
How Close To The Sun Can Humanity Get?
Season 4 Episode 34 | 8m 51sVideo has Closed Captions
Humanity is coming closer to touching the Sun after launching the Parker Solar Probe.
The Sun: an entity worshipped as a god throughout time and across cultures. The source of all life and sustenance for our little blue space rock, and also a force of unthinkable destructive power. But soon humanity will reach out its collective hand and come closer to touching the Sun than we ever have before with the launch of the Parker Solar Probe.
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How Close To The Sun Can Humanity Get?
Season 4 Episode 34 | 8m 51sVideo has Closed Captions
The Sun: an entity worshipped as a god throughout time and across cultures. The source of all life and sustenance for our little blue space rock, and also a force of unthinkable destructive power. But soon humanity will reach out its collective hand and come closer to touching the Sun than we ever have before with the launch of the Parker Solar Probe.
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Learn Moreabout PBS online sponsorship[MUSIC PLAYING] The sun-- an entity worshiped as a god throughout time and across cultures.
The source of all life and sustenance for our little blue space rock.
And also, a force of unthinkable destructive power.
But soon, humanity will reach out its collective hand and come closer to touching the sun than we ever have before, with the launch of the Parker Solar Probe.
[MUSIC PLAYING] NASA put humans on the moon, sent probes throughout and even beyond the solar system, and drove a minivan-size Rover across the surface of Mars.
And now, NASA will once again attempt the impossible-- reaching for the one place in the solar system we never did approach.
The Parker Solar Probe will fly within a hair's breadth of the sun itself.
Will NASA succeed where Icarus failed?
The sun-- a vast ball of incandescent gas.
100 times Earth's diameter.
Powered by the giant nuclear furnace of its core.
The energy it pumps out equivalent to a few hundred quadrillion nuclear power stations, provide essentially, all of the energy to sustain Earth's biosphere.
But that energy doesn't only come as life-giving light.
It also bursts from the solar surface.
Magnetic storms driving a constant stream of energy and potentially, destructive particles.
The solar wind, whose origin we see as the solar corona.
The corona is deeply mysterious and difficult to study.
It's visible to the naked eye only during a total solar eclipse.
We still don't understand exactly why it burns at millions of Kelvin in temperature-- far hotter than the sun's surface below it.
And its mysteries are not idle curiosities.
Outbursts from the corona-- coronal mass ejections-- present an existential threat to our civilization.
Humanity is heavily reliant on technology.
Tech that can be damaged or destroyed by solar activity.
In 1859, Earth's protective magnetosphere was disrupted by a massive coronal mass ejection, dubbed the Carrington Event, after British astronomer Richard Carrington who observed it.
Charged particles traveling at nearly 1% the speed of light bombarded the earth.
Auroras normally only visible near the poles were witnessed across the entire planet.
The brand new telegraph systems across North America or in Europe failed, but not before telegraph operators received electric shocks from currents induced by Earth's compressed magnetic field.
An outburst of similar size occurred in 2012.
It missed us.
If it had happened only one week earlier, that "end of world" prediction based on the Mayan calendar, may have been closer to the mark.
The total financial impact for such an event has been estimated at up to $2 trillion.
In 1859, we were just beginning to emerge as a technological species.
Now, such an event would take years or even decades to recover from.
So maybe it's a good idea to learn more about the sun's surface?
We already monitor it constantly with ground-based telescopes and spacecraft orbiting the earth or orbiting the sun at a safe distance.
So why do we need the Parker Solar Probe?
Well, because it won't just watch from a distance, it'll get close enough to bathe in the source of the solar wind.
The primary science objective of the Parker Solar Probe-- as stated by NASA-- is to trace the flow of energy and understand the heating of the solar corona.
And to explore what accelerates the solar wind.
To do this, Parker is packed with four instruments.
There's the field experiment, which is essentially, a magnetometer and voltage detector.
It'll directly probe the sun's electromagnetic field and will connect the sun's magnetic activity with the sources of the solar wind.
