Comment on Sad Ganymede noises
JackbyDev@programming.dev 4 weeks ago
People fighting for Pluto that it should be a planet instead of a dwarf planet
Ceres: 🥺
Context: Ceres is now considered a dwarf planet, and used to be considered just an asteroid, but when it was first discovered it was considered a planet. That was in 1801. There is no objective criteria for what a planet is and isn’t. Like a lot of things in nature, things just exist, and as humans we categorize them. Ceres is round like a planet like Pluto. I’m not saying it should e considered a planet, I think dwarf planet fits them both nicely. As late as the 1950s Ceres was still sometimes considered a planet by some people.
I have a sort spot for it. I love it.
There is no objective criteria for what a planet is and isn’t
There are - exactly three.
- is in orbit around a star,
- has sufficient mass to assume hydrostatic equilibrium (a nearly round shape), and
- has “cleared the neighbourhood” around its orbit.
The last one means that its gravitational pull has removed any smaller objects that might be in its orbit, either by kicking them out of it, or by catching them as moons.
Pluto is barely round and its orbit is full of debris.
There is no objective criteria for what a planet is and isn’t. Like a lot of things in nature, things just exist, and as humans we categorize them.
You’re the second person to ignore the sentence immediately following that.
Because that sentence doesn’t really make sense. “Criteria” is a human concept. Nature doesn’t do “criteria”, nor “objective” for that matter. So, yes, there’s no “natural criteria” for when something is X or Y, we, humans, make those criteria. Doesn’t matter if it’s in relation to animals, plants, or planets.
So you’re saying things just exist, and as humans we categorize them? Because that’s what I said.
The scientific community was basically backed into a corner: either create a new category for Pluto and similar bodies, or we go from 9 planets to over 3,000 (iirc), lol.
The only sensible choice was made, imo.
I found it interesting that Warframe, set in the Solar System (+ SciFi/Fantasy stuff) features not only the various planets (including Pluto), but also moons (Deimos, Phobos, Europa) and dwarf planets (Ceres, Eris, Sedna) and even an asteroid (though the original name isn’t known, if it ever had one). Not relevant to the topic, just came to mind.
Most of my space knowledge comes from Elite Dangerous lol. They used a lot of real star catalogs when making the galaxy and visually it’s really good.
it blew my tiny mind when i found out that there are multiple dwarf planets in long solar orbits in our system
they might be small and enjoy solitude but why are we forgetting about them???
and now apparently there’s also a dwarf planet in the inner solar system that nobody talks about??? rude
there’s also a dwarf planet in the inner solar system
It’s arguable about whether it’s in the “Inner Solar System”. Ceres is inside the asteroid belt, and the asteroid belt is the separator between the inner and outer system. It’s like floating in the middle of The Rhine and debating whether you’re in Germany or France
Exactly! It’s right there past Mars! It’s not like it’s some weird thing off in the cold dark past Pluto.
There is no objective criteria for what a planet is and isn’t.
There is, though, or rather there should be another one.
The official definition says
But I also said,
Like a lot of things in nature, things just exist, and as humans we categorize them.
There is no objective criteria for what a planet is and isn’t.
There is, though, or rather there should be another one.
The official definition says it’s a planet if it’s big enough to be round, which IMHO is a bullshit definition because nobody cares whether your object’s round, as in, for practical settlement purposes.
What’s important though is that it’s large enough to hold an atmosphere (at least if it had one). That’s only the case if the gravitational field is strong enough, which is the case roughly for objects of mass starting at around 10^23 kg. That definition fits surprisingly well the current actual classification of what is a planet and what isn’t, though.
The official definition says it’s a planet if it’s big enough to be round, which IMHO is a bullshit definition because nobody cares whether your object’s round, as in, for practical settlement purposes.
That’s the second out of the three points of the definition.
As to why it’s not bullshit - the roundness is a byproduct of the object achieving hydrostatic equilibrium (which is the actual criterion, not roundness).
What’s important though is that it’s large enough to hold an atmosphere (at least if it had one).
Define an atmosphere. Because there’s multiple asteroids that technically have one, albeit extremely thin ones. And be careful about being too nitpicky, as Mercury’s atmosphere is just it’s rock being vaporized due to its proximity to the sun
Because there’s multiple asteroids that technically have one, albeit extremely thin ones.
can you please link an example?
And of course, scientists often just use the non-dimensional number characterizing this; gravitational scale height divided by the atmospheric scale height is the Gandolfi number (Gf). :-)
Gandolfi number (Gf). :-)
wait, fr?
No, and I screwed it up! Should have been the Gandalfi Number
HeyThisIsntTheYMCA@lemmy.world 4 weeks ago
I’m fighting for jupiter to also be a dwarf planet because it has not cleared its orbit of a few million asteroids.
rbos@lemmy.ca 4 weeks ago
All those asteroids are cqptured in Jupiter’s Trojan points, no?
HeyThisIsntTheYMCA@lemmy.world 4 weeks ago
You make a very adulterous point, Senator.
mnemonicmonkeys@sh.itjust.works 4 weeks ago
*Lagrange points
Gormadt@lemmy.blahaj.zone 4 weeks ago
Image
You do have a point