Why Pluto isn't a Planet Anymore

[@adamrushworth4372]

I wish I’d had you as one of my science teachers when I was still in school, your videos are amazing and I’ve always had a massive interest in all sciences! I hope these videos reach your students and that at least some of them go on to study sciences from your teachings! Keep up the fantastic and brilliant work mate

[@KaiAlanaFL]

So educational. I feel a little smarter with each of your video. # keep creating ;)

[@LearningCurveScience]

Thank you, I certainly aim to.

[@ObservationofLimits]

It's crazy to think back when we were still using muskets we were also proving (what I consider) incredibly precise measuring (planetary wobble) and complex maths by hand.

[@rowanrobinson]

Why does this only have 855 views? Great stuff

[@gth042]

It has not yet cleared its neighborhood of clickbait and fluff.

[@Daviticus042]

Almost 3000 now.

[@thevikingbear2343]

Because Pluto IS a Planet.

[@TheScottbb1]

@@gth042picking up more space dust with my recent subscription 👍

[@Soupy_loopy]

This is exactly why I don't consider small dogs to be real dogs!

[@LisaAnn777]

Yeah there dwarf dogs!

[@f.u.m.o.5669]

That's not how taxonomy works. Think of rocks, would you call a a rock that is, for example, that is 7 centimeters, a boulder? Probably not, we position should come up with a new name for this sized rock. Most would call that a pebble, not a boulder, a mountain with this analogy would a star.

[@Jellyman1129]

@@f.u.m.o.5669Yes, but they’re ALL still rocks, regardless of size. How can you claim a dwarf planet is not a planet?

[@marktorch9079]

I heard that further out from Pluto's orbit we find other Ice bodies relatively the same size. In fact their actually in abundance out there.

[@Jellyman1129]

There’s over 100 dwarf planets, possibly even more!

[@beverleycadel9917]

This is so interesting.

[@LearningCurveScience]

Thank you Bryany, glad you enjoyed it!

[@mysterycrumble]

i simply adore the little douglas adams references

[@LearningCurveScience]

Yes I'm a big fan, you'll find plenty of Doctor Who and Hitchhikers references throughout my videos.

[@joshuagorham5130]

Vid idea: Talk about Altair, a fast-spinning F-Type Star

[@PizzaPowerXYZ]

2:50 I was not expecting this

[@Jellyman1129]

Jump-scare! 😂

[@Dandroid_1]

It might not technically be a planet.... but it's still a planet in our hearts.

[@Jellyman1129]

Experts still call it a planet.

[@mikkokivisto4414]

I wonder what Tombaugh would've thought.

[@Jellyman1129]

If he was able to see his planet, he would’ve been amazed! His kids certainly were!

[@SureBetter]

This bothers me way more than it should. So now…my very excellent mother just served us nine…what? Nine what? Why can’t Pluto be grandfathered in with the Planet list? Rant over… as you were!

[@Jellyman1129]

The problem is that the definition is based on location, not physical characteristics. So it gives inconsistent results. The geophysical planet definition is superior in every way.

[@christophercharles9645]

It'd be neat if we could have a satellite stationed permanently around Pluto to see if (and by how many) objects it is impacted and interacts with. Seeing as it spends so much of its orbit plowing through the Kuiper Belt, it must see many more objects than we inner-solar system planets do. Whether it is considered a planet or not, it's still a fascinating object and it would be great to get more missions out there to it.

[@Jellyman1129]

The Kuiper Belt is so vast that Pluto doesn’t come into contact with any Kuiper Belt objects. They’re just too spread out. That’s why New Horizons had a hard time finding Arrokoth.

[@MrLince-hr4of]

ask Jerry😁

[@Jellyman1129]

“Pluto was a planet, some committee of fancy buttholes disagreed, I disagreed back!”

[@innertubez]

Pluto will always be a planet to me. Just being sentimental lol.

[@LearningCurveScience]

After making this video, I have a soft spot for Pluto too

[@Daviticus042]

I like it too, but I appreciate it for what it is.

[@Jellyman1129]

There are indeed scientific reasons to call Pluto a planet.

[@APopov]

Eris diameter is 2326 km while Pluto's is 2376 km. They are roughly of the same size. Eris is somewhat more massive, though. I knew Eris was larger than Pluto, had to double check the numbers. It is more massive while sizes are almost identical.

