(dramatic music) - [Narrator] It lords
over the solar system. A mega-world two and
a half times the mass of all the other
planets combined. This spinning giant whips
up hazardous radiation, ferocious hurricanes, and treacherous magnetic fields. A spacecraft charges
into the maelstrom daring the planet Jupiter
to give up its secrets. Juno is part of a larger effort
to see into giant Jupiter, to glimpse a time over
four billion years ago when planets were
born and obliterated. Flung into space or
tossed into the sun. It was a time when the
fate of our own small and fragile world
hung in the balance. (light dramatic music) The Greeks called him
Zeus, the Romans, Jupiter. The king of the gods hid
his nefarious activities behind swirling clouds. Only his wife, the goddess
Juno, could pierce the veil of mists to catch
him in the act. NASA's Juno, the Jupiter
near-polar orbiter, left Earth on a
mission to peer into the mysterious
Jovian atmosphere. To find clues to
the powerful forces that ch
urn beneath its
roiling cloud tops. And some of 300,000
times the mass of Earth, Jupiter holds over
70% of the mass of the solar system
beyond the sun. Juno is the latest in
a series of missions designed to measure the
properties of the planet, how it got so large, and how it shaped
a rocky blue world. Earth. (light funky music) To understand
Jupiter's early years, astronomers have been watching another solar system take shape. Out in the constellation Pictor, 63.4 light years away, a
young star
, Beta Pictoris, is growing its first
crop of planets. One is large enough
and far enough from the star to be photographed. Beta Pictoris B. Astronomers have now seen it
on both sides of its orbit. Look at Beta Pic and
you'll see a snapshot of our solar system more
than four billion years ago. The observed planet is
growing within the outer zone. Only clouds of
dust and gas, ice, and countless small objects
called planetesimals. With matter swirling into it, the planet is likely a
fury of gravit
ational and magnetic energy. Likewise, its distant
cousin, Jupiter, is surrounded by a raging
but invisible maelstrom. The king planet's magnetic field is 20,000 times stronger
than that of Earth. Looking up from Earth, if
you could see Jupiter's magnetosphere in the night's sky it would appear wider
than the full moon. Jupiter's zone of magnetic
influence is so large that it flares out beyond
the orbit of Saturn like a lightning bolt hurled by Zeus
into the outer solar system. Jupiter's magneti
c
field is the product of a powerful double dynamo. One is down deep and
permeates the planet, the other close to the
surface, rings the Equator. When Jupiter's moon, Io, moves
through this magnetic field, it emits powerful
bursts of radio energy strong enough to be
detected on Earth. Volcanic eruptions
on Io send a flood of charged particles
into this field. They, in turn, energize
massive auroras that light up the poles
on this giant world. A haze of charged particles
races around the planet f
orming a belt of
radiation 1,000 times the lethal dose for humans. Flying by in 1973, Pioneer
10 provided the first hints of this radiation
belt when it passed within 130,000 kilometers
of Jupiter's cloud tops. A year later, Pioneer 11
took the first closeups of the great red spot, Jupiter's
immense signature storm. The Pioneer findings
informed the design of the Twin Voyager spacecraft. Launched in 1977, engineers
shielded critical voyager components from radiation. That allowed the
Voyager cra
ft to capture some 19,000 images
including new views of Jupiter's ghostly rings. The startling icy
terrain of its big moons Europa and Ganymede and
powerful active volcanoes on its inner moon, Io. The Galileo Mission got
even closer in 1995. Galileo sent back a treasure
trove of discoveries about Jupiter's atmosphere. With a composition nearly
identical to the sun, Jupiter offers a
window into the birth of our solar system some
five billion years ago. (intense dramatic music) Stars and planets
a
re born when clouds of gas and dust contract, often quickened by the
explosion of a nearby star. A shockwave from the
dying star causes the cloud to
collapse and to spin. As matter flows into its center, temperatures rise high enough
to create a dim proto star. Within the disc, billions
of tiny dust particles collide and stick
together forming sand-like rings called chondrules. Attracted to one
another by gravity and static electricity,
chondrules join to form pebbles. Pebbles become boulders. A
nd finally, planetesimals. These kilometer-scale
objects can collide, sticking together
or breaking apart. Meanwhile, matter continues
to flow into the central star. As the star brightens, winds
of radiation begin to blur, pushing the remaining
dust and gas outward. At some distance out,
called the ice line, temperatures in the
nebula are low enough for water, methane, ammonia
and carbon compounds to form solid crystals. Out here, objects made of rock and ice come together quickly
to form proto
planets. By this process, the
largest grow the fastest. To withstand Jupiter's
punishing radiation, Juno's electronic circuits were
encased in a titanium volt. Its components were built of
radiation-hardened material. Every part of Juno that can
be, is wrapped in lead foil. Launched on August
the fifth, 2011, Juno is formally known as the
Jupiter Near Polar Explorer. It was the second launch of
