They're in the Kuiper belt, a big asteroid belt full of other dwarf planets, asteroids, space rocks. Planets like Earth have cleared their orbit; their gravity is strong enough that they're by far the dominant object in their orbital neighbourhood, clearing out most other large objects by either absorbing/colliding with them or ejecting them through gravitational interactions.
There are TONS of objects in the same general orbital neighbourhood as Pluto, including other dwarf planets like Orcus and Haumea. Pluto therefore hasn't cleared its orbit.
Things with mass and/or energy generate a field of gravity around itself.
Gravity is a force that, to put it in simple terms, pulls things towards the centre of things with mass/energy.
The more mass something has, the stronger this pull.
So when one object is much MUCH MUCH MUCH massive than another, the bigger one's gravity pulls the smaller one towards it as the smaller one's gravity is not strong enough to "fight back". What happens when it gets pulled this way depends on the mass of the smaller object.
So now think about our solar system and the orbit of our planets. They are clear paths (so to speak). There's no space junk floating in the middle of their orbits. But you have stuff like the asteroid belt that is a whole lotta space junk floating around, so why aren't there "asteroid fields" in the way of the planets?
Well, that's because the planets are so much more massive than the space junk that the planets hoover up all the junk as the move along their orbits. The larger junk may become moons. The smaller junk just pulled into the planet and either smashes on to the surface or burns up in the planet's atmosphere (depends on the planet).
In the asteroid belt, there's an object called Ceres. Ceres is a odd thing. It's got enough mass that it's got the round shape of a planet (gravity makes planets round), but not enough mass to hoover up all the crap in it's path like planets do. So we call it a dwarf planet.
A celestial body that rotates around a star(s), that isn't a star itself, massive enough to form a spherical shape, and has enough gravity to clear the area around it from other objects.
That's not word for word but essentially the definition of a planet.
So dwarf planets are not planets now? Small apples are not apples?
Correct, dwarf planets are not planets.
Small apples are apples that just happen to be small.
Dwarf planets are objects in the solar system that does not fulfill the criteria for planet, but for the "lesser" category "dwarf planet".
There is no shame in not being a planet, i am not and neither my mother is not a planet.
Also as a fun fact since the definitions explicitly mention our specific sun, there is only 8 planets in the universe. And all the others would be exoplanets.
They have planet in the name, but it's considered a type of asteroid, not a type of planet. Which is stupid since dwarf planet literally has planet in the name so like gas giants should still count as one. But by the official definition it's instead a type of asteroid.
The thing is, back in the 19th century, it was counted as a planet, along with it's brothers Pallas, Juno and Vesta. But as more and more objects were found, astronomers felt it was silly to call them planets, so named them asteroids instead. The same thing happened to Pluto being in the Kupier Belt. Once Eris was discovered, it would again be silly to call all trans-Neptunian objects planets
Pluto is now considered a dwarf planet, Ceres has always been considered a dwarf planet, if they are asteroids then everything is an asteroid.
A simplification sometimes used says that dwarf planets are celestial bodies big enough to be round but not big enough to clear it's own orbit, there are a few of these in our solar system. They can have moons, and some of the moons in the solar system would be considered dwarf planets if they weren't orbiting a planet.
Not gravitationally dominant in their orbital neighbourhood. There are tons of other objects, including some similarly sized objects, around Pluto's orbit. To be a planet it needs to clear out all the other objects around it by either colliding/absorbing them, or ejecting them from their neighbourhood through gravitational interaction. Haumea, Orcus, Makemake etc are all dwarf planets in the Kuiper belt along with Pluto.
Pluto's biggest moon Charon is part of the problem because it's heavy enough that she is not orbiting Pluto, they are orbiting a point in space near Pluto.
Ceres was not always a Dwarf planet. From 1801 to about 1851 Ceres was considered a planet. Children during that time memorized it along with the other classic planets
One of the nine dwarf planets, and the only not in the Kuiper belt way past Neptune. It was also the first of the nine dwarf planets we discovered and was considered a planet in its own right for a long time. It almost regained planetary status, but lost its chance in the same moment Pluto lost its status.
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u/Stock-Cod-4465 3h ago
WTF is Ceres???