Title: Moons
1Moons
- The satellites of the solar system
2Moons of our solar system
- As of July 2009, there are 336 known natural
moons in our solar system. 168 moons orbit the
"full-size" planets (Earth, Mars, Jupiter,
Saturn, Uranus, and Neptune), while 6 moons orbit
the smaller "dwarf planets" (Ceres, Pluto,
Haumea, Makemake, and Eris). Others orbit
asteroids and Trans-Neptunian objects. - Mercury and Venus have no moons
3Which planet? How many?
- Earth 1 moon Luna
- Mars 2 moons
- Jupiter 63 moons
- Saturn 62 moons
- Uranus 27 moons
- Neptune 13 moons
- Pluto 3 moons
- Haumea 2 moons
- Eris 1 moon
- When we consider that Saturn could have as many
as 1 million moons, the question arises, What
constitutes a moon?
4What is a moon?
- A moon is a natural satellite of a celestial
body. It can orbit a planet, an asteroid, etc. - Usually a moon orbits either a planet or a dwarf
planet - The official size of a moon is still being
debated and it does not appear that it will be
settled soon.
5Ten largest moons in the solar system
- Ganymede - Jupiter - 5268 kilometers in diameter
- Titan - Saturn - 5150 kilometers in diameter
- Callisto - Jupiter - 4806 kilometers in diameter
- Io - Jupiter - 3636 kilometers in diameter
- Moon - Earth - 3474 kilometers in diameter
- Europa - Jupiter - 3122 kilometers in diameter
- Triton - Neptune - 2706 kilometers in diameter
- Titania - Uranus - 1578 kilometers in diameter
- Rhea - Saturn - 1528 kilometers in diameter
- Oberon - Uranus - 1523 kilometers in diameter
6Oddball moons
- Triton travels around Neptune backwards and could
be a captured body from the Kuiper Belt. In fact,
Triton may look a lot like Pluto. - Titan, the second largest moon in the solar
system, is an icebox Earth, with a thick
atmosphere, methane meteorology, and youthful
surface. - Ganymedes icy mantle could contain a liquid
ocean layer, but evidence for that is not
conclusive.
7Which is the largest moon in the solar system?
- Luna
- Ganymede
- Titan
- Triton
8The planet with the most moons is
- Saturn
- Jupiter
- Neptune
- Venus
9A moon is.
- Anything that orbits a celestial body thats
bigger than a breadbox - a natural satellite of a celestial body
- Bigger than a truck
- A natural satellite of a celestial body that
orbits a planet in the same direction as the
planets rotation
10The moon that orbits its planet in the direction
opposite the planets rotation is
- Ganymede
- Io
- Triton
- Titan
11(No Transcript)
12How do we know what we know about the moons?
- Mariner 1-10 1962 to 1973
- Pioneer 10 and 11 1972 and 1973
- Voyager 1 2 1977
- Galileo 1989
- Cassini - 1997
- LRO (Lunar Reconnaissance Orbiter) - 2009
- Hubble (1990) and Kepler (2009)
13Luna the Earths moon
14Luna
- The Earths only natural satellite
- Second brightest object in our sky
- Albedo of Luna is .07 (reflects 7 of the light
that hits it), surface is color of charcoal - Fifth largest satellite in the solar system
- 1/4th the diameter of the Earth
- 1/81st of the Earths mass
- Synchronous rotation with the Earth we always
see the same side of the moon
15The two sides of the moon
The side we always see
The dark side of the moon
16Actually we see more than we know
- Due to the lunar libration, or a slow rocking
back and forth motion, we actually see about 59
of Lunas surface on the side that faces us.
17The side hardly anyone sees
- Taken by Clementine spacecraft, this is a mosaic
picture of the south pole of Luna
18What we see changes
- What we see depends on the phase of the moon from
the sliver of a new moon to a full moon when the
moon is behind us, reflecting the Suns light
19What we see also depends on how close Luna is to
the Earth
20What is the cause of the rocking back and forth
motion?
- May be due to extended influence of Earths
gravity on the moon while it is retreating from
the Earth - Moons core is actually off-center
21What are the numbers?
- Moon Numbers Size 3,476.2 kilometers -- 0.2725
Earths -- 14th largest solar system body Orbit
384,400 kilometers from Earth Calendar 1 lunar
day 29.53 Earth days - Our Moon is retreating (moving away) at about 3.8
centimeters (1.5 inches) per year.
22Our moon orbits the Earth
- 24,000 km away.
- 384,000 km away.
- Whenever it feels like it.
- Every couple of months or so.
23Luna is the ________ largest satellite in the
solar system.
- Second
- Third
- Fourth
- Fifth
24Internal structure of our Moon
- Geologically distinct mantle, crust and core
- Solid inner core is probably high in iron content
approximately 240 km in diameter - Liquid iron outer core and an area of partially
melted boundary between core and mantle
25Crust
- The dark, featureless areas are called maria,
thought by early observers to be seas on the
surface - Mare are solidified pools of basaltic lava
- Maria are found almost exclusively on the side
facing the Earth and make up 31 of the surface - Lighter colored regions, terrae, are highlands
- It is not made of cheesesorry
- Neither is there a man in the moon
26Where did it come from?
- Three traditional theories
- Moon and Earth developed at the same time
(condensation hypothesis) - Moon was made of material that came from the
Earth (fission hypothesis) - Moon was captured by the Earths gravity (capture
hypothesis)
27Large-impact hypothesis
- Large celestial body struck the Earth in its
early stages - Most of the iron merged with Earth and
differentiated into the core - Most iron poor debris formed a ring around Earth
that accreted into Luna - Evidence? Composition of lunar rocks, signs of
intense heat,