NASA's New Frontiers Program. This series of
medium-sized missions is designed to expand our
knowledge
of planetary bodies and deliver new insights into the origins of the solar system. (light music) The first mission,
called New Horizons, traveled nine and a half years
to the outer solar system. It mapped the surfaces of
Pluto and its moon Charon, collected information
on their geology and found clues to their
complex and violent history. The third mission,
called Osiris Rex, was sent out in 2016 to an
asteroid called 101955 Bennu. The idea was to actually
land on the asteroid, pick up rocks an
d
return them to Earth. These samples will help
address basic questions, not only about the birth
of the solar system, but the origin of
organic molecules that helped spark the
evolution of life on Earth. To score important new science, these missions have each taken on daunting
technical challenges. For Juno, the challenge
is to fly close to Jupiter without getting fried by its
powerful radiation belts. To do this, the
spacecraft was sent into a series of highly
elliptical orbits to track acros
s Jupiter's poles. Then to dive beneath
its radiation belts and pass within 4,100 kilometers
of Jupiter's cloud tops. Out of each 53-day orbit, Jupiter spends just two hours
in the zone of maximum danger. The craft spins three
times each minute, allowing its
instruments to capture about 400 slices of
data from pole to pole. Besides photographing its
complex surface features, Juno is performing a
cat scan of Jupiter. When scientists
look at the planet, they see structures like
those in Earth's at
mosphere. Cyclones, anticyclones, jet streams, storms
pushing upward. And yet Jupiter and
its weather systems are radically different. For one thing, the
planet is much larger. It also rotates faster
and sits much farther from the sun's
warming radiation. The intricate structures
scrolling across the cloud tops are a window to
conditions deep inside it. Juno's data shows that
Jupiter's surface flows extend down as deep
as 3,000 kilometers. Below that, magnetic
fields slow them way down and pull
the planet
into a uniform rotation. Deeper still, scientists
suspect the inner zone is a sphere of metallic hydrogen surrounding a solid
core of rock and ice. Throughout most of
the 20th century, scientists theorized that
giant planets like Jupiter form in long orbits
far from their stars. While these planets
grow by scooping up a rich supply of
icy planetesimals. Planets inside the
ice line stay small because there is less solid food during their formative years. This general understanding
was
blown away by recent exoplanet discoveries. The Kepler Space Missions,
along with ground-based planet-hunting systems, have
identified more than 2,000 stars with orbiting worlds. So far, few resemble
our solar system. The inner orbits of
many star systems are graced with
so-called hot Jupiters, large gas giants the
size of Jupiter or larger that whip around their
parent stars at close range. Some are being stripped of
gas by powerful solar winds. Then, there's a class
of rocky super Earths. At a
bout twice the mass
of our home planet, they occupy the innermost orbits of many other solar systems. It turns out that the
most common planets within these inner regions
are not rocky at all. It's a class of gas dwarves
smaller than our Neptune that weigh up to
about 10 Earth masses. Smaller, Earth-sized
planets, are in fact rare. How did our solar system evolve in such a different direction? The answer may lie in
Jupiter's turbulent past. As Juno passes in
close to the planet her path bends in
response to concentrations of mass beneath its surface. Because Jupiter isn't solid, those regions are free
to move and shift. Jupiter spins faster
than any other planet in the solar
system, turning once every nine hours and 55 minutes. That bulges is its equator
route and flattens its poles. By plotting tiny variations
in Juno's timing as it orbits, investigators can
detect concentrations of mass below the surface. What Jupiter is made of,
how its density varies, how forcefully it now spins, a
nd how massive or
solid is its core. These are all clues as to
when and how it formed. Our solar system
is still buzzing with the remnants of its birth. Wandering rocks
that haven't changed since they formed almost
five billion years ago. Most are so small that
when they encounter Earth they simply burn up
in the atmosphere. A few larger ones
survive the fall. Scientists date these
planetary shards by measuring molecular
variations, called isotopes, of two particular metals. Tungsten and molybde
num. These meteorites
appear to come from two separate
populations that formed in the inner and the
outer solar system. Something must have
driven a wedge between these two regions
preventing them from mixing. If this great divider
was the young Jupiter it had to of grown very fast. Reaching about 20
times the mass of Earth within the first million
years of the Sun's formation. Its gas giant neighbors,
Saturn, Uranus and Neptune, would've formed in its wake. By dividing the solar
system in this
way, Jupiter would've cut
off the flow of matter into the inner solar system,
stalling the formation of large rocky planets
or super Earths. Then came one of the
most impactful events in the history of
our solar system. One set in motion by
