(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<i> Star Wars</i> 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 outt 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<i> Star Wars,</i> 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? (narrator)
Strange shapes and patterns
in the heavens 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. [futuristic music] ♪ ♪ In fact, Mars is the only planet
we know about that's entirely populated
by robots. Of course,
it's robots that we sent there. (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)
Photos from Mars are posted
online every day, and amateur observers have
an Internet obsession, combing through them to pick out
weird objects. Could these be evidence
of intelligence, as some of these amateurs
believe, or is nature just teasing us? Well, there's millions of rocks
on the surface of Mars in various configurations. In a chaotic system with
so many different variations, nearly any conceivable shape
will be visible somewhere at some point in time. (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? (narrator)
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<i> Giotto </i>
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<i> Rosetta</i> 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<i> Rosetta</i> 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<i> Rosetta's</i> 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? (narrator)
Planet Earth has always been
a target for impacts from space. 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<i> Dawn</i> 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. [indistinct chatter] (narrator)
More an a thousand years ago, stargazers identified
something strange among the stars
of the constellation Andromeda. Neither a star, a planet,
nor a comet, it was an indistinct smudge and a mystery unsolved
for centuries. My favorite strange shape
in the sky is the Andromeda Nebula. That's what people
used to call it, 'cause they just saw
this smudge, and they used the word
for "cloud," "nebula." (narrator)
Stranger still, the first telescopic photo
in 1888 showed its oval form
with spiral arms. No one realized that
the intriguing Andromeda Nebula would upend humanity's view
of the universe. Initially, the entire universe was thought to consist
of our galaxy. All the stars in our galaxy,
all the stars we see in the sky, everybody thought,
"Well, that's just it." One of the puzzles about what were called nebulae
at the time was, exactly what they were
and where were they? How far away were they? (narrator)
Was the Andromeda Nebula
relatively near or impossibly far? The key clue came in 1908, from Henrietta Leavitt,
one in a team of women paid 25¢ an hour
at Harvard Observatory to analyze telescope photographs
on glass plates. Henrietta Leavitt had spent
a lot of time studying particular types
of variable stars, how those stars changed
their brightness. (narrator)
These so-called variable stars expand and contract
in a regular cycle, almost as if they are breathing,
getting brighter and dimmer, brighter and dimmer. Leavitt discovered that
you can tell how bright certain types
of variable stars are by how fast they're pulsing. The slower the pulse, the greater
their overall brightness. If two variable stars
are pulsing with the same cycle, we know that they have
the same overall brightness. Now take one of them
and move it far away. It looks dimmer to our eye,
but by counting the pulses, we know it's as bright
as the near star. So we can use that difference
in apparent brightness to calculate how far away it is. (narrator)
Legendary astronomer
Edwin Hubble then took up the detective work. On October 5, 1923, he examined
the Andromeda Nebula and detected a variable star that has been called "the star
that changed the universe." Counting the pulses,
he figured its distance, which is now known to be
2.5 million light-years away. The distance seemed
impossibly large, so large, in fact, that it led
to only one conclusion. It turns out
that the Andromeda Nebula is a galaxy full of stars. It's another galaxy that's even
bigger than our own galaxy. (narrator)
In fact, the mysterious
little cloud of the ancients was not alone. Telescopes revealed others
like it, each of which was also a galaxy. The universe had
billions of them. When we learned that Andromeda
was outside our galaxy, it was a revolution
in our understanding in our place in the universe, so this strangely shaped nebula
that no one knew what it was really held the key to unlocking
a universe of galaxies. (narrator)
Today, astronomers marvel
at the number of galaxies observed in the cosmos. Some of their strangest shapes
are caused when two galaxies
come close together and are twisted or distorted
by gravity. In some cases, they end up
looking very peculiar, like there's the Tadpole Galaxy that has a galaxy
with a long tail, looks like a pollywog. There are the Mice, two galaxies
with two tails sticking out. There's the Antennae Galaxy, again, two galaxies
with two antennae sticking out. (narrator)
We live in a universe full of strangely shaped
galaxies, each populated by
strangely shaped asteroids, comets, and nebulas, and full of planets covered
with strangely shaped rocks. From our ancient ancestors
seeing a face on the moon to modern scientists spotting
a giant hexagon on Jupiter, the heavens have concealed
mysteries across time and at every scale. Maybe the most grand structure
in the universe is this filamentary
web structure that connects
all the galaxies together. It's like the scaffolding
of the universe, maybe the skeleton
of the universe. (narrator)
The latest version
of the cosmic skeleton is generated
by the Illustris Project, a massive supercomputer
simulation. Like the diagrams and models
of the celestial sphere created by our ancestors, it essentially encompasses
the entire visible universe. Breathtaking in scope, it displays the structure
of the cosmos in minute detail. It is a big-picture view of
literally everything we can see, and in a universe
of strange shapes, it is surely the strangest shape
of them all.
