Chapter 11: Part 1

Pluto and the Dwarf

Planets

Pluto was discovered by Clyde Tombaugh in 1930 by comparing one image of the sky taken one night with an image taken 6 nights later.

Pluto: Ruler of the Underworld

The discovery of Charon

Charon and Pluto

HST discovers new moons!2012

• Strange object; located far out from the Sun with gas giants but small size and very elliptical and highly inclined orbit

• Pluto is a mixture of ices and rocks• composition similar to satellites of giant

planets • Could be captured Kuiper Belt Object (e.g.

comet)?

What is Pluto?

Pluto’s strange orbit

Quaoar, Sedna, Earth, Moon, and Pluto size comparisons

10th Planet???

A "planet" is a celestial body that: (a) is in orbit around a star, (b) has a nearly round shape (c) and has cleared the neighborhood around its orbit.

8 Planets !

IAU Definition

Planets sweep up all the material along their orbit

Pluto’s strange orbit

Dwarf Planet Orbits are Strange

A “dwarf planet is” a celestial body that: (a) is in orbit around the Sun, (b) has a nearly round shape (c) has not cleared the neighborhood around its orbit and is not a satellite

5+ Dwarf Planets !

Dwarf Planet Definition

New Horizons visits Pluto July 2015

Pluto revealed!

Pluto and Charon