Podcast Summary
Planet reclassification: In 2006, the International Astronomical Union redefined a planet as an object that orbits the sun, is spherical in shape, and has cleared its orbit of other debris, leading to Pluto's reclassification as a dwarf planet.
The definition of a planet in our solar system was redefined in 2006 at a meeting in Prague by the International Astronomical Union (IAU). Prior to this, Pluto was considered a planet. However, after the meeting, Pluto was reclassified as a dwarf planet due to it not meeting the new criteria for a planet. The IAU decided that for an object to be considered a planet, it must orbit the sun, be spherical in shape, and have cleared its orbit of other debris. This decision was made after the discovery of multiple objects similar in size to Pluto. Virginia Trimble, an astronomer and historian of science, was present at the meeting and helped count the votes. The meeting resulted in a significant change in the way we classify celestial bodies in our solar system. This discussion also highlighted the importance of scientific meetings and the collaborative effort it takes to redefine scientific concepts.
Planet definition controversy: The definition of a planet was changed in 2006, resulting in Pluto's demotion due to its failure to clear its orbit of other celestial bodies, causing controversy within the scientific community
The definition of a planet was redefined in 2006, leading to the demotion of Pluto. To be considered a planet, an object must orbit the sun, be large enough to assume hydrostatic equilibrium, and clear its neighborhood of other celestial bodies. Pluto did not meet the third requirement, leading to controversy within the scientific community. This decision was made primarily by astronomers, not planetary scientists, which was a point of criticism. Despite this, some planetary scientists continue to defend Pluto and view it as a valuable object for studying the formation of planets.
Planet definition evolution: New discoveries led to redefining a planet from a moving celestial body larger than an asteroid to a celestial body that orbits the sun, is spherical, and has cleared its orbit of other debris.
The definition of a planet has evolved over time based on new discoveries in our solar system. This was exemplified by the demotion of Pluto from a planet to a dwarf planet. In the early 1800s, scientists were searching for a planet between Mars and Jupiter and discovered Ceres. However, they found many objects in the asteroid belt, leading to a rethinking of what these minor planets were and eventually being called asteroids. Pluto, discovered in 1830, was always considered an oddball due to its location in the outer solar system near the Kuiper Belt. When astronomers discovered the more massive dwarf planet Eris in the same region, they had to redefine what a planet was or risk having countless objects being classified as planets. Pluto, despite its fascinating history and potential clues to planet formation, no longer fits the current definition.
Planetesimos formation: Smaller dust grains in a disc of gas and dust coalesce and grow larger, forming the first building blocks of planets called planetesimos. Gravity takes over and they continue to grow, potentially attracting gas from the disc and forming larger planets. Massive planets can prevent smaller bodies from colliding and growing into larger planets by causing orbital instability and fragmentation.
Planets and dwarf planets like Pluto form from a disc of gas and dust in space. This disc contains smaller dust grains that eventually coalesce and grow larger, forming the first building blocks of planets called planetesimos. Asteroids and comets are examples of these planetesimos. Once these building blocks reach a certain size, gravity takes over and they continue to grow, potentially attracting gas from the disc and forming larger planets like Earth or even gas giants like Jupiter. However, the presence of massive planets like Jupiter in the solar system can prevent smaller bodies from colliding and growing into larger planets, as the gravitational forces of these massive planets can cause orbital instability and fragmentation instead. For instance, the asteroid belt between Mars and Jupiter did not become a planet due to Jupiter's influence.
Asteroid belt and Pluto's development: Jupiter's massive size prevented asteroids from coalescing into a planet in the asteroid belt, while Pluto didn't form in its current location but was put into orbit by Neptune. The IAU and some astronomers have different definitions of a planet.
The asteroid belt did not turn into a planet due to Jupiter's immense size and gravitational pull, causing asteroids to collide and shatter instead of coalescing. The Kuiper Belt, where Pluto resides, has a much lower density of objects, making it unlikely for them to grow large. Pluto, being a large body, did not form in its current location but was put into orbit by Neptune. The International Astronomy Union (IAU) definition of a planet includes orbiting the sun, being round, and clearing its path. However, some astronomers propose a geophysical definition of a planet based on mass alone, making an object round if it has enough mass. If Pluto were placed in Mercury's orbit, it would clear the orbit and, therefore, be considered a planet under this definition. Overall, the size, location, and mass of celestial bodies play significant roles in their development into planets.
Planetary definition: Planets are defined as objects with enough mass to be round but not fusing from the inside, while the definition is debated and can include Pluto and Europa as planets under a geophysical definition
The definition of a planet can be categorized based on mass, with planets being objects that have enough mass to be round but not fusing from the inside, while rocks and asteroids are less massive. Pluto, which was previously considered a planet but then demoted due to its orbit not clearing other objects, would be considered a planet under a purely geophysical definition. This definition has been a subject of debate, with some concerns being raised about the potential for an overload of planets to remember. However, Europa, one of Jupiter's moons, is an example of an object that, if placed in an independent orbit around the sun, would be considered a planet. The International Astronomical Union (IAU) held a vote in 2006 regarding the planetary definition, and while the outcome remains, some scientists advocate for a geophysical definition that would include Pluto as a planet. Ultimately, the number of planets does not pose a significant issue for memory or understanding, as the distinction between planets, moons, and other celestial bodies is based on their unique characteristics.
Pluto exploration, Betelgeuse: Pluto explores stars beyond our solar system, like Betelgeuse, a red supergiant believed to be on the brink of explosion, while listeners learn about technology's impact on the body through NPR's Body Electric Challenge.
Pluto, a topic of excitement on the Space Camp podcast, is venturing beyond our solar system to explore stars like Betelgeuse, a red supergiant believed to be on the verge of explosion. The podcast, produced by NPR, is brought to listeners by sponsors Planet Oat and Mint Mobile. While the team explores the cosmos, listeners can participate in NPR's Body Electric Challenge, learning about the impact of technology on the body. The podcast is led by Regina Barber, with contributions from experts like Doctor Seraphina Nance and a dedicated team. Betelgeuse's impending explosion is a reminder of the wonders of the universe and the endless opportunities for discovery.