[@thevikingbear2343]

Eris is the cause of all the conflict. The Goddess of Discord strikes again.

[@Jellyman1129]

Eris is slightly more massive because it contains more rock than ice, but Pluto is larger by volume.

[@brammers98]

Are you from Bolton?

[@bazpearce9993]

I am. It's close to a Bolton accent, but not quite. Still sounds fairly local though. Maybe South Manchester.

[@destroyingangel14]

Kieper belt ( sp?)... must be passed through in order to reach other Solar System.... because space ship will need to utilize plane ... on which planets are rotating ..in order to use large body gravitational force. How much is the plane deviated from by other planets...?

[@Daviticus042]

*Kuiper

[@Orion2525]

The last Planet criteria is rubbish, pardon my pun. It means that if the orbit of Pluto changed to inside Neptune, it would be a planet. So what is and what is not a planet is partially based on its location rather than physical characteristics alone.

[@Daviticus042]

What pun?

[@f.u.m.o.5669]

If Pluto Mas more massive, It would of pulled in much of the matter of the Kuiper belt into it, and therefore would be considered a planet. It didn't. Very simple stuff here, mate, the video literally explained it. Stop trying to act like scientists have no idea what they are saying, then have multiple years in the subject, and I assume you don't.

[@thevikingbear2343]

Is Mercury a Planet? If Mercury's Orbit was were Pluto is, it would not be a Planet based on the third criteria.

[@f.u.m.o.5669]

@@thevikingbear2343 Mercury is large enough to absorb the particles in the Kuiper belt, and probably would probably collide with Neptune due to its size. Please, just actually bring up actual valid points, please. I'm literally begging you.

[@Jellyman1129]

@@f.u.m.o.5669I guess rogue planets aren’t planets then. They don’t have an orbit.

[@farmergiles1065]

You describe well the reasons the IAU gives for "demoting" Pluto. But really, I question the IAU's reasons. Was politics the real reason? Well, there was politics in the IAU, rapidly expanding to the world. But that's not the argument I want to make. I've always found the third criterion - "must clear its orbit" - to be suspect. That's not at all as fundamental to the body as the fact that it has sufficient mass - therefore gravity - to make its shape round. The shape is inarguable, self-evident, and requires no judgement call such as "when is an orbit cleared?". No artificially-established rules to be monitored! While Pluto clearly hasn't cleared its orbit, isn't it also true that Neptune hasn't cleared its orbit? After all, Pluto freely crosses Neptune's orbit without being dominated by Neptune. And if Neptune were at some future time to kick Pluto out of its orbit, or capture it as a moon, does that then mean Neptune then - and only then - gets to be a planet? And why, really? This rule just seems arbitrary, as well as argumentative. (And it only got 60% of the vote - hardly a scientific measure of confirmation.) But a physicist I recently encountered asked another question that I find intriguing: "What's the big deal about a planet orbiting the sun?" Does that apply only to our own star? No, couldn't be: too ridiculous. So a planet orbits its own star. What if it exists in a binary, ternary, or even larger stellar system? Does it mark "its own" star by orbiting it - and not the others? But what if it orbits two stars? Seems ok for a binary system, but what if that's two stars out of three in a ternary system? Etc, etc? Finally, if something happens to destabilize an entire system and a planet is thrown entirely out of orbit into the void, is it still a planet? Again, this characteristic seems arbitrary. The only real requirement I can see for being a planet is that it's big enough to be round! That's the thing that applies everywhere, all the time, to any individual celestial body, *that is inherent in the planet itself* , and not dependent on something else to characterize it. I think the IAU made a big mistake. Instead, after making roundness the single defining feature, I see the other features (perhaps) as a means to classifying sub-categories of planets. (Level 1 [orbits]. Subcategories: Orbits one star, orbits two, orbits three, orbits all stars in system, or not. Level 1 [domination] Subcategories: Dominates its orbit, or not.) And why stop there? Why are some moons not also planets? Why does the orbit have to be around a star? Why does there need to be an orbit at all? Do we have any proof there are no "rogue planets" out in interstellar or intergalactic space? And given the operations of black holes in the universe, how could there not be? If the body is round, it's basically a world. If a person lands on it, there is gravity enough to hold a person there, a horizon to look over, a sense of distance to dwarf the person and become perceptually an environment. And if there's too much gravity, or no solid surface to land, any approach will clearly be an approach to a world, and likely a very exciting environment. So round moons are a subcategory of planet. And if there are any such, a round moon of a moon a subcategory of that. And Phobos and Deimos ought to take their proper classifications as asteroids orbiting a planet, leaving moons properly classified as planets that orbit a planet (therefore round). When I look up at our wonderful planet-moon, it irks that such a particle as Phobos could be called a moon also! Consider the 145 moons of Saturn (a number that grows by leaps and bounds)! Some are worlds, and some (many) are asteroids. Its orbital companions are already divided by scientists into three categories: "major moons", "prograde moons" (orbit in the direction of Saturn's rotation), and "retrograde moons" (retrograde orbit). Those categories are used to assign moon names from one of three groupings of names selected because of those characteristics. The IAU's system is out of date already. Finally, I *do object* to one demotion: that is the diminishment of respect that is due to Clyde Tombaugh, discoverer of Pluto. That was first-rate science as well as luck, and years of painstaking, meticulous work. Pluto still is what Pluto always was, and his fame should rightfully continue.

