They are part of an ancient quest. To push beyond our boundaries, to see what
lies beyond the horizon. Now tens of billions of kilometers from Earth,
two spacecraft are streaking out into the void. What will we learn about the Galaxy, the Universe,
and ourselves from Voyager’s epic Journey to the stars? December 19, 1972. The splashdown of the Apollo 17 crew capsule
marked the end of the golden age of manned spaceflight. The Mercury, Gemini, and Apollo programs had
proven that we could send people into space, to orbit the Earth, fly out beyond our planet,
then land on the moon and walk among its ancient craters. The collective will to send people beyond
our planet faded in times of economic uncertainty, war, and shifting priorities. And yet, just five years after Apollo ended,
scientists launched a new vision that was just as profound and even more far-reaching. We knew we were on a journey of discovery
when we launched the Voyager spacecraft, but we had no idea how much there was to discover. We had a sense that we knew what it felt like
to be Magellan or Columbus It didn’t all go smoothly. Early computer problems threatened to doom
Voyager 2. Then its radio receiver failed, forcing engineers
to use a back up. Now, after more than three and a half decades
of successful operations, the twin spacecraft are sending back information on their flight
into interstellar space. Along the way, they have revealed a solar
system rich beyond our imagining. Time after time we were surprised by seeing
things that we had not expected or even imagined: volcanoes erupting from the moon, Io, the
possibility of a liquid water ocean under the icy crust of Europa, Titan, where we found
an atmosphere, Uranus’ small moon, Miranda, which had one of the most complex geologic
surfaces we’ve seen. Even at Neptune, 40 degrees above absolute
zero, even there, there were geysers erupting. It’s the only spacecraft that has gone by
Uranus. It’s the only spacecraft that has gone by
Neptune. Everything we know about those planets, we
know from Voyager. To see those first pictures coming in from
the outer solar system, for the first time, what had been a point of light in the sky
was a place. The journey was made possible by a rare alignment
of the planets, a configuration that occurs only once every 176 years. That enabled the craft to go from planet to
planet, accelerating as they entered the gravitational field of one, then flying out to the next. The Voyagers carried a battery of scientific
equipment to collect data on the unknown worlds in their path. That included a pair of vidicom cameras, and
a data transfer rate slower than a dialup modem. They are primitive by today’s standards,
but that didn’t stop them from returning a flurry of discoveries. On Jupiter’s moon Io, Voyager’s cameras
spotted nine erupting volcanoes. They documented volcanic plumes reaching 300
kilometers into the atmosphere, at velocities of one kilometer every second. Almost two years later, on November 12, 1980,
Voyager 1 sailed down to within 124,000 kilometers of Saturn’s cloud-tops. That’s one-third the distance between Earth
and the moon. It found that Saturn’s atmosphere is almost
entirely hydrogen and helium. It is the only planet in our solar system
that is less dense than water. One year earlier, Pioneer 11 had detected
a thick, gaseous atmosphere on Saturn’s large moon, Titan. Scientists decided to send Voyager 1 to follow
up. It sent back clues to one of the most fascinating
bodies in the solar system. Titan proved to be the only object in the
solar system, other than Earth, with stable bodies of surface liquid. Not water, but vast lakes of liquid methane. Scientists could have chosen to send Voyager
1 out to Pluto. But Titan was more promising scientifically. But that meant its grand tour of the outer
planets was over. Voyager 1 headed north, above the plane of
the solar system. Five years later, and over a billion and a
half kilometers beyond Saturn, Voyager 2 reached Uranus. Like all the other planets, Uranus spins like
a top. But Voyager 2 found that it’s actually tipped
on its side. Its magnetic field reaches out in a bizarre
corkscrew tail, millions of kilometers into space. Voyager 2 discovered two new rings; thin,
dark bands of ice, rock, and dust with particles the size of a fist. Although the craft discovered 10 new Uranian
moons, the most eagerly anticipated event was a close encounter with Miranda, perhaps
the most bizarre object in our solar system. Close-ups revealed a strange and wondrous
