Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff Lauren Vogelbaum here. Back in two thousand and six, to the puzzlement of many in the non scientific public and some astronomers as well, the International Astronomical Union decided to demote Pluto from its status as a full fledged planet. Instead, the IAU decided what had been considered the most distant of the nine planets in our Solar System actually belonged in a new category of dwarf planets. This category also includes Series, the largest object in the asteroid belt between Mars and Jupiter. The IAU's reasoning was that Pluto only had two of what they had decided were the three characteristics of a planet. That it is in orbit around the Sun, that it has sufficient mass for its self gravity to overcome rigid body forces and give it a nearly spherical shape. And that it has cleared the neighborhood around its orbit of other objects, a meaning that it's either collided with, captured, or driven away smaller objects nearby. Pluto flunked that last test because it shares its orbit with the Kuiper Belt, a sort of doughnut shaped disc of thousands of smaller icy objects beyond Neptune that Pluto has failed to clean up gravitationally speaking, the ii used decision, which was voted on by a very small percentage of the world's astronomers and planetary scientists, was a controversial one. After a debate in twenty fourteen among scientists sponsored by the Harvard Smithsonian Center for Astrophysics, the majority of the non expert audience voted for a simpler definition of planet, basically that it has to be spherical, an orbit around a star or the remnants of one. This definition included Pluto, and that audience aren't the only people who feel this way. In a paper published in the journal Icarus in February of twenty nineteen, a team of planetary scientists analyzed more than two centuries worth of scientific studies and found that, with the exception of one paper published in eighteen oh two by British astronomer Sir William Herschel, nobody talked about the non sharing of an orbit as a criterion for distinguishing planets from non planets. To the contrary, the researchers found that scientists routinely described what we now know to be asteroids as planets until the nineteen fifties, because that is when our instruments became sensitive enough to show that asteroids had geophysical differences, namely, they weren't massive enough to be rounded. The researchers wrote in the paper, We therefore conclude that the argument made during the IAU planet definition controversy that planet sized Kuiper Belt objects should be classified as non planets because they share orbits is arbit and not based on historical precedent before the article. This episode is based on how stuff Works. Spoke via email with paper co author Philip Metzger, a planetary scientist at the University of Central Florida. He explained that the ia used emotion of Pluto largely has been disregarded by planetary scientists. A quote in science, we classify objects in ways that are scientifically useful. The definition that says Pluto is not a planet is not useful because scientists are not using it in their publications. But the definition that has existed since the time of Galileo, the one that most planetary scientists actually use, is very useful, and we use it in our publications all the time. That definition from Galileo says that the planet is a geologically complex body like the Earth is. Pluto is most definitely a geologically complex body, fully worthy of the term planet, as Galileo and Planeto Harry, scientists have used the word for the past five hundred years. Moreover, Metzger argues the IAU's definition of a planet actually was a step backward toward a pre scientific view of nature. He said, scientists discovered the solar system is messy, that planets don't all orbit the Sun, that they kick each other around and share orbits with other objects. The IAU definition tries to emphasize the organization of a solar system, saying planets are the small number of objects that rule in their orbits. It communicates the wrong idea that organization is the central truth about solar systems. In fact, for a planet to clear its orbit, the process is contingent, incomplete, and often temporary. A broadening or rebroadening the definition of planets would lead the way to including other objects like Aris, an object in the Kuiper Belt that's twenty five percent larger than Pluto. It was discovered in two thousand in five and prompted the debate that led to the IAU's redefinition. A Metzker said a problem with the two thousand and six definition is that people have lost interest in the discovery of planets. People think, well, they are just leftover junk like asteroids, though they're not important. As a result, the excitement is not taught in the classroom and the public doesn't pay attention. But they are actually amazing planets like Pluto and Shareon, and there are over one hundred and fifty of them, and there is plenty that's interesting about Pluto. How stuffworks also spoke via email with paper co author Kirby Runyan, a planetary geomorphologist at the Planetary Science Institute. He said Pluto has glaciers sliding down from the mountains. It has a multi layered atmosphere with climate cycles. It has mountains as big as the Rocky Mountains and they are currently being built up. It has an ancient ice lake with a shoreline. It has sublimation pits in the ice with fantastical patterns that suggest convection is happening under the ice. There's evidence of an underground ocean. There must be a heat source to keep that ocean liquid. There's even a possibility that life could exist in that ocean. There's still much to be learned about Pluto. The probe New Horizons did a fly by in twenty fifteen, but most of Pluto's southern hemisphere was shrouded in winter darkness at the time, and other regions were in low resolution, and the probe didn't include every possible piece of equipment. For example, if there is or was a subsurface liquid ocean, discovering a magnetic field around the planet would provide a solid clue, but would need to send a magnetometer on our next spacecraft to head that way. Beyond that, it's not known whether Pluto's features are unusual or representative of other small planets, Iranian said. For instance, are our most Huper Belt planets simple with just craters and fractures like the moons of Uranus or share On, or are they dynamic planets. Triton, we think, used to be a Kuiper Belt planet and is now a satellite planet orbiting Neptune. It also has rich and varied act of geology, like geysers, but of a different nature than Pluto. However, Metzger is not hopeful that the IAU will reconsider its decision. He said many of its members have become stubborn about it. This is why we aren't supposed to vote in science. Voting creates biases. Taxonomical classification is a part of science, so we should not allow biases to enter in. That is why it was a mistake to vote on the definition of a planet. It should have never happened. Today's episode is based on article Pluto is it a planet? After all? On how stuffworks dot Com? Written by Patrick J. Kiger. And Stuff is production of iHeartRadio in partnership with how stuffworks dot Com and is produced by Tyler Klang. Four more podcasts my heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.

Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff Lauren Vogelbaum here. Back in two thousand and six, to the puzzlement of many in the non scientific public and some astronomers as well, the International Astronomical Union decided to demote Pluto from its status as a full fledged planet. Instead, the IAU decided what had been considered the most distant of the nine planets in our Solar System actually belonged in a new category of dwarf planets. This category also includes Series, the largest object in the asteroid belt between Mars and Jupiter. The IAU's reasoning was that Pluto only had two of what they had decided were the three characteristics of a planet. That it is in orbit around the Sun, that it has sufficient mass for its self gravity to overcome rigid body forces and give it a nearly spherical shape. And that it has cleared the neighborhood around its orbit of other objects, a meaning that it's either collided with, captured, or driven away smaller objects nearby. Pluto flunked that last test because it shares its orbit with the Kuiper Belt, a sort of doughnut shaped disc of thousands of smaller icy objects beyond Neptune that Pluto has failed to clean up gravitationally speaking, the ii used decision, which was voted on by a very small percentage of the world's astronomers and planetary scientists, was a controversial one. After a debate in twenty fourteen among scientists sponsored by the Harvard Smithsonian Center for Astrophysics, the majority of the non expert audience voted for a simpler definition of planet, basically that it has to be spherical, an orbit around a star or the remnants of one. This definition included Pluto, and that audience aren't the only people who feel this way. In a paper published in the journal Icarus in February of twenty nineteen, a team of planetary scientists analyzed more than two centuries worth of scientific studies and found that, with the exception of one paper published in eighteen oh two by British astronomer Sir William Herschel, nobody talked about the non sharing of an orbit as a criterion for distinguishing planets from non planets. To the contrary, the researchers found that scientists routinely described what we now know to be asteroids as planets until the nineteen fifties, because that is when our instruments became sensitive enough to show that asteroids had geophysical differences, namely, they weren't massive enough to be rounded. The researchers wrote in the paper, We therefore conclude that the argument made during the IAU planet definition controversy that planet sized Kuiper Belt objects should be classified as non planets because they share orbits is arbit and not based on historical precedent before the article. This episode is based on how stuff Works. Spoke via email with paper co author Philip Metzger, a planetary scientist at the University of Central Florida. He explained that the ia used emotion of Pluto largely has been disregarded by planetary scientists. A quote in science, we classify objects in ways that are scientifically useful. The definition that says Pluto is not a planet is not useful because scientists are not using it in their publications. But the definition that has existed since the time of Galileo, the one that most planetary scientists actually use, is very useful, and we use it in our publications all the time. That definition from Galileo says that the planet is a geologically complex body like the Earth is. Pluto is most definitely a geologically complex body, fully worthy of the term planet, as Galileo and Planeto Harry, scientists have used the word for the past five hundred years. Moreover, Metzger argues the IAU's definition of a planet actually was a step backward toward a pre scientific view of nature. He said, scientists discovered the solar system is messy, that planets don't all orbit the Sun, that they kick each other around and share orbits with other objects. The IAU definition tries to emphasize the organization of a solar system, saying planets are the small number of objects that rule in their orbits. It communicates the wrong idea that organization is the central truth about solar systems. In fact, for a planet to clear its orbit, the process is contingent, incomplete, and often temporary. A broadening or rebroadening the definition of planets would lead the way to including other objects like Aris, an object in the Kuiper Belt that's twenty five percent larger than Pluto. It was discovered in two thousand in five and prompted the debate that led to the IAU's redefinition. A Metzker said a problem with the two thousand and six definition is that people have lost interest in the discovery of planets. People think, well, they are just leftover junk like asteroids, though they're not important. As a result, the excitement is not taught in the classroom and the public doesn't pay attention. But they are actually amazing planets like Pluto and Shareon, and there are over one hundred and fifty of them, and there is plenty that's interesting about Pluto. How stuffworks also spoke via email with paper co author Kirby Runyan, a planetary geomorphologist at the Planetary Science Institute. He said Pluto has glaciers sliding down from the mountains. It has a multi layered atmosphere with climate cycles. It has mountains as big as the Rocky Mountains and they are currently being built up. It has an ancient ice lake with a shoreline. It has sublimation pits in the ice with fantastical patterns that suggest convection is happening under the ice. There's evidence of an underground ocean. There must be a heat source to keep that ocean liquid. There's even a possibility that life could exist in that ocean. There's still much to be learned about Pluto. The probe New Horizons did a fly by in twenty fifteen, but most of Pluto's southern hemisphere was shrouded in winter darkness at the time, and other regions were in low resolution, and the probe didn't include every possible piece of equipment. For example, if there is or was a subsurface liquid ocean, discovering a magnetic field around the planet would provide a solid clue, but would need to send a magnetometer on our next spacecraft to head that way. Beyond that, it's not known whether Pluto's features are unusual or representative of other small planets, Iranian said. For instance, are our most Huper Belt planets simple with just craters and fractures like the moons of Uranus or share On, or are they dynamic planets. Triton, we think, used to be a Kuiper Belt planet and is now a satellite planet orbiting Neptune. It also has rich and varied act of geology, like geysers, but of a different nature than Pluto. However, Metzger is not hopeful that the IAU will reconsider its decision. He said many of its members have become stubborn about it. This is why we aren't supposed to vote in science. Voting creates biases. Taxonomical classification is a part of science, so we should not allow biases to enter in. That is why it was a mistake to vote on the definition of a planet. It should have never happened. Today's episode is based on article Pluto is it a planet? After all? On how stuffworks dot Com? Written by Patrick J. Kiger. And Stuff is production of iHeartRadio in partnership with how stuffworks dot Com and is produced by Tyler Klang. Four more podcasts my heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.