[@Jellyman1129]

This deserves an award. This is the BEST comment about this topic I’ve ever seen! Yes, politics was a large factor in demoting Pluto. Some astronomers (particularly dynamicists like Brian Marsden) had an agenda against Clyde Tombaugh and tried to erase his legacy. There was clearly an anti-American sentiment at the meeting and it’s a shame that politics interfered with science. The actual data from planetary science got lost in the shuffle of emotional yelling and arguing. The third criterion was specifically engineered to exclude the dwarf planets. It’s vague because technically NONE of the planets have a cleared orbit, and the IAU wanted to be as ambiguous and sly as possible to arbitrarily separate the dwarf planets from the other planets. It’s very clearly contrived. It’s absolutely a botched mess when 2% of the IAU voted for this definition, another 2% voted against it (nearly split down the middle), and the remaining 96% didn’t even know this vote was happening! It was rushed, underhanded, and deceitful with a tiny sample size, done purely to get the vote to sway in the dynamicists’ favor. Some IAU members who were unaware of the vote felt so betrayed that they resigned and left the union, knowing political meddling was afoot. Also, when do we ever vote in science?! Voting is just not a scientific method for reaching a conclusion. The vote has no scientific data or precedent to validate the decision, making it bogus and non-binding. It’s opinion, not fact. The IAU specifically wanted to define a planet in OUR solar system and purposely didn’t address extrasolar planets. So by the first criterion saying a planet must “orbit the Sun”, they really mean THE SUN. Why make a definition for something that only works for OUR solar system and not every other system in the galaxy?! So as it stands, no extrasolar planet is a planet since it doesn’t orbit THE SUN. And rogue planets used to orbit a star, but got ejected from their system. Do they cease to be planets? Are brown dwarfs planets or stars? All of these questions are left unanswered in the nonsensical IAU definition. A round shape is the defining attribute of a planet. You cannot have a planet that isn’t spherical. And it’s intrinsic to the object, not dependent on external situational factors like orbit or location. Planetary scientists unanimously rejected the IAU vote immediately after it was made. They use the geophysical planet definition, which says if an object is in hydrostatic equilibrium (a spherical shape), but isn’t doing thermonuclear fusion (like a star), it’s a planet. Short and simple. It’s often called the Star Trek test. If the audience sees an object like Saturn or Pluto or Titan or Kepler-22 b or Makemake or Europa on the viewfinder of the Starship Enterprise, everyone on the crew and everyone watching the episode immediately knows “That’s a planet”, without having to say “Hmm, let me survey the entire solar system for all objects that are here so I can integrate their orbits to determine which ones have successfully cleared their neighborhoods, I’ll get back to you in the morning.” Nobody needs to do any dynamical calculations to determine which objects are planets. It’s a simple “I-know-it-when-I-see-it” mentality. The IAU made a huge mistake and they know it. Subcategories of planets are very useful and planetary experts already have dozens of them under the geophysical planet definition. Planets that orbit the Sun (like Earth) are called solar planets. Planets that orbit a star other than the Sun (like Kepler-186 f) are called extrasolar planets. Planets that orbit other planets as moons (like Titan) are called satellite planets. Planets that orbit another planet with the barycenter between both bodies (like Pluto and Charon) are called binary planets. Planets that orbit pulsars (like Dragur) are called pulsar planets. Planets that orbit black holes are called black hole planets. Planets that orbit nothing are called rogue planets. Planets that are rocky are called terrestrial planets. Planets that are big and gaseous are called (gas) giant planets. Planets that are small and icy are called (ice) dwarf planets (which are full-fledged planets under this classification system). “Dwarf planet” was initially coined to mean “small planet” before the IAU misused the term for something completely different. But dwarf stars are stars and dwarf galaxies are galaxies. So dwarf planets are planets. Then you got other categories like hot jupiters with tails of evaporating gas, super earths larger than our planet, mini neptunes with icy interiors, puffball planets with incredibly low densities, hycean planets covered in water, and many more. So there are different subcategories that experts use, but they’re ALL still PLANETS, just different types. Phobos and Deimos are asteroids, in addition to being moons. “Moon” just means satellite, so they’re called satellite asteroids (or minor moons). Earth’s moon (Luna) is a satellite planet (or a major moon). Mars may have captured Phobos and Deimos from the Asteroid Belt. Triton is definitely a captured planet that Neptune grabbed from the Kuiper Belt. “Moon” is still a fine term to call satellite asteroids like Phobos and Deimos, but they’re minor moons. This keeps them separated from major moons like Ganymede and Enceladus. Then you have prograde moons and retrograde moons that further describe them. The IAU’s system was outdated from the start. We already knew of hundreds of exoplanets back in 2006 and they still chose to limit the definition to planets orbiting THE SUN. On top of that, they refuse to add any new dwarf planets that have been continually discovered over the last 15 years for some dumb reason. You final point…is beautiful. It’s the best way to end this already amazing comment: honoring the legacy of Clyde Tombaugh. Some people tried to erase his legacy, but I won’t let that happen. I won’t stand for it. He was an American hero and pioneered the discovery of the Kuiper Belt for later scientists like Gerard Kuiper to follow suit. He’s the first person to visit his planet, with his ashes onboard New Horizons, and his living son and daughter couldn’t be more proud. His fame shall continue and his historic contribution to astronomy shall absolutely be revered with the upmost respect. It’s hard to find people who appreciate his work, so thank you immensely for recognizing it. Your comment is flawless. It’s the most educated, eloquent, and scientifically respectful comment I’ve ever seen about this topic. Incredible job! I can’t give this enough likes! Bravo! 👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻 👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻 🏆🥇🏅🎖️

