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irbinator OP t1_j3k0kmx wrote

Reply to comment by farmerarmor in TIL Pluto hasn't completed an orbit around the sun since its discovery. Pluto's orbit takes about 248 years, and Pluto was discovered in 1930. by irbinator

Right now I'm reading Dr. Mike Brown's book How I Killed Pluto And Why It Had It Coming. Only a couple of pages in, but so far it's been an interesting read.

Basically, he had discovered a new possible planet (Eris, aka Xena), and his discovery led scientists to finally formally define a planet for the first time. The new definition re-categorized Pluto and Eris as dwarf planets. Humbly, Dr. Brown was satisfied with that conclusion.

The book is what led me down this rabbit hole!

EDIT: Eris, not Ceres.

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GetsGold t1_j3kc4mu wrote

He discovered Eris, which was more massive than Pluto.

Ceres was a planet that was discovered between Earth and Mars and Jupiter in 1801. Around 50 years later after several more planets were discovered in that region they started referring to them as asteroids instead.

That's similar to what happened with Pluto. At first it seemed unique in its part of the Solar System, but by the 90's we started discovering many other objects in that region, another belt. So with Eris they decided to treat it like the asteroid belt and stop calling its members planets.

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irbinator OP t1_j3kfgei wrote

Ah, you’re completely right. Thanks! I always mix up Ceres and Eris. I’ll update my comment now.

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eveninglands t1_j3lslcb wrote

Pluto has the surface area roughly the size of Russia.

Now, Russia is pretty big, but it ain't no planet.

Bye bye, giant frozen ice rock that is not a planet, you shall not be missed!

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INTHEMIDSTOFLIONS t1_j3m8yhr wrote

Yeah, it was Eris, makemake, hamaeu, and a few others in 2005. They had the option to add 4 more planets, or they could re define what a planet was.

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10secondmessage t1_j3k2jfb wrote

You do know Roman's actually figured out Pluto before 1930. Just was observable till 1930

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irbinator OP t1_j3k2u45 wrote

I didn't, actually. Source?

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10secondmessage t1_j3k3yx3 wrote

Sorry, I think it was Greeks they did math and found grational forces outside of expectations, according to their limited data. They knew something else orbited out there just obviously couldn't prove it with telescopes. Which was the transfered to Pluto in Roman mythologies. If greeks/Roman's named planets how was Pluto named after this object?

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GetsGold t1_j3kcg0m wrote

They didn't have math at that level. You're describing how Neptune was discovered, but that was in the 1800s. It was found due to irregularities in the path of Uranus that would be explained by another planet.

Further discrepancies led to searching for another planet, and that led to finding Pluto. However Pluto was later found to be too small to explain them.

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10secondmessage t1_j3kds0k wrote

They used math well not as good as what we had. There are many asteroids that went of course due to what we now call Neptune and Pluto as the gravity it caused movements inconsistent with its path. Since they corectly guessed objects had no mass and traveled straight short of external forces such as gravity or transition of energy such as object acting to them selfs. This led to them thinking there were more plants based on this but could prove more than a gravitional force more likely planet based on planet behaviors they could observe. Like I said they knew about it but could say 100 what it was.

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GetsGold t1_j3kdztv wrote

They didn't even know about Neptune and almost certainly didn't know about Uranus even though it was technically just barely visible. They weren't making gravitational predictions about Pluto thousands of years ago when we couldn't even do that ourselves a hundred years ago.

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10secondmessage t1_j3kfn4s wrote

Like I said, they couldn't prove they were but estimated planets of other data. they had tools that would help them find objects such as Mars or a comet around Mars, etc. When in certain areas, there tools would be slightly off due to gravitational fields of large masses out beyond visible range. Well, the math was basic it proved there was what essentially was discovered. I'm not saying they had the tech or power that was used to conferm them like others later, only that in certain areas, masses existed and likely to be planets.

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GetsGold t1_j3kgeoa wrote

They did not predict the existence of Uranus, Neptune and Pluto thousands of years ago based on gravity. We couldn't even predict Pluto with modern equipment and math. You need some sources on this.

