Pluto is thought to possess a subsurface ocean, which is not so much a sign of water as it is a tremendous clue that other dwarf planets in deep space also may contain similarly exotic oceans, naturally leading to the question of life, said one co-investigator with NASA’s New Horizon mission to Pluto and the Kuiper Belt.
William McKinnon, professor of Earth and planetary sciences in Arts & Sciences at Washington University in St. Louis and a co-author on two of four new Pluto studies published Dec. 1 in Nature, argues that beneath the heart-shaped region on Pluto known as Sputnik Planitia there lies an ocean laden with ammonia.
The presence of the pungent, colorless liquid helps to explain not only Pluto’s orientation in space but also the persistence of the massive, ice-capped ocean that other researchers call “slushy” – but McKinnon prefers to depict as syrupy.
Using computer models along with topographical and compositional data culled from the New Horizon spacecraft’s July 2015 flyby of Pluto, McKinnon led a study on Sputnik Planitia’s churning nitrogen ice surface that appeared this past June in Nature. He is also an author on the recently released study regarding the orientation and gravity of Pluto caused by this subsurface ocean some 600 miles wide and more than 50 miles thick.
“In fact, New Horizons has detected ammonia as a compound on Pluto’s big moon, Charon, and on one of Pluto’s small moons. So it’s almost certainly inside Pluto,” McKinnon said. “What I think is down there in the ocean is rather noxious, very cold, salty and very ammonia-rich – almost a syrup.
“It’s no place for germs, much less fish or squid, or any life as we know it,” he added. “But as with the methane seas on Titan – Saturn’s main moon – it raises the question of whether some truly novel life forms could exist in these exotic, cold liquids.”
As humankind explores deeper into the Kuiper Belt and farther from Earth, this means to McKinnon the possible discovery of more such subsurface seas and more potential for exotic life.
“The idea that bodies of Pluto’s scale, of which there are more than one out there in the Kuiper Belt, they could all have these kinds of oceans. But they’d be very exotic compared to what we think of as an ocean,” McKinnon said.
“Life can tolerate a lot of stuff: It can tolerate a lot of salt, extreme cold, extreme heat, etc. But I don’t think it can tolerate the amount of ammonia Pluto needs to prevent its ocean from freezing – ammonia is a superb antifreeze. Not that ammonia is all bad. On Earth, microorganisms in the soil fix nitrogen to ammonia, which is important for making DNA and proteins and such.
“If you’re going to talk about life in an ocean that’s completely covered with an ice shell, it seems most likely that the best you could hope for is some extremely primitive kind of organism. It might even be pre-cellular, like we think the earliest life on Earth was.”
The newly published research delves into the creation – likely by a 125-mile-wide Kuiper Belt object striking Pluto more than 4 billion years ago – of the basin that includes Sputnik Planitia.
The collapse of the huge crater lifts Pluto’s subsurface ocean, and the dense water – combined with dense surface nitrogen ice that fills in the hole – forms a huge mass excess that causes Pluto to tip over, reorienting itself with respect to its big moon.
But the ocean uplift won’t last if warm water ice at the base of the covering ice shell can flow and adjust in the manner of glaciers on Earth. Add enough ammonia to the water, and it can chill to incredibly cold temperatures (down to minus 145 Fahrenheit) and still be liquid, even if quite viscous, like chilled pancake syrup. At these temperatures, water ice is rigid, and the uplifted surface ocean becomes permanent.
“All of these ideas about an ocean inside Pluto are credible, but they are inferences, not direct detections,” McKinnon said, sounding the call. “If we want to confirm that such an ocean exists, we will need gravity measurements or subsurface radar sounding, all of which could be accomplished by a future orbiter mission to Pluto. It’s up to the next generation to pick up where New Horizons left off!”
Sometimes I’ll be talking to someone and the topic will come around to personal ideals, or where we see technology or humanity in the future, or different political views or something. And I’ll say something about how our infrastructure is moving toward autonomization, or how I want to be one of the first Mars settlers, or how if we used money to further our work, rather than using work to make money (money as a means, not an end), then we could accomplish so much more as individuals and in turn work as a global community to advance society (that’s just how I see it).
The retort to my ideals and values is always “that’s just human nature.” People are greedy, but that’s just human nature. People want power, but that’s just human nature. People will take advantage of other people, but that’s just human nature. People will always believe the politicians or media rather than doing their own research, but that’s just human nature. People will always get angry over stupid things instead of controlling their temper, but that’s just human nature.
To that I say, why can’t we change human nature? Why does it have to be this to be this way? Why do we, as a society, generally accept that this is the way it’s always been done and therefore there is no other way to live? Why must we keep to outdated traditions? Why, when we all joke about money being the ultimate evil, do we not try to change systems that so clearly take advantage of us?
“People wouldn’t work if they didn’t make money.” I would still work. I would still go to school. I would still try to learn and become knowledgeable and advance my life so that I felt fulfilled and happy. I would still try to actively make a difference in the world, still try to inspire and teach others, still try to give the world something I hope is good.
“You might, but most people wouldn’t.” Then the problem isn’t me. The problem is them. The problem is that we willingly perpetuate the disgusting lie that people need to be rewarded with material goods in exchange for their work. That nature does not abide by the laws of our society, that the universe will not wait for us to figure things out.
They say that if the world economy crashed tomorrow, human society would collapse. Anarchy would reign. Where is the sense in that? Why have we let this false notion of material gain determine the stability of our civilization?
There are people out there who work every day to push humanity a little bit farther. People who study diseases and find cures. People who study plants and animals and figure how they live, and how they affect our world, and how we affect theirs. People who build rockets, hoping to send us to Mars so that humanity may realize the dream of becoming immortalized, forever searching the cosmos for other species who may be searching for the same answers as us.
When you say “But that’s just human nature,” what you’re really saying is “People are lazy and violent and greedy.” You give the best of our species no credit for what they have proven to be true: that we are explorers, that we are intelligent, that we are capable of creating great things and inspiring others to do the same. We should be ashamed of the people who refuse to work, be ashamed of the people who use others to their advantage, be ashamed of those who try to hold us back from achieving greater things. We should not ask “Does it benefit me?” but rather, “Does it benefit humanity?”
Maybe it’s just me. Maybe I’m crazy for holding people to high standards and praising the successes of the best of us, of those who work in the interest of our species, of our world. Maybe I should stop trying to inspire people. Maybe I should drop everything I’m doing because I’m not getting paid a lot of money for what I love to do. Maybe I should give up on my goals because they are too grandeur for the reality of the world that others try to make me believe is impossible to change.
But you know what? I’m not going to stop. I’m not going to give up. I’m going to fight this fight every day because I have been what I now hate most and I know that I am human, and I changed. If I could, why can’t I try to change others, too, to encourage unity and education and humble pride in our work, knowing we gave the world a little more good than we ever thought we could bring to it. I want to help foster a world where instead of condemning these ideals, we celebrate them. Where civilization does not hinge on fictional numbers, where resources are used to the benefit of all our species, where genuine knowledge and personal fulfillment are the pinnacles of success, and the entire world celebrates each new step our species takes on its way to discovering this universe.