ducky,
but it's just a bunch of rocks that look like a rubber ducky.
(Walkowicz) The thing is, we don't really know
how you make a comet that is this shape.
It's extremely complicated,
and we didn't really expect to see something
that was that shape to begin with.
There are a couple of different ways in which comets
could get that double-lobed shape.
One is, indeed, two objects that sort of stick together
that, when they collide, they don't collide with enough force
to bounce off each other or shatter each other
but just to sort of stick to one another.
(narrator) But could Comet 67P have formed as a single object,
getting its curious shape later on?
Now, you could also imagine that the cometary physics is at work
in sculpting this particular odd shape.
As the comet comes into our inner solar system,
gases start to stream off from it as it gets heated up
by the light from our sun.
You can think of these a little bit
as though they were like geysers on our planet,
geologic activity where warmer material
starts to stream out of the comet,
possibly causing cracking and reshaping of the surface.
(narrator) Could Rosetta's up-close view tell us which of the scenarios
is the right one?
(Danly) Recent observations show that the composition
of the two lobes of 67P are very similar.
That suggests they came from the same body.
We also see that most of the outgassing
comes right at the neck of the rubber ducky,
right at the thinnest part,
so it wears it away and leaves two big lobes on either end.
(narrator) Comets are the lightweights in nearby space.
The asteroids and dwarf planets are their big cousins,
heavier, denser, and in many respects, stranger.
What forces mold these planetary mavericks,
and why, in their midst, is there a place in space
where X marks the spot?
A giant impact may killed off the dinosaurs
about 65 million years ago.
And ancient mythology is filled
with legends of rocks from the sky.
The Greek deity Kronos is said to have cast a meteor to Earth
landing at Delphi, where it was worshipped as sacred.
This brings the search for strange shapes in the universe
to the space between Mars and Jupiter,
where the oddly formed asteroids are found.
Most meteorites come from the asteroid belt.
They're little chunks of asteroid that,
through collisions, got knocked off their orbits
and fell to Earth.
[dramatic music]
♪ ♪
(narrator) Austria, 1492.
The 250-pound Thunderstone of Ensisheim
falls in a fiery streak.
A thunderclap is heard for hundreds of miles around.
[thunder]
(Danly) Like comets, meteorites were bad news.
Emperor Maximilian was so worried about the meteorite,
he had it chained to the church floor
because only by securing it to holy ground
could he neutralize the evil influence.
(narrator) Mysteries among these space rocks persist today.
An eerily ominous shape appeared in the asteroid belt in 2010.
Why did an X suddenly appear there,
with a trail of debris lagging behind it?
Here we have a very unusual asteroid that has a tail
and looks like a comet, but further observation showed
that it has no gas in the tail like a comet would.
Instead, the tail is made of dust.
(narrator) Scientists believe the mysterious debris tail
resulted from a small asteroid striking a much larger one,
but why the cloud of dust in the shape of an X?
One possible explanation for the X shape
is that it's caused by a collision.
The two asteroids were not symmetrical,
and so the crash is not symmetrical.
Imagine a pool of water.
If you drop a single drop into it,
you get perfectly round, smooth ripples,
but if you drop something else,
like ice cubes with square edges,
you'll get a ragged splash,
kind of like the ragged X in the asteroid crash.
(narrator) Collisions help make the asteroid belt
an astronomical sideshow
made up of a fantastic variety of misshapen freaks.
Asteroid Eros may look like a ballet slipper to some,
but other asteroids are grotesque figures
that defy description.
The lumpy, irregular shapes of asteroids
are basically pretty random.
There's no favored shape.
(narrator) In fact, irregular shapes
are found throughout the solar system.
But why are some moons or asteroids round
while others are such bizarre lumps?
(Johnson) The largest objects in our solar system,
and even some very large asteroids,
can have their shape be dominated mostly
by gravitational forces
pulling things into a spherical shape.
(narrator) In the solar system,
everything above about 400 miles in diameter is spherical,
because at that size,
gravity is strong enough to crush rock.
It presses from all sides toward the center.
It's something like someone's hands
pressing on a lump of snow to make a spherical snowball.
♪ ♪
Gravity has done its work on Ceres,
the most massive object in the asteroid belt.
The Dawn spacecraft began orbiting the asteroid
in March 2015,
revealing it to be fully spherical in shape.