landscape including a canyon 19 kilometers deep. Miranda may have collided with another moon,
shattered, and then by the force of its own gravity, slowly reassembled into this chunk
of rock and ice. After 12 years on the road, Voyager 2 now
sped toward its rendezvous with Neptune. The planet appears blue because methane in
its atmosphere absorbs most of the red in the light spectrum. Remarkably, Voyager 2 flew by Neptune only
35 kilometers off its charted course and only 1 second off its scheduled fly-by time. Skimming only 5,000 kilometers above the planet’s
north pole, Voyager found Neptune to be a giant ball of melted rock and ice. Cloaked in hydrogen, helium, and methane gasses,
its atmosphere is whipped by winds of 1,000 kilometers per hour. Flying in closer than any spacecraft has come
to one of the outer planets, Voyager 2 discovered at least four complete rings of ice and rock,
six new moons, and a great dark spot; a hurricane the size of Earth raging in Neptune’s southern
hemisphere. The storm circles the planet every 18 hours,
and rotates around its own axis every 16 days. Oddly, the largest of Neptune’s 8 moons,
Triton, orbits in the opposite direction to the planet’s spin. Triton was likely an independent object in
orbit around the sun, until it was captured by Neptune’s gravity. Pocked with impact craters and glazed with
methane and nitrogen ice, Triton is the coldest known object in the Solar System, at minus
240 degrees Celsius. On its surface, scientists saw jagged mountains,
high cliffs, and frozen lakes. The most bizarre discovery was the presence
of icy geysers with plumes reaching 160 kilometers downwind. Leaving Neptune, Voyager 2 snapped one of
the most remarkable pictures ever taken. Neptune and its cold moon Triton, framed by
the dim light of the Sun. Several years earlier, the Pioneer spacecraft
carried a plaque illustrating the spin state of a hydrogen atom, a man and woman set against
an outline of the spacecraft, and the position of the Sun relative to 14 prominent pulsars. The Voyagers brought their own message in
a bottle: a disk encoded with images of life on Earth, greetings in 55 languages, a selection
of music, messages, and natural sounds. And here was this Noah’s Ark of human culture
that was being sent to the outer planets, and then beyond to wander in the interstellar
darkness for a billion years. On Valentine’s Day 1990, Voyager 1 looked
homeward. And what did it find? Not the frame-filling Apollo Earth, but instead,
that one-pixel Earth. That’s here. That’s home. Thirteen years after launch, the Voyager craft
finally began their journey into the galaxy at large. They run on plutonium-powered Radioisotope
Thermoelectric Generators, a standard set up for NASA deep space missions. Because even these systems don’t last forever,
scientists have had to shut down Voyager’s instruments one by one. Among the most valuable remaining sensors
are magnetometers that can read magnetic fields that constantly sculpt the outer solar system. This region is the outer edge of a bubble
formed by the sun’s magnetic field and the solar wind. Tonight we’re going to be getting the data
back from a magnetometer roll calibration maneuver, and that maneuver actually happened
on the Voyager 1 spacecraft over 16 hours ago, and the data is finally making it back
to the earth. What we’re doing is a roll about this high-gain
antenna, and so if the high-gain antenna here is pointed out toward earth we’re going
to be rolling the spacecraft along that high-gain antenna. That roll is done so that we can calibrate
the instrument so that we know what magnetic field belongs to the sun and what component
belongs to the actual spacecraft. They’re very near the edge of the bubble
the sun creates around itself called the Heliosphere. We’re getting very close to the boundary. We don’t know how close because no spacecraft
has ever been there before, but it could be another few months, it could be another few
years, but it’s probably not much longer than that. We travel a billion miles every three years. You can’t see the bubble the sun creates
around itself because it’s invisible, but we can see an analog of it in a sink. If we turn the water on very fast and look
at the bottom of the sink, we see that near where the water hits the bottom of the sink,
it’s flowing very fast radially outward in all directions, and getting thinner until
it abruptly slows down in this thick region, and turns around and flows down the drain. The two Voyager spacecraft are both in this
