Tuesday, July 14th, 2015. Maybe you were at work,
stressing out about a deadline. Or, maybe, you were with friends, distressing after
having to fight off your boss one too many times. LeBron James was probably
sitting at home somewhere, trying to understand how he could lose in the NBA
Finals yet again. His Cleveland Cavaliers had just fallen to the Golden State
Warriors less than a week before. South of the border, the Mexican government
was putting out a bounty on the infamous drug kingpin, Joaquin “El Chapo”
Guzman.
With everything that was happening on Earth, you’d be
excused for not looking up at the stars and realizing something historic was
going on. Space is the last thing we’re thinking about between family, friends,
work, politics, sports, and all the other little things that are always
grabbing for our attention. Out there, though, roughly five billion miles away,
humanity was getting its first close-up of the dwarf planet, Pluto.
You’re excused if you didn’t realize that, but you need to
know this was important.
The history of Pluto’s a complicated one. As early as the
1840s, men like Urbain Le Verrier were making sophisticated predictions, which
were based on Newtonian mechanics, to assert that there had to be other planets
beyond Uranus. Uranus, at the time, was the planet we thought was farthest out
in the Solar System. The problem for astronomers was that Uranus didn’t have a
steady orbit around the Sun. Something was interfering with it.
That planet wasn’t Pluto. It was actually Neptune, but for
the first time in human history, mankind was pushing the limits of the known
Solar System. Once people realized Neptune was out there, governments started
making huge observatories to start searching further and further out. Neptune
was discovered in 1846. Pluto, though, wouldn’t be found for nearly a hundred
years more.
The problem for astronomers was that Pluto was legitimately
hard to track. That’s understandable, considering the distance was far outside
the scope of most observatories that existed at the time. In 1906, the equivalent
of an outer space manhunt was declared to track down this rouge “Planet X.”
Astronomers started scanning the skies and predicting possible locations. Some
of those involved in the search even accidentally picked up images of the
wandering planet, then failed to realize they had.
The epicenter of this search was occurring at Lowell
Observatory, in Flagstaff, AZ. Created by a wealthy Bostonian named Percival
Lowell, whose pockets were deep enough to self-fund such a massive project, the
Lowell Observatory’s mission for decades was to track down this undiscovered
planet. Most people are aware that space is big, but what they don’t realize is
just how big it actually is. You have to carefully pick your battles when it
comes to taking photos out there.
So, the Lowell Observatory staff did the best they could to
make predictions about that path Pluto was travelling. It was the kind of
obsessive mission that Captain Ahab of Moby
Dick fame would have been proud of. In fact, it was a never-ending pursuit
that drove Lowell until his death in 1916. He died, never aware that he’d
actually captured faint images of Pluto, and went to his death without having
ever found his version of the white whale.
After his death, a legal battle started to brew as his widow
attempted to claim a multi-million dollar settlement from the observatory. Over
ten years, that legal battle raged, bringing the search for Pluto to a halt.
Once the dust settled and the observatory returned to work, Vesto Melvin Slipher,
the observatory director, handed the mission of finding Pluto over to a young
astronomer named Clyde W. Tombaugh. It was the beginning of the end to the
30-year mission.
Clyde Tombaugh was the kind of guy that would beat anyone
else in a game of Where’s Waldo? because
his mission for a full year was to basically do just that. Instead of finding a
happy-go-lucky, glasses wearing oddball, Clyde’s mission was to take photo
after photo of space. Then, one by one, he’d search those images for even the
slightest changes.
Over the course of six days, from January 23rd to
January 29th, he finally noticed that there was an object that
seemed to be drifting through the photographs. He had to confirm this before
making any big declarations of the world. He was looking for his smoking gun.
That came in the form of a picture taken on January 21st. As he
compared all the photographs, he found the streaking Pluto yet again, and made
a path for its movement over sets of multiple pictures.