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10secondmessage t1_j3kizk7 wrote

Yes, they did when a commit is tracked for say a long time and their machine. https://en.m.wikipedia.org/wiki/Antikythera_Mechanism

Was off on predicting a comets path, which means they knew some new or force was being but on it. Considering greeks and Roman's had many scientist back then tracking things with similar results they estimate more planets or forces out there affecting a comets path, especially since the mass moved in the sky as disruptions were tracked as planets moved in their orbit.

This theory was still theory, but they knew more forces were out there. Because well not perfect as ours they had working orbit and trackable system. They were able to track and predict comets' paths with it when something moved a commit and no planet was around to have force on is how they realized other wandering masses must be out there. They knew there had to be other things affecting that they could observe things like this. So the theories were write just not provable. At there level of ablities.

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GetsGold t1_j3kjx66 wrote

So you're saying that they estimated comet paths but were off and so hypothesized the existence of other bodies or forces? Is there a quote in the article about that?

That's interesting, but not the same as predicting specific planets, and especially Pluto. Pluto is less than a fifth the mass of our moon and orbiting 30+ times the distance from the Sun as us. They wouldn't have close to the precise data to estimate that.

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AndrewTyeFighter t1_j3kwsxp wrote

They didn't even know how gravity worked back then and were just starting to consider that the Earth might not be the center of the universe.

They were not predicting planets that they couldnt see or comets paths based on gravity when they didnt even have the formulas and constants required to do such things.

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10secondmessage t1_j3kyr1q wrote

Yes, they did otherwise. How would they have made the first model of solar system it was wrong because gravity wasn't factored into it when the second model came out it traced orbits based on the concept of gravity, well the calculations were not hundred percent it still was close enough when you applied it in small numbers to find location of said item. Considering there limited tech and understanding it's amazing how well they did.

Second Ancient thinkers, from Aristotle in the West to Brahmagupta in the East, had theorised that objects were attracted to each other. Which is partially right as Newton would add direction(towards the centre) and give it mathemical representation/ gravitational force direction which change how the angle of force. Even though they math was off, they still had gravational force as a force of attraction espressesed as the orbital pathes of planets. The method was not perfect as it only counted gravational force, but that still put into their measurements and comparison.

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AndrewTyeFighter t1_j3l42ut wrote

Don't need to understand gravity to make a model of the observable solar system. Yet just because you make a model that is consistent with your observations, doesn't mean your model is correct.

The Antikythera Mechanism didn't model wasn't accurate because their understanding of the planetary model was incorrect. It also did not compute comets at all.

Aristotle thought that comets were atmospheric in nature, not bodies orbiting around the solar system, and on gravity he thought that everything was attracted to the Earth because it was the center of the universe, as well as that heavier objects would fall faster. These are not the basis for calculating the positions of undiscovered planets or gravitational disturbances of orbits of comets.

Your statements here are so wildly contradictory to history that I can only assume you are mistaken. If you really do feel you are correct, then please find some sources they actually back up your claims.

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Civil_Speed_8234 t1_j3l8fbt wrote

Planets up to Saturn were known to the ancient Greeks, but Uranus, Neptune and Pluto were named after the invention of the telescope (with the first one in 1781), and they just continued the naming convention in the same way. All the moons, dwarf planets, planetoids and other things in our solar system were named for Roman myths as well, but most of them weren't known until much more recently

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goodlittlesquid t1_j3ztgx6 wrote

Many of the more recently discovered dwarf planets are named after deities from other cultures. Haumea is Hawaiian, Makemake is Rapa Nui, Sedna is Inuit, Gonggong is Chinese. The moons of Uranus are named after English literary characters from Shakespeare and Alexander Pope.

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Civil_Speed_8234 t1_j40n7ns wrote

Thanks for adding this, I did know, but since it had nothing to do with the point I was making I failed to mention it

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Ahhhhrg t1_j3ln0fz wrote

You do know you’re talking absolute garbage? If you could actually back up your statement with a source (spoiler: there isn’t any) instead?

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