Transcript Chapter 19-3

Chapter 19-3
Formation of the Solar System
(Solar System Simulator:
http://space.jpl.nasa.gov/ )
Successful models in science
Must account for and make
sense of observations
Do we Have a Viable Theory?
It must be
1. based on physical principles (conservation of
energy, momentum, the law of gravity, the law
of motions, etc.),
2. able to explain all (at least most) the observable
facts with reasonable accuracy, and
3. Able to explain other planetary systems.
Testing Our Theory against other solar systems
1. Can we find protoplanetary disks?
2. Can we find other solar system?
3. Does our theory explain the other solar system?
How do we go about finding the
answers?
1.Look for clues
2.Come up with some
explanations
3.See if our idea explains
everything (or most of it)
4.Try again: if it doesn’t quite
work, go back to step 2.
Clues – What does the solar system look like?
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Sun, 0 AU
Inner Planets
(Mercury, Venus,
Earth, Mars) ~ 1 AU
Asteroid Belt, ~ 3 AU
Outer Planets
(Jupiter, Saturn,
Neptune, Uranus), ~
5-40 AU
Kuiper Belt, ~ 30 to
50 AU
Oort Cloud, ~ 50,000
AU
NASA Figure
Cool link about solar system:
• http://liftoff.msfc.nasa.gov/academy/space/solarsystem/solarsystemjava.html
Clues - The Orbits of the Planets
• All the planets orbit the Sun in the same
direction
• The spin axes of most of the planets and the
Sun are roughly aligned with the rotation axes
of their orbits.
• Orientation of Venus, Uranus, and Pluto’s spin
axes are not similar to that of the Sun and
other planets.
Clues - What do they look like?
The Inner Planets
They are all…
• rocky and
small!
• No or few
moons
• No rings
Clues - The Jovian Planets
They are all…
• gaseous and
BIG!
• Rings
• Many moons
How did the solar system form?
National Geographic’s Naked Science:
“Birth of the Solar System” – sun, fusion,
nucleosynthesis
University of California: “Order from
Chaos: The Birth of the Solar System”
Other Solar Systems
As of this date, ___ planets
have been discovered.
2 (1996)
4
6
31
61
96
117
121
161
209
271
332
374 (4/14/2010)
418 (4/27/2010)
“For then why may not every one of these Stars or
Suns have as great a Retinue as our Sun, of planets,
with their moons, to wait upon them? Nay, there’s
Manifest reason why they should.” Physicist
Christiaan Huygens, 1698
“There are countless suns and countless earths all
rotating around their suns in exactly the same way as
the seven planets of our system . . . The countless
worlds in the universe are no worse and no less
inhabited than our Earth.” Giordano Bruno, 1584;
burned at the stake for heresy
•Oldest known:
PSR B1620-26c (13 billion years)
•First Discovered:
51 Pegasi b (1996)
•Largest core:
HD 149026 b
•Most distant found:
OGLE-2005-BLG-390Lb (21,500 light years)
•May have liquid water:
Gliese 581 c
•Largest diameter:
TrES-4
•Smallest found:
Gliese 436 c