A brand-new NASA mission to the Sun reveals cutting-edge discoveries about Earth's star; as the Parker Solar Probe dives through the Sun's atmosphere, what it finds challenges everything we know about this strange place.
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Thanks for wathing. Follow for more videos.
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LearningTranscript
00:00There's a violent star at the center of our solar system.
00:06The immense power, the roiling, boiling surface, the massive plumes, it's ridiculous.
00:15And our planet is at its mercy.
00:18There are explosions and big giant eruptions of plasma that head straight to Earth.
00:25We have to understand these better to protect ourselves.
00:31The sun is a churning cauldron of nuclear reactions, revealing its inner workings was once mission impossible, but not anymore.
00:42We've recruited this network of spies, if you will.
00:45We've built a fleet of spacecraft that monitor the sun 24 hours a day.
00:51With the sun under close surveillance, we just might have what it takes to defend our planet.
00:58September 6th, 2017. A flash of ultraviolet and X-ray light erupts from the sun, sending a burst of radiation toward Earth.
01:25We call it a solar flare.
01:30Flares are huge explosions on the surface of the sun, throwing light out into the solar system and absolutely baking anything in its path.
01:39These are really powerful events erupting from the sun, and we are fundamentally in the line of fire.
01:44The flare is so intense, it causes radio blackouts across the side of the Earth facing the sun.
01:53And the timing could not have been worse.
01:59The problem was, at this time, there were hurricanes in the Atlantic bearing down on the Caribbean.
02:07And there were people trying to get in there and rescue folks.
02:11Radio communication between disaster relief teams goes down for most of the day.
02:18Space weather and Earth weather combine to create chaos.
02:25It's not just an academic exercise.
02:30Your very lifestyle depends on understanding how the sun behaves.
02:35We need to be able to predict what the sun is going to do next.
02:40And in order to do that, we need to have eyes on the sun, as many eyes as we can get.
02:45Three, two, one.
02:49That's why NASA has put together an elite unit.
02:52We have ignition and we have liftoff.
02:56Liftoff and liftoff on an international mission of solar physics.
03:01A fleet of daring spacecraft.
03:05We humans have come a long way.
03:07If you go back a few thousand years, people were worshipping the sun.
03:11And today, we've built a fleet of spacecraft that monitor the sun 24 hours a day.
03:17Observing it from every angle, predicting what it's going to do next.
03:21That's nuts.
03:24Leading the pack is the Solar Dynamics Observatory, or SDO.
03:30It keeps a telescopic eye on flares blasting out from the sun's surface.
03:3724 hours a day, the SDO probe is on the lookout.
03:41It's constantly vigilant.
03:43It looks at the sun at a lot of different wavelengths in exquisite detail,
03:47so that we can see exactly what sort of high-energy events are happening on the sun.
03:53The record for the longest service goes to SoHo.
03:58Our Sentinel monitoring the sun and its faint outer atmosphere.
04:03The Solar and Heliospheric Observatory, or SOHO, is the old hand at studying the sun.
04:08It's been up there for 25 years, observing not just the sun itself, but the environment around it.
04:14Instead of looking directly at it, it actually blocks out most of the light,
04:19so that we can see all these beautiful structures that surround the sun.
04:26And then, there's the new recruit.
04:28The Parker Solar Probe.
04:31Our scout going deep behind enemy lines.
04:34The Parker Solar Probe is going to give us the closest look at the sun that we have ever had in the history of humanity.
04:44We're flying so close to the sun, we're flying through the gases of its atmosphere.
04:4929 other craft make up the fleet, each with their own role to play.
04:56This fleet of spacecraft that we have, the overall mission is to observe the sun scientifically,
05:02learn about its behavior, but also, importantly, to learn about the effects that it has on Earth.
05:08Our lookout probe, the Solar Dynamics Observatory, or SDO, spots something hellish.
05:21Today's forecast for the sun is predicted to be 10,000 degrees Fahrenheit,
05:25with winds of up to 600 miles per second.
05:29And a pretty decent chance of rain.
05:32You don't want to be in this rainstorm, because your umbrella isn't going to help you.
05:37Solar rain isn't water, it's plasma. Hot plasma.
