Pluto is not larger than Mercury; Besides, that's not all that constitutes a planet.Originally Posted by The Ceej
I believe Pluto is larger than Mercury. Isn't Mercury still a planet?
A planet is defined as a celestial object that:
1) has sufficient mass as to overcome rigid body forces such that it becomes somewhat spherical.
Pluto actually has accomplished this as it is spherical.
2) has "cleared the neighbourhood" , meaning that its orbit is not interfered by other objects. All major planets in the solar system do not interfere with other celestial objects. Pluto however crosses paths with various objects, like the Kupier belt
Consequently Pluto is a dwarf planet, like the dwarf planet Ceres which sits happily between Mars and Jupiter, in the comet belt.
What's funny is that a dwarf planet by the name of Eris is actually bigger than Pluto and not found until 5 years ago (2003). Also the definition of a planet has changed. The proper definition has been in use since 2006.
Remind me again what year your textbook was? Shouldn't you update to a more recent book? I don't use textbooks from the 1700s when I want to learn about things. You shouldn't use books from the 1980s.
Nitpick: a planet ceases to be a planet if it gets to be a certain size: specifically when Nuclear fusion starts to happenBut yeah long story short the presence of orbital bodies does not qualify something as a planet cf. The Sun.