It will also measure the outward flow of the magnetic field through the pointing flux, as well as the plasma density and electron temperature.
Finally, it will detect radio waves from processes responsible for the acceleration of particles in the solar wind.
Hopefully, teaching us about how that acceleration occurs.
The solar wind electrons, alphas, and protons instrument-- or SWEAP-- will directly detect the particles that make up most of the solar wind.
The most common types are electrons, helium ions, AKA alpha particles, and protons.
It'll make detailed measurements of their kinematic properties like velocity temperature and density.
It will follow the flow of energy from the solar corona into the accelerating solar wind and connect the solar wind to its source.
Next up is the integrated science investigation of the sun or ISIS.
It will capture the most energetic particles of the solar wind-- charged particles like electrons, protons, and heavier nuclei, measuring their energies and mapping them back to their origin in the corona.
And finally, there's the wide-field imager for Solar Probe or WISPR.
Really trying hard with these acronyms, guys?
This set of two telescopes will actually produce images of the solar corona and surroundings.
From that close up, it'll achieve unprecedented resolution of the solar wind, including shocks and other interesting structures.
This will provide direct images of the plasma that other instruments are sampling from which 3D models of the corona can be made, pinpointing the source of solar winds.
Together, these instruments work in tandem, creating a complete picture of the environment near the surface of the sun.
Of course, as exciting as all of this is, the big question is, how do we make sure the sun doesn't melt them?
While we've used heat shields before on a spacecraft or rovers for entering atmospheres, this one is different.
It'll need to withstand continuous exposure over many orbits to solar radiation and intense temperatures, upwards of 1,650 Kelvin, while keeping the instruments at room temperature.
For this, a 4 and 1/2 inch the carbon composite heat shield was developed especially for this mission.
Perhaps surprisingly, one of the biggest challenges with this mission is getting the spacecraft that close to the sun, even ignoring its ability to survive there.
You'd think it'd be easy.
The sun's the biggest object in the solar system and has the strongest source of gravity.
Why not just let the spacecraft fall towards it?
It's actually much more complicated.
To escape Earth's orbit in the outward direction, you first, need to escape Earth's gravitational pull and then, accelerate to achieve a larger orbit.
To move closer to the sun, you need to first, escape the Earth and then, lose speed, which can be even trickier than gaining speed and requires just as much fuel.
Parker will use the same trick as many of our outbound spacecraft, like Voyager or Pioneer-- gravitational assists.
But instead of sling-shotting around planets to increase speed, Parker will do multiple flybys of Venus to reduce speed.
At each pass, Venus will tug on Parker in just the right way to reduce its velocity, causing it to fall into a more stretched out elliptical orbit that will take it closer to the sun.
Venus will end up traveling infinitesimally faster as it absorbs Parker's orbital energy.
In total, Parker will do seven Venus flybys.
By the end of 2024, if all goes according to plan, Parker will reach its closest approach to the sun of 6.2 million kilometers.
That's seven times closer than any human-made object has ever come.
While its orbital period will be the same as Mercury's-- 88 days-- because of its eccentric orbit, Parker will get roughly 10 times closer to the sun than the closest planet.
There it will be traveling over a blazing 192 kilometers per second.
It'll spin roughly, 11 days doing science during each orbital cycle, while spending the other 77 days in the outer parts of its elliptical orbit, when it will transmit data back home.
By mission's end, after nearly seven years, Parker will have completed 26 close approaches to the sun, five of which will be a relative hair's breadth from the sun where it will be bathed in the full force of the sun's violent outbursts.
There.
It'll gather the data we need to understand the corona and the perilous solar wind.
Humanity has been planning a solar probe since: the late '50s.
And the dream of flying to the sun is as old as the legend of Icarus.
Icarus didn't fare so well, but Icarus didn't have a carbon composite heat shield.
This time if our luck holds, we'll come close to touching our home star to unlock the mysteries of our closest stellar neighbor in space time.
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