05:42Rather than a solid, liquid, or gas, the entire sun is made up of a strange fourth state of matter.
05:51Plasma.
05:58Plasma is just simply gas that's very hot.
06:01So hot it's lost some of its electrons and become electrically charged.
06:05And the wonderful thing about plasma is that once it has that electric charge,
06:09you can direct it with a magnetic field.
06:12And the sun has the most powerful magnetic field in the solar system.
06:18It twists and flows through the entire star.
06:24The sun's magnetic field is incredibly complicated.
06:26There are lots of loops of magnetic lines coming out of the sun's surface.
06:33As you go above the surface, the magnetic field begins to control where the gas can go.
06:39And you get these beautiful loops and other structures above the sun that are just showing you where the magnetic field is.
06:45The SDO spacecraft's jaw-dropping videos of rain on the sun show plasma flowing along huge, looping magnetic field lines that have punched through the sun's surface.
07:00Because the surface of the sun is a plasma, and these loops of magnetic fields are coming out of it, it draws that plasma up, which then cools and rains down as a plasma rain.
07:13Tracking these loops of magnetic field and plasma could help explain solar flares.
07:22And it could give us some warning.
07:26September 2017.
07:30Minutes before the devastating mid-hurricane radio blackout,
07:33our solar lookout spotted an explosion on the surface of the sun.
07:40Suddenly you have this tremendous flow of energy and an explosive release of it.
07:44And we call this a solar flare.
07:46This is SDO's specialty of observation.
07:50The craft tracked the magnetic loops above the sun's surface.
07:56They were highly unstable.
07:57SDO takes very detailed pictures of where the flows are.
08:04You can actually see gas flowing from one place to another.
08:07You can see the magnetic loops.
08:11These magnetic flux loops are kind of like wires carrying electricity.
08:16When they're on their own, they're fine.
08:18But if they get too close, they can connect and short circuit.
08:21And then you get a tremendous release of energy.
08:23The Ghostbusters were really onto something.
08:27Don't cross the streams.
08:31The contact between magnetic loops
08:34released an epic explosion of high-energy light.
08:39This radiation altered our planet's atmosphere.
08:45Radio waves jammed, causing blackouts at the worst possible moment.
08:49Solar flares are happening on the sun 90 million miles away.
08:55Who cares, right?
08:57Well, think of it this way.
08:59A really good solar flare could be the equivalent of, oh, say,
09:0210 million hydrogen bombs going off.
09:04How's that sound?
09:06Solar flares happen a lot.
09:08And they do affect us.
09:10They have affected us in the past, and they will again in the future.
09:13But the sun's twisting magnetic fields do more than just disrupt our communications.
09:19And when we see flares, we've got to keep an eye out on those.
09:23But sometimes there's something even bigger.
09:26The sun launches huge clouds of plasma across the solar system.
09:32All of that material can come to the Earth and really mess things up here.
09:38Blow out our power grid, destroy our satellites, even physically harm our astronauts in orbit.
09:43Can the solar fleet safeguard Earth?
09:46November 5th, 2018. An explosive cloud of plasma hits the Parker Solar Probe as it orbits just 15 million miles from the sun.
10:09We have this fleet of spacecraft out there viewing the sun, and they're also under attack by the sun.
10:18There are explosions coming from its surface.
10:23It's not just light, but explosions of hot plasma.
10:27And the Parker Solar Probe got blasted, and yet it survived.
10:31A huge blast of high-energy charged particles launches into the solar system at millions of miles an hour.
10:42A coronal mass ejection.
10:44But our solar scout is prepared for the onslaught.
10:53The Parker Solar Probe gets very close to the sun, and it has a heat shield to protect it.
10:58But if it gets hit by a coronal mass ejection, it has to be protected against that as well.
11:02And so it's been radiation-hardened to survive such an impact.
11:05Could these blasts pose a danger to our planet?
11:12A coronal mass ejection accelerates subatomic particles, and it's not a little bit of particles.
11:18It could be up to a billion tons of them screaming across the solar system at high speed.
11:23And this is something we need to take very seriously.
11:29To understand these dangerous blasts of plasma, we have to look at their source.
11:37An area around the sun known as the corona.
11:41The sun's corona is kind of like its atmosphere.