thick region in our heliosphere where the wind has slowed down and is starting to go
down the tail of the heliosphere. And eventually, in hopefully not too many
more years, Voyager 1 will leave this thick region and enter interstellar space. We have a 20-watt transmitter on the spacecraft
transmitting over 11 billion miles away, and so it comes in very slowly. But every bit left that spacecraft over 16
hours ago and every bit is telling us something new that we haven’t known before. As the solar wind travels out from the sun,
it pushes against the galactic medium and abruptly slows down in a region called the
Termination shock. Outside this is the Heliosheath, where the
sun’s magnetic field is bent back by the interstellar wind. The sun’s magnetic field spins in opposite
directions on the north and south poles, creating a sheet where the two spins meet. This sheet gently ripples as it travels outward. When this sheet reaches the termination shock,
it starts to compress like water waves hitting a wall. The voyager spacecraft have now found that
these stacked up ripples of magnetic field form smaller bubbles, shown here as a computer
simulation. The discovery of this frothy character changes
our understanding of how extremely fast moving particles, called cosmic rays, enter our solar
system. When they arrive at this region, they slowly
move from bubble to bubble until they can reach smooth magnetic field lines and follow
them toward the sun. Recently, the twin Voyagers began their transition
into interstellar space. Voyager today is headed for the edge of interstellar
space. That’s the space between stars and it’s
filled with material that has been injected by the explosion of stars, matter which came
from a particular direction, creating a wind which has shaped the bubble in which the solar
system is surrounded. Since July of 2012, the solar wind has decreased,
while the galactic wind has sped up. That places the craft in what scientists call
the “magnetic highway,” where the alignment of magnetic fields allows particles from the
sun to escape, and particles from the galaxy to pour in. When either one reports a complete change
in the direction of the magnetic field, that’s when scientists will know that it has finally
exited the solar system. Meanwhile, they are delivering a whole new
view of the galaxy in ultraviolet light. From Earth, this light is normally blocked
by the haze of particles at the edge of the solar system. Scientists are able to capture this light
from other galaxies because their wavelength has been shifted slightly by their journey
through space. Because ultraviolet light reveals the location
of vigorous star birth, it is providing a new window on the evolution of our galaxy. The Voyagers will keep sending back this and
other valuable data sets until their power begins to run out. They’ll finally go dead around the year
2025. Voyager 2 will be heading south toward the
constellation Sagittarius. Travelling at 16 kilometers per second, it
is expected to pass 4 light years from Sirius, the brightest star in the heavens, 290,000
years from now. Its twin will continue on a northward track
to a relatively empty region of our solar neighborhood. They will become silent emissaries from planet
earth, symbols of our boundless curiosity and aspiration. In the words of Carl Sagan: “These Spacecraft have taught us about the
wonders of other worlds, about the uniqueness and fragility of our own, about beginnings
and ends. They have given us access to most of the solar
system, both in extent and in mass. They are the ships that first explored what
may be homelands of our remote descendants.” At the same time, Voyager’s journey into
the vast and forbidding oceans of interstellar space reminds us how closely our fate is tied
to our home planet. The twin craft will wander the galaxy undisturbed
for millions, even billions of years. They will endure long after everything man
has built has crumbled to dust. Compared to Voyager, we are living on borrowed
time, for mammalian species only last on average about a million years. Our ability to follow them into deep space
will take a new perspective on time and distance, beyond the short years and decades of human
activities. We’ll continue to track Voyager’s slow
but remarkable journey, while our civilizations and our planet change and evolve in the cosmic
blink of an eye.
Beautiful.
SpaceRip puts out great space shit!