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Hey guys, do not adjust your screens, I know
it seems a little dark, but this is what it looks like at high noon on the dwarf planet
Pluto. It takes a little more than 5 hours for light from the Sun to reach Pluto, but
it took a little spacecraft named New Horizons almost ten years! Since its closest approach
on July 14, 2015 it's been sending back incredible images and scientific data, completely redefining
what we know about Pluto, teaching us more than we found out in the entire 85 years since
its discovery. Here's what it's shown us.
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New Horizons was launched on January 19, 2006 on top of an Atlas V rocket spewing out more
than 2 million pounds of thrust. It was the first spacecraft shot directly out of orbit,
escaping the pull of the Earth and Sun with a launch velocity of over 16 kilometers per
second, the fastest spacecraft launch ever. The kind of mad science orbital trajectories
that you don't see outside of Kerbal Space Program.
A year later, it flew by Jupiter and used its gravity as a slingshot to speed toward
its encounter in the Kuiper belt.
Before New Horizons, our view of Pluto made Space Invaders look high-definition.
This is Pluto as we know it now, a planet full of more questions than answers, a far-away
world that’s redefining what we know about the icy outer reaches of our solar system.
The cameras and sensors on New Horizons were pre-programmed for the flyby, so making sure
they weren’t pointed at empty space meant hitting a spot in space just 100 km wide and
150 km tall, and arriving there within 100 seconds of when they planned… after flying
for nearly ten years!
"That's impossible, even for a computer!"
Next time you’re late for dinner, you’ve got no excuse.
So New Horizons made it to Pluto, engaged its instruments, and scienced all over that
little I dwarf planet. So what have we learned so far?
For starters, Pluto looks awesome! Before this year, this was our best view of Pluto,
and to be honest we’ve never really known much about it. Scientists expected some surprises,
and Pluto definitely hasn’t disappointed.
Pluto’s heart is its most famous feature. It’s been named Tombaugh Regio after Clyde
Tombaugh, the astronomer that discovered Pluto in 1930.
This heart is weird! Its western half, where temperatures average just 38 Kelvin, is bordered
by flowing nitrogen glaciers, and in the middle, a frozen plain made up of nitrogen, carbon
monoxide, and methane ice. Farther down we find three and a half kilometer-high mountains
made of water ice.
Those sharp mountains and Tombaugh Regio’s crater-free surface means that these features
are pretty young, at least in planetary terms. Many people expected Pluto to be a dead ball
of ice, but it’s geologically active, and scientists have no idea why.
The name Pluto is popularly associated with the Disney character, so you might expect
that when it came time to name features on this dwarf planet NASA would use warm and
fuzzy names like Disney Mountain, and The Forest of Fairy Flowers.
However, Pluto's name actually originates as another name for Hades, the Greek god of
the underworld. And so instead we have names like the Balrog Macula, Cthulhu Regio, and
Mordor Macula, which is a very long way from the Shire.
When it came to naming features on the moon Charon the researchers really let their nerd
colors shine.
In true-color images we see that Pluto should join Mars our solar system’s second “red
planet”. That color comes from compounds called “tholins” formed when hydrocarbons
in Pluto’s atmosphere are zapped with ultraviolet radiation and then rain down onto the surface.
New Horizons captured this great silhouette showing Pluto’s thin atmosphere of mostly
nitrogen gas. Pluto’s largest moon, Charon, has been equally
full of surprises. Charon is so big that it almost forms a binary planet system with Pluto.
The dark area near the moon's pole, called Mordor, might be a huge crater from an impact
large enough to have melted the moon. We don’t know for sure, but that cooling off would
explain why its surface is young and smooth like Pluto. And it’s got this enormous “mountain
in a moat” like someone just walked up and stuck a rock in it. Nobody knows what’s
going on!
New Horizons also gave us our first close-up views of Pluto’s tiny moons Nix and Hydra,
which look like potatoes. Thanks to New Horizons, here’s what Pluto’s
family portrait looks like today
New Horizons verified that Pluto can keep its crown as “biggest dwarf planet”. It’s
about 48 kilometers wider than Eris, the second-biggest dwarf in the solar system.
In a speech after the flyby, NASA chief Charles Bolden said “we have now visited every single
planet in our solar system.” Overlooking the obvious error in that statement, Mr. Bolden
you are WRONG! We are not done!
Counting our missions to Ceres and Pluto, we’ve visited 10 planet-ish objects in the
solar system, and just a handful of moons. But what about the other dwarf planets? Eris?
Haumea? Makemake? Pallas?
What about missions to Europa, or Titan? What about trojans and centaurs and comets and
trans-Neptunian objects? I didn’t even know what those were until like a week ago!
As of July 2015, there’s more than 600,000 known minor planet objects in our solar system,
from asteroids and comets to dwarf planets like Pluto. There’s a lot we don’t know
about our neighborhood, and we’re not done yet.
New Horizons is now far past Pluto, flying on into the Kuiper Belt, and it will continue
to send back new science as long as it’s got power and as long as we’re still listening.
What I wanna know is where are we going next? Stay curious.
Hey everybody, if you want to calculate Pluto time where YOU live, I've put a link to that
tool from NASA and a bunch of other awesome New Horizons science down in the description.
Make sure to subscribe, and I'll see you soon.