11:44You can think of the sun itself as being a ball of gas.
11:47And then outside of that is this ethereally thin gas stretching out for millions of miles.
11:54The corona is a difficult thing to study.
11:57Because the surface of the sun is so bright, it blocks our view.
12:02We can only see the corona during a total solar eclipse.
12:07When the moon blocks the sun's bright glare.
12:11Astronomers, though, we're impatient.
12:14We don't want to have to wait for a total solar eclipse, which only happens once or twice a year.
12:18So we figured out a way to make an artificial one.
12:20And it's really simple.
12:23One member of the solar fleet has it covered.
12:27Our solar sentinel, SOHO, creates its own eclipse by obscuring the blinding sun with a circular plate in front of the probe's camera.
12:38Sometimes the best solution is the simplest solution.
12:43You know, instead of trying to make a sensor that could actually see the full dynamic range of the sun's light, you know, why not just block out the light that we don't need?
12:52In July 2012, SOHO spotted a huge chunk of the corona blasting off into the solar system.
13:02Seconds earlier, another probe monitoring the solar surface spotted a bright flare.
13:10Were these events connected?
13:15If a flare goes off, it can disrupt those loops.
13:19And if you get the right kind of disruption, the whole thing can just blow open.
13:23And then you have a tremendous amount of billions of tons of hydrogen blown off into interplanetary space.
13:30And that's a coronal mass ejection.
13:36Coronal mass ejections are solar flares on steroids.
13:40If a solar flare was a firecracker, a coronal mass ejection is more like an atom bomb.
13:45And if a coronal mass ejection comes our way, it hits hard.
13:58The first thing it does is it compresses Earth's magnetic field and then it wraps around the Earth.
14:05And this causes the magnetic field itself to rearrange, reconnect and streams of particles travel down those magnetic fields toward our poles
14:13and impact the atmosphere.
14:16Our shields are up, but they are able to penetrate our shields, our shield being our own magnetic field.
14:22Once they breach our defenses, the particles of a coronal mass ejection can wreak havoc.
14:31In August of 1972, tensions were running high in Vietnam.
14:35Two dozen sea mines detonated at the same time when their magnetic sensors were tripped.
14:46A satellite was lost because of the electromagnetic pulse that ripped through it.
14:51And an air force sensor detected what looked like a nuclear explosion somewhere here on the planet.
14:58Fortunately, scientists quickly found the real culprit.
15:01A coronal mass ejection had ripped through the Earth's magnetic field and triggered magnetic sensors.
15:10The crisis soon de-escalated.
15:16The sun is an immense ball of plasma 860,000 miles across.
15:22We are not going to be able to stop it from doing whatever it wants to do.
15:25What we can do is learn to predict what's going to happen, so we're doing that now.
15:36Our new fleet of solar observers are our first line of defense.
15:43The sun is a little over 90 million miles from Earth.
15:47It takes light a little over eight minutes to get from there to here.
15:49As rapidly as a coronal mass ejection is traveling, it still takes a few days to get here.
15:58We can watch the sun to see, is there going to be an event?
16:02Or is an event starting?
16:04And these satellites can then tell us, hey, you better be careful.
16:07You might need to batten down the hatches on Earth.
16:08But there may be an earlier clue the fleet can watch out for.
16:16Vast dark regions moving across the solar surface called sunspots.
16:23We know that this is the wind up before the release.
16:27This thing is getting ready to blow.
16:28In March of 1989, a solar eruption caused blackouts across Canada.
16:50And malfunctions onboard the space shuttle.
16:52We've been seeing some erratic pressure signatures out of tank three, as well as some manifold pressure spikes in that system.
17:01Eleven years later, the sun emitted a flare that was so powerful, it blinded the solar fleet's sensors.
17:11Eleven years after that, the Earth had a near miss with the most powerful coronal mass ejection ever recorded.
17:18The sun has a very predictable, but actually quite mysterious cycle of activity.
17:25It gets very, very active every eleven years, and then it settles back down to more of a peaceful existence.
17:31This eleven year cycle has astronomers scratching their heads.
17:36One thing we do know is that violent solar events seem to be preceded by dark patches on the solar surface.