Jupiter's sensational rise. (light dramatic music) The discovery of
large gas planets within the inner regions
of other solar systems has prompted a whole
new set of questions. If these giant
planets formed beyond the ice line then
migrated inward, could Jupi
ter have
followed a similar path? To test this idea, scientists
used a super computer to reproduce the early
evolution of our solar system. They plant a set of
initial conditions into a program
designed to simulate the interaction of gas and
dust, gravity and energy. The simulation takes us into
one cold and dusty corner of the galaxy five
billion years ago. Shock waves from a supernova
explosion perturbed the cloud causing it to collapse into
a dense central region. Near its center is a
vast ro
tating hurricane of dust, gas and water. In its eye, matter flows into a newborn star
along a thin disc. Flashes of light within
the disc represent collisions among larger objects. Concentric rings
show their orbits. The large orbit on the
periphery is Jupiter, the first full-sized
planet to form. From its position
far from the sun, it has scooped up huge amounts
of ice and hydrogen gas. Within a million
years of its birth, Jupiter responds to
the gravity of the sun and the mass of the
inner sol
ar system. The model shows
Jupiter's inward spiral known as the Grand Tack. As the giant planet's
orbit shrinks, it sends the inner
solar system into chaos. Jupiter flings most large
objects into looping orbits around the outer solar system
while streaming into the sun. Finally, Jupiter feels the
pull of another growing planet. Saturn. And retreats to the
outer solar system. Jupiter gradually settled back
into its current position. That left some 20 or 30
small planetary embryos to patrol the
in
ner solar system. Here, the simulation
speeds up to cover the next 50 million years. As these embryos
tug on one another, their orbits destabilize. When the dust finally settles, perhaps a hundred
million years later, the number of planets
is down to five. Including Earth and a
Mars-sized world, Theia. Everything changed when Earth
and Theia crossed paths. (suspenseful music) A computer model gives us a
view of the first 24 hours. Theia sheers about a
third of Earth away. Its shattered remains
e
nvelope Earth in a shockwave of
superheated vaporized rock. A molten ring forms
around the planet, subjecting Earth to a
rain of secondary impacts. Within only a century,
this orbiting ring will cool and coalesce into
a single orbiting body. The moon. The violence of the moon's
formation would've left Earth spinning rapidly on a
slightly tilted axis. A day lasted only
about five hours. In time, the moon stabilized
the planet's tilt, holding it steady. As it moved out to its
current distance from
Earth, it gradually slowed
our planet's spin. If the Grand Tack theory
explains the evolution of the inner solar system,
then it may explain a host of details that've
long puzzled scientists. Why, for example,
is Mars so small? The idea is that
Jupiter swept up much of the dust that accumulated
just inside the ice line, starving Mars. What explains differences
among the various classes of asteroids? The asteroid Bennu, at roughly
500 meters in diameter, appears to be a fossil
from the time Jupi
ter sailed toward the sun. This dark object is made up
of carbon rich clay materials born in the explosion
of dying stars. Bennu itself is a
product of collisions. In its four billion
years of travel, the asteroid has
likely been stretched, pulled apart and reformed. To trace the asteroid's origins, scientists have launched
the Osiris Rex Mission with the goal of returning a
sample to labs back on Earth. They plan to send another
mission called Lucy to an ensemble of asteroids
that trails Jupite
r. These so-called trojan asteroids take their name from
soldiers who hid inside the giant horse
in Homer's Iliad. The thinking is that Jupiter
began pulling them along within the first million
years of its history. (light music) Then, there's the
main asteroid belt. A vast hoop of rocks
between Mars and Jupiter. Scientists believed that as
Jupiter moved toward the sun during the Grand
Tack it dispersed an original ring
of rocks and dust. When Jupiter moved back out, it drew a whole new
collecti
on of rocks back in. By studying the composition
of these asteroids, including a dwarf
planet called Ceres, scientists hope to
confirm their origin. (blasting) Finally, the giant planet
carries its own artifacts from the early solar system. Most of its 79 moons
are asteroids or comets captured over the
years when they flew too close to the giant planet. The four largest
satellites are different. If Io, Europa, Ganymede or
Calisto orbited the sun, we'd call them dwarf planets. Scientists believe
these moons form slowly from a disc of ice and debris that circled Jupiter very
late in its formation. All four are in tidal mark. Like our own moon, each keeps
the same face toward Jupiter. Io, the volcano moon,
orbits closest to Jupiter. Io shows what can come
from living too close to an unsympathetic god. Heaved and stretched by
gravitational interactions with Jupiter, and warped
by tidal resonances with the other
three large moons, Io is constantly being
turned inside out. With hundreds of v
olcanoes,
some blasting lava to altitudes up
to 400 kilometers, Io is the most geologically