With a predicted line of motion, the observatory was able to
take even more pictures, confirming for good that Pluto was out there. All it
took to make the news official was a telegraph to Harvard College Observatory
on March 13th, 1930. The mission to find Pluto, that began with
predictions by astronomers in the 1840s and became the obsession of Percival
Lowell in the early 20th century, was over. Clyde Tombaugh had made
history.
The discovery of a new planet created a tidal wave of
scientific investigations. It’s a curious little place out on the edge of the
Solar System, and it has some odd behaviors. Its orbit around the sun, for
instance, makes it intersect with the orbit of Neptune. Pluto moves at an angle
to the sun, and the only reason it doesn’t collide with Neptune is that Neptune’s
rotation is just a little bit slower. Otherwise, instead of planets beyond
Uranus, you’d have just asteroid belt.
Pluto’s got a couple of other quarks, just like any person.
It takes 24 hours for the Earth to make one rotation from day to night. Pluto
is a bit lazier. It takes a little over six days for it to make a rotation.
Because it rotates at an odd angle, it doesn’t have constant seasons. A quarter
of Pluto is in constant daylight, never experiencing nighttime. It’s like
living in Alaska over the summer and never leaving.
Not that you could live on Pluto if you wanted to. Its
surface is almost entirely nitrogen ice, with just small traces of methane and
carbon monoxide. There’s no oxygen, so there’s nothing to breath. It’s also
incredibly cold. We’re talking -390 degrees Fahrenheit. That would be -233
degrees for the Europeans out there. Either way, when you start talking about
temperatures that are anything below zero, you know it’s not going to be
pleasant.
Of course, the most infamous debate surrounding Pluto’s
history revolves around its status as a planet. When Clyde Tombaugh found it,
he naturally just declared it a planet. By 2003, the way astronomer’s categorized
stellar bodies had changed. There’s another object beyond Pluto, named Eris,
and it was that discovery that sparked the discussion of what made a planet.
Pluto is too small and because of its odd place in the Solar System, it no
longer made the cut as a full planet. Now it’s a dwarf planet.
So, Pluto has an odd history and place in the Solar System.
It’s also incredibly distant, which made close up observations impossible for
decades. That was the case until a group of scientists started planning to
launch a new mission to Pluto. Much like the astronomers of old days, it took a
group of science obsessed, space loving individuals to lay out a plan that
would actually get a space probe close to Pluto.
Scientists like choosing cheesy names too, so they called
their group The Pluto Underground. Established in 1989, they started lobbying
NASA to begin seriously looking into a mission that would capture close
photography of the distant dwarf planet. The biggest problem was that there was
no real understanding of how Pluto’s atmosphere behaved. How would a space
probe react once it was in orbit?
The project started picking up some serious steam in the
halls of NASA until it was declared a mission of “low importance,” which really
meant that the funds were taken out from underneath the scientists looking to
explore Pluto. There’s nothing quite like a group of angry scientists, though,
and groups like The Planetary Society
started hitting back hard at NASA. All the complaints and lobbying finally got
a new exploration program started: The New Frontiers program.
Begun in 2000, it would take six years of around the clock
research and work to create the New
Horizons probe. Even once it was off the ground, there was a period of nine
years of anxious breath holding. Would this work? Would the probe intersect with
Pluto’s orbit and get the photos people had been dreaming of for so long?
Back to July 14th, 2015, almost 175 years since
Pluto had been predicted by early astronomers. The New Horizons probe wasn’t intended to land on Pluto, but to get
close enough to take the kind of pictures that would scientist better
understand the planet. It did its job. Within a week of the probe’s flyby, new
pictures were emerging of alien atmospheres full of stellar rays, great, flat
plains that rise up into mountain ranges, and frozen rivers of nitrogen ice
flowing along the planet’s surface.
The mission to better understand Pluto is not over, though.
Two new probes, launched in May and August of 2011, are expected to pass along
Pluto sometime in 2016. These newer, more advanced probes will bring back even
more stunning imagery and scientific data of Pluto. It’s the sort of
photography that men like Clyde Tombaugh could only have dreamt of years ago.