17:45Sunspots.
17:48Sunspots are large areas on the surface of the sun, much bigger than the Earth, that are caused by incredibly strong magnetic fields disrupting the flow of plasma.
18:00And every eleven years, these dark spots grow in number.
18:05Like clouds gathering before a storm.
18:08When you start seeing more and more sunspots, there's an expectation that you're going to see more intense and more frequent solar flares.
18:20But what drives this eleven year cycle?
18:23It's kind of ironic that one of the most predictable things about the sun is also the most mysterious.
18:28We've been puzzling over the sunspot cycle for generations, and now finally we have spacecraft headed to the sun to try to give us some answers.
18:41The SOHO, SDO, and STEREO spacecraft monitor the sun's atmosphere using ultraviolet telescopes.
18:50They spot flashes of high energy, ultraviolet light moving across the sun.
18:56These waves of light could be connected to the cycle of sunspots, and to the sun's outbursts, because everything we see on the sun's surface is controlled by violent processes deep in its interior.
19:18The sun is a very simple onion.
19:25At the very, very center is the core, where the nuclear fusion happens.
19:30A layer surrounding that is known as the radiative zone, where most of the energy gets pushed out through radiation.
19:37Then surrounding that is something called the convective zone, where there's great plumes and chains of plasma moving up and down, up and down.
19:48But unlike an onion, the layers spin.
19:53There are currents inside the sun that we don't see from the surface.
19:58Layers of the sun deep down inside are rotating at different rates than the layers above.
20:03So it turns out the inner part of the sun is rotating at maybe three times more rapidly than the outer part of the sun.
20:10We also can see on the outer part of the sun that the equator is rotating more rapidly than the pole.
20:20These layers of plasma grinding against each other generate the sun's enormously powerful magnetic field, and give rise to sunspots, plasma loops, and solar flares.
20:32This differential rotation takes the field and starts twisting it around the sun.
20:40So as the magnetic field gets too twisted, it starts knotting up and these knots start bubbling up to the surface, and that's what we're seeing actually with the sunspots.
20:48And that's why you see all these wonderful loops and prominences coming off the sun.
20:54Once the magnetic fields start twisting and interacting, they can direct the plasma into vast rivers and loops, both above and below the surface of the sun.
21:01Why these events flare up every 11 years is a mystery.
21:10But now, new observations from the solar fleet could provide a clue about what triggers the solar cycle.
21:18Giant, moving magnetic fields beneath the sun's surface.
21:23We think that the ultraviolet light flickers are telling us where the magnetic field is.
21:33In the course of the 11-year cycle, the sun's magnetic fields begin to move down from the poles, closer and closer to the equator.
21:41As the magnetic field lines move through the star, they carry huge amounts of plasma with them.
21:46The magnetic field lines act like shepherds for the plasma underneath the surface, and they push plasma down to the equator of the sun.
22:00The magnetic fields trap enormous amounts of plasma, like water behind a dam.
22:07Until eventually, the floodgates open and the plasma comes rushing out.
22:12When the magnetic fields meet, they cancel each other out and release the plasma, which goes as a tsunami wave back to the poles.
22:23When that plasma rebounds from the equator and hits the magnetic field coming down from the poles at the mid-latitudes, you get a huge burst of magnetic activity.
22:33Magnetic activity that triggers sunspots and loops also explains the 11-year cycle.
22:39We think that this relationship between the magnetic fields, the ultraviolet flickers, and the plasma drives the 11-year cycle.
22:52We think this is what's actually doing the work.
22:56The solar cycle has wound down for now.
22:59But once the next plasma tsunami rushes through the sun, our star will kick-start into action again.
23:09Over the next few years, we're going to start to see more sunspots, more activity, more flares, more ejections, and more space weather that we have to deal with.
23:19Our fleet of solar spies is poised and ready.
23:29But flares and coronal mass ejections are not the only solar attacks we have to shield ourselves against.
23:35There's a strange, invisible force flowing through the entire solar system.
23:42There is this great wind of high-energy particles from the sun, a million-mile-an-hour wind.
23:47And it can be deadly.
23:49In November 2019, the solar fleet watched as Mercury sailed across the sun.
24:10Mercury is the closest planet to our sun in our solar system.
