Transcript Pluto & the Kuiper Belt

What happened to Pluto?
What happened to Pluto?
What happened to Pluto?
What happened to Pluto?
What happened to Pluto?
What happened to Pluto?
What happened to Pluto?
What happened to Pluto?
What happened to Pluto?
What happened to Pluto?
What happened to Pluto?
What happened to Pluto?
What
do we know of Pluto?
Are there objects farther away?
Why is Pluto no longer a “planet”?
What happened to Pluto?
What do we know of Pluto?
Tiny! (Smaller than 7 large moons)
 Density ~ 2 gm/cm3 (like Triton)
 One large tidally-locked moon, Charon
 4+ small moons

What do we know of Pluto’s system?
What do we know of Pluto’s system?
What do we know of Pluto’s system?
Not Terrestrial, Not Jovian

“Weird” orbit - more elliptical, inclined
Not Terrestrial, Not Jovian

“Weird” orbit - more elliptical, inclined

Very small
0.2% of Earth’s mass
 losing its atmosphere


Solid, icy, cold
A THIRD class of Planet – icy dwarfs?
Beyond Pluto

Eris (2003/2005)
37 to 97 AU, very elliptical
(~ 3 times farther away than Pluto)
 27% larger than Pluto
 One moon (“Dysnomia”)

Beyond Pluto

2003 EL61 “Haumea”
Two moons
 Elliptical
 Tumbles in 4 hours

Beyond Pluto

Quaoar (2002)
½ size of Pluto
 2x farther

Beyond Pluto

Makemake (2005)
Beyond Pluto
and even farther…

Sedna (2004)
extremely elliptical
orbit
 perhaps a new class
altogether?

What defines a planet?
History? (the “nine” traditional planets)
 Size? (existing + anything larger than pluto)



Roundness? (then Ceres, an asteroid, is too!)
Having Moons? (asteroids do!)
or
Classification by “population” – groups of similar or
unique objects
What defines a planet?

Populations:





Comets (Oort Cloud)
Inner Oort Cloud objects (?) - Sedna
Kuiper Belt objects – Pluto/Charon, Eris, Quaoar…
Asteroids
Individual objects

- Mercury to Neptune
But where do you put the Moon? Triton? Ganymede? Titan?
Science is alive, changing, adapting!
Lots of smaller bodies…
Exploring Pluto

New Horizons
2015 Arrival
 Challenges:

light (1/1500th Earth light)
 slow data rates (300 bps)
 dim
On the way to Pluto
New Horizons images from early 2007 on the way to Pluto…
On the way to the stars…