They might say, well, it depends upon the island where the dog lives. Then it is a true mammal. Pluto, being a medium-sized planet, would clear its neighborhood around our sun if it were at the orbit of Venus or Mercury. It would almost do so if it were at the orbit of the Earth. It would definitely do so if it were in the habitable zone of any star slightly less luminous than our own, which includes the vast majority of stars in the universe.
Therefore, if there is life beyond the Earth, one could argue that it is likely to be found on a medium-sized planet like Pluto.
And by the way: in terms of percentile, Pluto has one of the highest scattering parameters of all the planet-sized bodies in our solar system. The scattering parameter gives us great insight into the dynamics of planets in a given solar system at a snapshot of time, and therefore it allows us to create subcategories of planets based upon how they have behaved in their current or presumed past environments.
This is how the scattering parameter was intended to be used. We feel something is wrong when we look at the poster with the twins of Tethys and Earth. The problem is that dynamical requirements doing are relative whereas physical requirements being are universal. It is all interconnected. It takes a solar system village to raise a planetary child.
A lot has been made about the gap of four or five orders of magnitude between the scattering parameters of Mars and Pluto. Where are the planets with scattering parameters closer to unity?
According to theory, they could have existed, but maybe the giant planet migrations eliminated them. That might not have happened the same way in other solar systems. As far as we can tell, our solar system is the oddball.
Whatever dynamics happened elsewhere did not happen here and vice versa. So far we have studied only one solar system in great depth , so our dynamical definitions are based on a sample of one. As I discussed in a prior post , the old concept of the planets was that they are gods ruling over the Earth, each reigning in its own orbit. After we realized the planets are worlds like the Earth going around the sun, we continued to believe they are an orderly, clock-like system with no sharing of orbits.
Only in the most recent century have we realized that countless smaller bodies share and cross the orbits of all the planets, and an entirely new zone of the solar system exists beyond Neptune the Kuiper Belt where sharing orbits is normal , not an exception. No part of the solar system is clock-like when you consider how it behaves over long enough timescales.
When the IAU changed the definition of a planet to exclude all the worlds of the third zone, it was an attempt to keep the old clock-like view intact with planets that reign like gods within their own orbits.
To include Pluto as a planet is to embrace the new view of the solar system, the reality that it is a wonderfully messy, ever-changing place. Right now, most elementary and secondary education focuses on the eight largest planets, creating the outdated impression of a static solar system where everything important is closer to the sun than Neptune. Including Pluto and the hundreds of worlds in the Kuiper Belt as planets will change our perspective and change the language of the classroom.
It is a reality freed from the artificial boundaries of anthropocentrism. It is a reality full of unsolved mysteries about planetary science and our place in the cosmos. Even beyond the classroom, the public will be gripped with the excitement of discovery when we acknowledge hundreds of planets beyond Neptune. One day — I think within a century or certainly within two — we will build scientific observatories and transportation hubs on these many worlds of the Kuiper Belt.
And finally, reason number nine: what would Spock say as his spacecraft approached one of these smaller, icy worlds of the Kuiper Belt? Or if you prefer, what would Skywalker say? A year on Pluto is Earth years. A day on Pluto lasts hours, or about 6 Earth days. Pluto has a thin atmosphere of nitrogen, methane and carbon monoxide.
The atmosphere has a blue tint and distinct layers of haze. Pluto has 5 moons. The largest, Charon, is so big that Pluto and Charon orbit each other like a double planet. Venetia Burney, just 11 years old at the time, suggested the name Pluto in When Pluto was reclassified in from a planet to a dwarf planet, there was widespread outrage on behalf of the demoted planet. As the textbooks were updated, the internet spawned memes with Pluto going through a range of emotions, from anger to loneliness.
But since the release of New Horizons images showing a very prominent heart-shaped feature on the surface, the sad Pluto meme has given way to a very content, loving Pluto that would like to once again be visited by a spacecraft.
The Disney cartoon character Pluto, Mickey's faithful dog, made his debut in , the same year Tombaugh discovered the dwarf planet. There is speculation that Walt Disney named the animated dog after the recently discovered planet to capitalize on its popularity, but other accounts are less certain of a direct link. But either way, the joke connecting the two, as told in the Mel Brooks film "Spaceballs " remains:.
We were lost. None of us knew where we were. Then Harry starts feeling around on all the trees, and he says, "I got it! We're on Pluto. From the bark! Pluto is a dwarf planet that lies in the Kuiper Belt, an area full of icy bodies and other dwarf planets out past Neptune.
Soon after Pluto was detected, astronomers conjectured that other, similarly sized objects might lurk out there in the distant reaches of our planetary system. Since then, more than 2, bodies have been identified in this part of space, with the true quantity of worlds greater than km across perhaps numbering in the hundreds of thousands.
Crazy, right? Never mind that we have hundreds of countries, thousands of languages, and 8. That last criterion states that a planet must be the gravitationally dominant object in the area of space in which it orbits.
This rule makes sense for somewhere like, say, Earth, which is far more massive that the Moon and anything else along its orbital path. But out in the Kuiper Belt, where neighbouring bodies are far, far more distant than in the inner Solar System, Earth would not necessarily be able to clear its neighbourhood. In fact, if we were somehow able to tractor-beam Earth out past Neptune, our world could become gravitationally dominated by that icy giant and thus lose its own planethood.
This criterion does not allow for the geology of a world to be considered. By any geological measure — including the fact that there are surface processes acting on Pluto today — Pluto is a planet.
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