24:17So it's on the front line, receiving all of this radiation, an incredible amount of energy.
24:22And it's such a tiny planet.
24:24Temperatures on the innermost planet's surface reach 800 degrees Fahrenheit.
24:30But scientists discovered something unexpected on Mercury.
24:34Frozen pools of water, hidden in its craters.
24:41It's one of the last places in the solar system you might expect to find ice on Mercury, one of the hottest planets in the solar system.
24:48Despite the overall really high temperatures across the whole planet, there are regions, typically deep within craters, that are permanently shadowed.
24:57So there's never direct sunlight on those regions of Mercury.
25:01And you can keep things as cold as ice in those craters.
25:05But where did the ice come from?
25:08When we first saw that there was ice on Mercury, we thought something must have brought it there.
25:13Something like a comet, which is made out of ice.
25:16But there's a new idea that maybe the materials that make this ice are actually coming from the sun.
25:23The sun creating ice sounds strange.
25:30But recent research shows it's not as crazy as it seems.
25:35We often think of space as being empty.
25:38But in fact, we are bathed in a wind, a million mile an hour wind of high energy particles from the sun all the time.
25:45The solar wind.
25:46A stream of subatomic particles called protons constantly flow out from the sun in all directions, bombarding the planets of our solar system.
25:59The solar wind is so strong when it hits Mercury that it can break down some of the minerals and rocks on its surface into their constituent parts.
26:11And those parts, especially if they have oxygen in them, can go to reform and form water, which if it forms in the right place can then stick around.
26:21Protons in the solar wind combine with oxygen to form water molecules.
26:27They condense and freeze in craters which never see sunlight.
26:32So even on the sun's closest neighbor, ice builds up.
26:39But the solar wind doesn't stop at Mercury.
26:43The solar wind has a tremendous impact on the worlds of our solar system.
26:52We think it's responsible for the planet Venus becoming this hell hole of heat.
26:57Up until as recently as 700 million years ago, Venus was a lush water world with conditions suitable for life.
27:06But the solar wind blasted away the water vapor and oxygen from Venus's atmosphere, leaving carbon dioxide to dominate, trapping the sun's heat and causing surface temperatures to skyrocket.
27:21Mars was once habitable too.
27:25But the solar wind quickly took care of that as well.
27:30We believe that billions of years ago, Mars had an atmosphere and had oceans and rivers that looked a lot like Earth. It was gorgeous.
27:42But that solar wind stripped away the Martian atmosphere and turned it into the barren wasteland that it is today.
27:49And Earth is in the line of fire too. It's bombarded every day with solar wind particles.
28:00So, how has life survived?
28:03One of the things we really take for granted is how well protected we are here on the Earth.
28:08The atmosphere absorbs a lot of harmful things from space and from the sun as well, but also our magnetic field deflects the solar wind around us and we still have an atmosphere.
28:16And when the charged particles come from the sun, the magnetic field lines trap those charged particles and redirect them to the poles of the planet.
28:26The physical effect, the direct physical effect of getting bombarded by these particles, they can generate the aurora borealis, the northern lights, and these are spectacular and beautiful.
28:36Auroras are beautiful, but they're also the front line in the battle between Earth and the solar wind.
28:47Without our protective shield, we'd suffer the same fate as Venus or Mars.
28:53But there is a mystery surrounding the solar wind.
28:56One of the things we know about the solar wind is that it is hugely energetic, a million miles an hour. What gives it that energy?
29:05Astronomers think the source of the solar wind lies in the inner corona.
29:10The atmosphere of the sun revealed by our solar sentinel, SOHO.
29:17SOHO's data shows that near the sun's surface, the wind speed is close to zero.
29:23But by the time the wind gets to the outer corona, it accelerates to 720,000 miles an hour.
29:33Something happens mysterious between the surface of the sun and the corona that gives a punch to the solar wind.
29:41To investigate, we need to visit the corona.
29:46So NASA sent a scout on a daring mission behind enemy lines.
29:54The Parker Solar Probe, that's a daredevil. This is designed to dive bomb the sun.
29:59The sun.
30:12The sun exerts a hostile influence on the planets of our solar system.
30:19The solar wind.