[@farmergiles1065]

@@Jellyman1129 You quite stun me! But I just had to write the comment. It comes not only from the mind but from the heart.

[@Jellyman1129]

@@farmergiles1065 I stun you? I don’t exactly know how, but thanks! Some of the best science comes from both the mind and the heart. I had to reply after reading a comment this fantastic!

[@farmergiles1065]

@@Jellyman1129 I'm stunned by the level of your praise, but I thank you kindly. And I agree that the best science comes from mind and heart. Only a whole person can assemble and organize understanding, perspective, and insight from the mass of picayune gathered facts from research, and find a way to communicate what it means. One can't argue with facts (which have no voice), but when they are interpreted honestly and without distortion, then you begin to find out what you know, and also what you don't know. Done right, it's a marvelous thing!

[@Jellyman1129]

@@farmergiles1065 It’s a topic I’m very passionate about and you’re one of the only people who actually mentions the legacy of Clyde Tombaugh. He’s usually a non-factor when most people bring up this debate, but I’m glad you included him. I think Alan Stern has done an incredible job with communicating New Horizons to the public and showing the more emotional side of science. It’s easily my favorite mission and is the first time I saw anything like this. I wasn’t born for Pioneer or Voyager or Viking. I saw Curiosity and Cassini and those are great, but New Horizons is in a league of its own. That mission literally changed lives.

[@nobody-nw8ut]

😊😊

[@denissavgir2881]

Hehe.. Skywalker, Vader, Leia crators 😄

[@thevikingbear2343]

Pluto is a planet because it has a Sailor Guardian. That is the most scientifically accurate way to differentiate a planet.