Category: pluto

Triton, Not Pluto or Eris, Is The Kuiper Belt&…

Triton, Not Pluto or Eris, Is The Kuiper Belt’s Largest World

“The result, today, is that the largest and most massive body ever to form in the Kuiper belt — 20% larger than Pluto; 29% more massive than Eris — is now Neptune’s largest moon: Triton. Today, Triton makes up 99.5% of the mass orbiting Neptune, an enormous departure from all the other giant planet systems we know of. The only explanation for its properties, especially its bizarre and unique orbit, is that Triton is a captured Kuiper belt object.

We often talk about icy moons with subsurface oceans as candidate worlds for life. We imagine large, distant, icy bodies as planets or dwarf planets in their own right. Triton was born not as a moon of Neptune, but as the largest and most massive Kuiper belt object to survive. You don’t cease to exist when you move locations, and neither did Triton. It’s the original king of the Kuiper belt, and its true origin story is a cosmic mystery that deserves to be solved.”

In October of 1846, just months after Neptune was discovered, a large moon was discovered around it: Triton. Today, Triton is a supremely unusual moon for a number of reasons, but the largest is that it rotates in the wrong direction. While Neptune orbits the Sun counterclockwise and spins counterclockwise on its tilted axis, Triton orbits in the opposite direction. The only way this could have happened is if it were a captured object. And that’s exactly what it looks like: a captured object from the Kuiper belt!

We know what it’s like and where it came from; the biggest mystery, now, is reconstructing how it came to be there. Come get the story on the true king of the Kuiper belt: Triton!

Don’t forget to follow on instagram! -> fun…

Don’t forget to follow on instagram! -> funophysics

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Which Worlds Will Survive When The Sun Dies? …

Which Worlds Will Survive When The Sun Dies?

“But the Sun will be so hot and so bright that much of the outer Solar System will be absolutely destroyed. Each of the gas giants has a ringed system; although Saturn’s is the most famous, all four of them have rings. These rings are mostly made of various ices, such as water ice, methane ice, and carbon dioxide. With the extreme energies given off by the Sun, not only will these ices melt/boil away, but the individual molecules will be so energetic that they will be ejected from the Solar System.”

When the Sun becomes a red giant, lots of changes are going to happen. Mercury and Venus will surely become engulfed; Earth and Mars will lose their atmospheres and oceans, becoming barren and charred. But even beyond that, the outer worlds and structures in the Solar System will melt and lose their volatiles. Asteroids will lose mass and become rocky/metallic cores; moons like Europa and Enceladus will melt away; the rings around the gas giants will disappear; even Pluto and the other large Kuiper Belt objects will lose their atmospheres and top layers, melting away until they’re only a rock-and-metal core.

Who will survive, who will transform, and who will be annihilated when the Sun dies? The carnage is severe, but not complete. Get all the details here.

You Won’t Like The Consequences Of Makin…

You Won’t Like The Consequences Of Making Pluto A Planet Again

“There are some out there who are desperate to save Pluto’s planetary status, and would be willing to open the floodgates and bestow planethood on every moon, asteroid, and ice ball out there that’s massive enough to be round. There are others who spend 100% of their time looking down at their feet on whatever world they’re considering when it comes to planethood, and to them, everything with enough mass will be a planet. But for the rest of us, where you are in the Universe is an inseparable part of what you are. Nothing in the Universe exists in a vacuum, and where you are determines a huge number of properties of you, regardless of whether you’re a planet, moon, asteroid, centaur, comet, Kuiper belt object, or Oort cloud object. If you want to ignore all of that — and proclaim, “round means planet” — then more power to you. But in planethood, as in most things, the full scientific story is far more interesting.”

When you say, “Pluto should be a planet,” what I hear is, “let’s ignore all of astronomy.” When you say, “we’re using a geophysical definition of a planet,” I hear, “we don’t believe in looking up.” And when you say, “we call ourselves planetary scientists, and so we get to decide what a planet is,” I hear, “we don’t care about the full suite of scientific evidence.” There is a long and interesting history to planets and planethood, and yes, the IAU definition is flawed. But does that mean, as Alan Stern and David Grinspoon contend, that we should call every object that can pull itself into a round shape a planet?

The fact is that Pluto was misclassified when we first discovered it, and the only way to “save” involves misclassifying hundreds of other objects, too. Should we?Get the other side of the story and see what you think!