30:21It's fast. It's lethal.
30:24But we don't know how it works.
30:27We have spacecraft between us and the sun that can actually see what's coming toward us and how it will impact us.
30:33But what scientists have never been able to explain is what actually accelerates the wind away from the sun.
30:39This has been one of the biggest mysteries of the sun so far.
30:44For decades, we had no way of solving it.
30:47Until now.
30:48There really are some of these wonderful moments when you're a scientist, and I was actually at the launch of the Parker Solar Probe, standing right next to Dr. Eugene Parker, who the probe was named after.
31:01Lift off of the Parker Solar Probe.
31:03Long ago, he had proposed the sun probably had a wind of particles that affected the Earth. And people basically laughed at him. But he was proven right over time. And as that giant Delta rocket slowly went up from the pad, he and I both got to be bathed in that light and smile.
31:19There has been no spacecraft ever in human history to fly through the corona, the very atmosphere of the sun.
31:30Didn't work out well for Icarus, and we hope it works out well for Parker.
31:34The thing about going near the sun is the closer you go to it, the closer your temperature gets to its surface temperature. And its surface temperature is 6,000 degrees, which vaporizes metal easily.
31:50Surviving close to the sun is a big ask. But reaching the sun, that's an even bigger challenge.
31:56It's very hot. It tends to melt your spacecraft. That's the obvious problem. A less obvious problem is, it's just hard to get there.
32:07This is something I think that is very hard for most people to grasp. There have been suggestions of, you know, let's send all our nuclear waste into the sun or our trash or whatever.
32:17And it turns out to be very difficult to drop anything into the sun.
32:20The reason is, the Earth is circling around the sun at 67,000 miles an hour.
32:28That's good, because that means we don't drop into the sun. We stay at the same distance.
32:34If you do want to drop into the sun, you have to lose that velocity, and that's a lot of velocity.
32:41To lose speed, the Parker Solar Probe swings by Venus, performing a gravitational slingshot in reverse.
32:51Now, usually, a gravitational slingshot gives us more velocity. So if we're flying out to Pluto, for example, we might whip the spacecraft around the planet Jupiter.
33:00It actually takes the spacecraft and gravitationally slingshots it forward, making it go faster.
33:06The thing that we have to do with Parker Solar Probe is the opposite. We're going to use a gravitational slingshot, but not to speed it up, to slow it down.
33:12Parker's gravitational maneuvers send the craft on a trajectory inside the sun's extended corona, closer to the sun than any spacecraft before it.
33:26This probe actually dives really deep toward the sun, so it's actually going through some of this coronal material and can actually observe it directly in a way that other probes can't.
33:38Using its extreme ultraviolet telescope, Parker spots vast, dark regions below.
33:47There's really interesting regions called coronal holes where you can see, literally, deeper into the sun.
33:57Coronal holes are areas of the sun's corona where the atmosphere is cooler and less dense.
34:03And when the probe passes over a hole in the corona, it gets more, it gets a bigger blast of the solar wind.
34:13These coronal holes appear to be the source of the solar wind.
34:17We think it's through these holes that the solar wind is able to escape the sun.
34:23The big question is, how does the solar wind actually accelerate away from the sun?
34:28It seems to defy logic.
34:33You would think that as something leaves the source, it would probably start to slow down or at least stay the same speed.
34:39But this doesn't. It gets faster.
34:42Something is accelerating the solar wind. It gets faster and hotter as it moves away from the surface of the sun.
34:49And the mechanism is a mystery.
34:51To solve the mystery, our solar scout dives close to the sun.
34:55Not to see what's going on, but to listen.
35:00That sounded spooky. That sounded really spooky.
35:19You know, for something that's so big and powerful, it's very gentle sounding.
35:25It really, um, you know, disguises the fact that it's incredibly destructive and would kill me in an instant.
35:32These strange sounds could actually reveal what gives the solar wind its destructive power.
35:39Fluctuations in the sun's magnetic field generate waves that roll through the particles of the solar wind.
35:49These acoustic waves transport particles with them. They give them energy.
35:53Think about a surfer actually going down the surface of a wave, going faster and faster all the time.
35:57These waves could be what accelerates the particles in the solar wind from zero to 720,000 miles an hour.
