The man who discovered Eris, astronomer Mike Brown, told National Geographic last year that the question came down to orbits: "Why has the solar system sorted itself into a small number of dominant bodies and a huge number of tiny ones flitting between them?
Some astronomers even openly consider very large moons like Ganymede and the Moon planets as well and have posed the question (in Stern's words) "If stars can orbit stars, why can't planets orbit planets?" Regardless of where you come down on the nomenclature, Pluto and its moons represent a very exciting system of worlds that has never been explored.
Actually, that is not the way satellite orbits work but why should a dreary matter of fact stand in the way of a good miserabilist image?
Rocky planets, which have managed to coalesce, settle eventually into more or less stable orbits, explaining why planetary systems are generally packed to the limit; or, in other words, why they always appear to be at the brink of instability.
It's easy for people who aren't science- fiction enthusiasts to laugh at the genre — its earnestness, its lingo, its fans' awestruck romance with the idea that God is in the details of equipment and uniforms and security codes and how many moons orbit Planet X and why it's called Planet X in the first place.
By Nancy Franklin It's easy for people who aren't science- fiction enthusiasts to laugh at the genre its earnestness, its lingo, its fans' awestruck romance with the idea that God is in the details of equipment and uniforms and security codes and how many moons orbit Planet X and why it's called Planet X in the first place.
However, the Moon doesn't have enough gravity to retain particles in orbit – that's why there's no atmosphere.
Both groups are proposing similar spacecraft to orbit Mars and study why the planet's thin atmosphere is escaping into space.
She says the simulations show that this kind of orbit flipping may explain why nearly half of the hot Jupiters seen so far have retrograde orbits.
The most puzzling aspect of Sedna is why its orbit is now so eccentric, says planetary scientist Eugene Chiang of the University of California, Berkeley.