Because its shape is dominated by gravity,
it conforms to the definition of a dwarf planet.
Pluto and other dwarf planets in the outer solar system
follow the same rule and are also spherical in shape.
The one exception to this in our solar system
is the dwarf planet Haumea,
which has a very elongated shape.
Haumea lies out beyond the orbit of Pluto
and is actually spinning so rapidly
that the centrifugal forces that it experiences
are enough to stretch Haumea to a much more elongated shape.
(narrator) But beyond Haumea, beyond the solar system,
beyond the galaxy, the search for strange shapes
extends into the depths of space.
There, the ancients viewed a fuzzy patch among the stars
of the constellation Andromeda.
They were perplexed by what it was,
scarcely knowing it would one day
help solve a fundamental mystery
to reveal the ultimate true size of the universe.
darkness reigns.
Polar bears are common here.
So, too, are elk
and other dangerous creatures
that serve as both predator and prey
for the hearty few who make this land their home.
It is dark and scary
and potentially deadly.
Suddenly, a man out hunting sees it,
a threat known to his people since ancient times.
So he does what comes naturally,
what generations of native Alaskans have done before him.
He draws his weapon
and prepares to defend himself
from the swirling electrical madness
he sees in the skies.
Blazing lights.
A mysterious and ever-changing symphony of color.
Today, we know this phenomenon as the aurora borealis,
the Northern Lights.
And for many cultures, like the Eskimos
living near Barrow, Alaska,
the aurora is a bad omen.
Auroras, the northern or southern lights,
have often been seen as bad omens because
there are these ghostly lights in the sky
and they're flickering and they're of unknown origin
to the people watching them.
Are the gods angry or something?
(narrator) So what causes this sparkling show in the sky?
Aurorae are fascinating examples
of the interaction between
the sun and us here on Earth.
(Walkowicz) The sun has what we call space weather.
These are solar flares or other phenomena associated with
the sun's magnetic activity
that shower our planet with not only high energy radiation
but also energetic particles.
Earth has a magnetic field.
Now, if that magnetic field was in isolation,
it would look sort of like a cored apple.
But it's not in isolation.
The solar wind charged particles streaming out of the sun
impinges upon Earth,
flattening the nearside and extending the farside
of that field.
It also has holes at
the north and the south
called polar cusps.
Solar wind can flow into the polar cusps,
creating the aurora borealis
and the aurora australis.
As they excite the gases in our atmosphere,
depending upon the gases that get excited,
you get different colors.
These different gases are exactly what are used to make
the neon signs that we see down at the deli.
When you see that green palm tree or that red open sign,
those are different gases being energized
and it's the light escaping
as the electrons change energy levels
that we perceive as these different colors.
(narrator) The spectacular light show an aurora provides
isn't the only way to experience one.
As it turns out, you can actually hear an aurora too.
There have always been stories of people hearing sounds
associated with the aurora.
Popping and whistling noises.
But it was unclear if these were just stories
or real, until recently
when scientists were finally able to record
that, under very certain circumstances,
you can hear whistling and popping noises
associated with the sun's energy interacting with
our own Earth's atmosphere.
(narrator) What causes the sound is still a bit of a mystery.
Researchers think the same solar energy waves
that generate the spectacular lights in the sky
are also responsible for the sounds closer to the ground.
The phenomenon of auroras is an ancient mystery
that stretches across the cosmos.
(Gay) Jupiter has amazing aurorae that we see on a regular basis.
Saturn has aurorae.
And even Venus.
(narrator) Omens, portents, and signs
are how ancient people made sense of their universe.
Today, astronomers are making remarkable discoveries
that help explain the science behind
these once terrifying events.
One of the things that's really amazing about
the time that we live in, is that all of these things
that were very scary for our ancestors
we now understand through the lens of science.
(Markley) Humans always want to know about the future.
Whether you're an ancient Roman, an ancient Chinese,
a person living in America in the 21st century,
we want to look for signs in nature, signs in the heavens,
that can help us understand things,
can reassure us that we know
what will happen in the future.
As we learn more about the universe,
knowledge is replacing fear.
People go north to see the aurora.
They take eclipse cruises.
Yesterday's bad omens are today's tourist attractions.
(narrator) This, then, is humanity at the dawn of the 21st century,
striving to understand and experience first hand
what men and women through the millennia
formerly saw as bad omens.