active body in the solar system. Next is Europa with its bright, young, glossy surface
covered in ice. Ganymede, with a diameter
of 5,268 kilometers, is the largest moon
in the solar system. Larger even than
the planet Mercury. Then, there's Calisto. Two million kilometers
from Jupiter. Spacecraft sensors have shown
that these three icy moons; Europa, Calisto and Ganymede, hold different amounts of
water
beneath their surfaces. In Jupiter's early
years, ice, dust and gas flowed into the
planet along a disc. The Grand Tack model
predicts that Jupiter's disc would've shrunk as the
planet moved toward the sun. The two larger ice
moons must've started forming before that. Europa formed later and had
less water around it to attract. And Io had almost none. Jupiter's major
moons didn't hoard all of the planet's icy bounty. On its inward journey,
Jupiter would've carried a wave of ice in its wake. Deli
vering water
that might, one day, have filled Earth's oceans. Once settled back in
the outer solar system, Jupiter, along with
Saturn, began to hurl still more icy material to
the inner solar system. (dramatic instrumental music) Shards of rock and
ice rain down on Mars, Earth, Venus,
Mercury and the moon. The lunar landscape today
bears witness to this period. A 300 million year
fusillade known as the Late Heavy Bombardment. Based on data from the moon, scientists estimate that
our planet would
've been hit by at least four objects
5,000 kilometers across. Each capable of turning Earth's entire surface to molten lava. These collisions may
have unleashed a process critical to the emergence of
life called impact erosion. The impacts blasted
hot radioactive metals like uranium and
potassium off the planet. That allowed the
planet's outer crust to rapidly cool and
water to remain. Scientists believed that Earth was a water planet
in its early years. (dramatic music) Zipping along at 200,00
0
kilometers per hour, the Juno spacecraft
takes two hours to pass from pole to pole. In that time, it records
a variety of readings of a world that remains a
gargantuan work in progress. Winds up to 650
kilometers per hour whip cold clouds of methane,
hydrogen sulfide, water, and other compounds into
endlessly swirling works of art. Sometimes white
clouds of ammonia snow fly over the wide
southern red band making it seem to disappear
from Earth's point of view. It's cold in the clouds, about
mi
nus 125 degrees celsius. Deep within the atmosphere,
showers of compressed carbon may form between the
layers in a diamond rain. White spots mark the
crests of enormous waves rising and falling
along the surface. Twirling storms explode
into the upper atmosphere propelled by heating
hundreds of kilometers below. They unleash lightning
bolts far larger and stronger than
any scene on Earth. It's the polar regions
photographed for the first time ever by Juno
that have defied expectations. Here, the
belts and zones
of the middle latitudes disappear and the
atmosphere is dominated by an ensemble of hurricanes. During it's fourth
pass over the planet, Juno's infrared
imaging instrument captured these structures
in three dimensions. The northern pole
hosts a giant cyclone surrounded by
eight smaller ones, each over 4,000 kilometers wide. The bright yellow colors
show deeper warmer areas. The darker red colors
are cooler cloud tops. They lightly arise
from the interaction of smooth horizontal
flows and low latitudes and turbulence at the poles. The spin of the planet causes
them to drift poleward. This raw sequence gives a sense
of their spinning movements. By contrast, the
southern cyclone is surrounded by five cyclones. From on Earth's perspective, even these smaller
ones are vast. Up to 7,000
kilometers in diameter or about the width of Mars. Why these structures persist
without merging is not known. (light piano music) If there's a single
feature on Jupiter that has held us in it
s thrall,
it's the Great Red Spot. Juno has been flying
directly over it at an altitude of
9,000 kilometers. Close enough to
see fine details. Historical records show
this huge high pressure zone is at least 350 years old. Astronomers have been
measuring it since 1830. At about 16,500
kilometers across, it's 10 times larger than
Earth's largest typhoons. Juno's data suggests
the Great Red Spot heats the planet's
upper atmosphere. The big cyclone rotates
counterclockwise once every six Earth days
. That period has been getting
shorter as the storm tightens. The color sometimes fades
for years, then intensifies. No one knows why. (light music) It was the bright
light of Jupiter that attracted Galileo
Galilei in January of 1610. His small telescope
was powerful enough to resolve the four large
moons circling the great orb. If another world could have
satellites, he reasoned, it seemed possible that Earth could be a satellite of the sun. If only we could go back
in time to show Galileo clos
e ups of Jupiter
captured by Juno. How amazed he'd be to learn
that such giant planets are common in solar systems
throughout the galaxy. That billions of
years ago it marauded through our own
infant solar system. Destroying worlds, setting
the stage for new ones. What would he say of
our news that Jupiter left in its wake a quiet zone? Where a world with oceans
on its surface would form, and over time,
give rise to life. (light piano music)
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