36:08Giving them the momentum they need to reach far into the solar system.
36:13The solar winds travel just incredible distances. You know, they go past the Earth, past Jupiter.
36:19They've even been seen past Pluto.
36:24It really does pack a wallop even all the way at the edge of our solar system.
36:29One of the things that really surprised me is that Pluto, there are bits of its atmosphere being blasted off by the solar wind all the time.
36:36Tons of atmosphere a day are being lost from Pluto.
36:39The solar wind is powerful enough to blast past the planets to the very edges of our solar system.
36:49When we sent members of the solar fleet to investigate, we witnessed a battle between the sun and interstellar space.
36:59A battle that could decide the fate of our planet.
37:03The sun blasts the solar system with a storm of particles. The solar wind.
37:22But how far does that wind reach?
37:24For 40 years, the oldest members of the solar fleet have been on a long-range reconnaissance mission to find out.
37:35The Voyager program was a wonderful idea, a grand tour of the outer solar system in the latter part of the 1970s.
37:44In fact, both Voyagers have traveled so far now that they've effectively reached the outer edges of our solar system.
37:49That boundary zone where the sun's influence wanes and the stars take over.
37:55Over 11 billion miles away, the Voyager probes cross over into interstellar space.
38:03But have they reached the edge of the solar wind?
38:07Voyager 2, it was able to sample the environment around it and found the usual mix of solar wind particles give way to a different flavor of particles with different energies.
38:18The general interstellar mix of particles that are just hanging out in our galaxy.
38:25The solar wind actually smashes into and shocks up against the gas of the interstellar medium.
38:31We had discovered the edge of our solar system and it was much more dramatic, much more active than we anticipated.
38:36Interstellar space is violent and dangerous, teeming with lethal radiation.
38:47Supernova blasts and colliding neutron stars send cosmic rays across the galaxy straight toward our solar system.
38:56But these deadly threats are stopped in their tracks.
39:02We really do live inside kind of a protective bubble that's being blown by the solar wind.
39:09You see, as the solar wind moves out into our solar system, it carries with it the sun's magnetic field.
39:14That magnetic field protects us from the highest energy particles the universe can come up with, cosmic rays.
39:20In some cases, a single proton can have as much energy as a 100-mile-an-hour fastball.
39:26Without this protective bubble, called the heliosphere, cosmic protons would smash through your cells, damaging your DNA.
39:34Ironically, the solar wind is deadly.
39:39But without it, we wouldn't be here.
39:43Like we saw with Mars, the solar wind has the ability to wipe out life on Earth.
39:49But out there in the furthest reaches of our solar system, it's defending life on Earth.
39:55So in a way, it's a giver of life and it takes life, a yin and a yang.
39:59And now, for the first time, the Voyager probes have looked back at the heliosphere from the outside,
40:10revealing what our solar system looks like as it moves through space.
40:16Something that we lose sight of, sitting here on Earth, watching the sun go around, watching the planets go around,
40:22is that the sun itself is actually hurtling through space really, really fast on an orbit around the center of our galaxy.
40:32If our sun were perfectly stationary, then the heliosphere would be a perfect sphere.
40:39But because it's moving, it's plowing through that interstellar medium.
40:43And so that makes one end shorter and the other end longer.
40:49And new research is showing it's even more complicated than that,
40:53where we might have like a double tail, almost like a buttery croissant surrounding the sun.
40:58Our sun shapes our world and protects us from the dangers of interstellar space.
41:08It's the engine that drives the entire solar system.
41:13And now, for the first time, our fleet of solar spacecraft shows us how it works.
41:21We're pretty familiar with the sun, right?
41:25You see it all the time during the day, lights up the Earth, provides us with heat.
41:29But observing it with all these other satellites, all these observatories,
41:33has shown us a side of the sun that we knew nothing about.
41:38We have this whole fleet of spacecraft orbiting the sun, taking observations,
41:42in all of these different wavelengths, X-ray, ultraviolet, optical, infrared.
41:46They tell us about the functioning of the sun from its outer atmosphere down to its deep core,
41:52and give us a window into its functions and its evolution.
41:57Put them all together, and we finally have an understanding of our source of life itself.