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Pluto’s Surface Changes Faster Than Eart…

Pluto’s Surface Changes Faster Than Earth’s, And A Subsurface Ocean Is Driving It

“These mountains aren’t static and stable, but rather are temporary water-ice mountains atop a volatile, nitrogen sea. The evidence for this comes from multiple independent observations. The mountains only appear between the hilly highlands, after the edge of a basin rim, and young plains with flowing canals. These young plains occur in Pluto’s heart-shaped lobe, which itself was caused by an enormous impact crater. Only a subsurface, liquid water ocean beneath the crust could cause the uplift we then see, leaving the nitrogen to fill it in.”

In July of 2015, NASA’s New Horizons Mission arrived at Pluto, photographing the world at the highest resolution ever, with some places getting as up-close as just 80 meters (260 feet) per pixel. Not bad for a world more than 3 billion miles (5 billion kilometers) from home! What we’ve learned is breathtaking. Rather than a static, frozen world, we found one with tons of evidence for active, interior geology, as well as with a changing surface that renews itself and undergoes cycles, quite unexpectedly to many. There’s also not an enormous heart, but rather a massive, volatile-filled crater that caused Pluto to tip over at least once in its past, and may yet cause it to tip over again in the near future.

If you ever wanted to know how these distant, icy worlds come alive, there’s never been a better way to find out than in the aftermath of what New Horizons taught us!

Pluto’s Mysteriously Cool Atmosphere Might Hold The Key To…

Pluto’s Mysteriously Cool Atmosphere Might Hold The Key To Fighting Global Warming

“Global dimming could someday provide a geoengineering solution to counteract the effects of global warming, if our environmentally-minded efforts to curb our emissions fail. The discovery of the haze-temperature connection on Pluto demonstrates, for the first time, that there are actual cases out there where this type of effect can serve to reduce the worldwide temperature by far more than humanity’s emissions have increased it. On the surface, it provides a new hope for geoengineering scenarios to mitigate global warming. However, there are side effects associated with having pollutants and potentially toxic particulates in our clouds, and therefore our rainwater. We must ensure, before embarking down such a path, that the cure isn’t worse than the disease.”

When NASA’s New Horizons arrived at Pluto, it discovered a slew of wonderful surprises and sights. It found reddish-brown terrain, ices, a complex atmosphere with hazes, and a temperature surprise: it was 30 K (54 °F) cooler than we would have expected. There are only three factors that normally control a world’s temperature: its distance from the Sun, its reflectivity, and the gases present in its atmosphere. But on Pluto, the hazes play an incredible role, as a new paper out today reveals. These hazes, made of complex hydrocarbons formed from ionized gases like nitrogen and methane, actually add heat to the atmosphere but cool down the surface, leading to a dramatic difference that’s more than 10 times cooler than the heating effects of humanity’s contribution to Earth’s atmosphere. It makes you wonder if this might hold the key to fighting global warming here on Earth.

We may not be in control of our planet, but we’re at the controls. It’s up to us to make the right decisions, and learning all we can about other worlds in the Solar System is certainly helping!

Ask Ethan: How Can Worlds That Never Get Above Freezing Have…

Ask Ethan: How Can Worlds That Never Get Above Freezing Have Liquid Water?

“I was reading about Saturn’s moon Enceladus, and how scientists believe it has liquid water oceans beneath its water-ice crust. And yet I also read that the warmest surface temperatures are -90 celsius. How can this moon have liquid water? […] At such cold temperatures and low pressures it seems Enceladus can have water ice and water gas but not liquid. What am I missing?”

Here on Earth, water can easily exist in all three phases of matter: solid, liquid, and gas. The reason for this is simple: Earth has the right range of temperatures and pressures to experience not just the common solid and gas phases, but the liquid water phase, too. In the outer Solar System, worlds like Europa, Enceladus, and Pluto are too far from the Sun to ever reach surface temperatures high enough to create a liquid phase; it seems that water is a no-go. But there must be subsurface oceans on these worlds! Not only is there geological evidence of an ocean beneath a thick layer of ice, but on some worlds, like Enceladus, we can actually see large plumes of liquid water ejected hundreds of kilometers above the surface, like some sort of planet-scale geyser. While the increased pressure from the ice plays a role, it isn’t enough on its own; there must be other factors, too.

How do worlds that never get above freezing actually come to have liquid water on their surfaces? Find out on this week’s Ask Ethan!

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