Transcript The Sun and Solar System

The Sun, Solar System and
Galaxies
Dr. Alan F. Weekes
The Sun
A large sphere of gas that gives off light, heat
and other electromagnetic energy generated
by nuclear fusion in its core. It is a star.
The whole solar system is held by the sun’s
gravity.
The greater the mass of an object the greater its
gravitational effect.
The gravitational effect lessens with distance.
Objects are held in elliptical orbits.
The Core- where fusion
takes place
Photosphere- the layer
of the sun we see
Sunspots- cooler,
storms on the surface
Solar flares- blasts of
energy, from sunspots
Prominence- loops of
gas following magnetic
fields
Corona- Outer
atmosphere of the sun
Effects of the Sun on Earth
Light & heat
Tides
Auroras- from flares, energy excites
areas in the magnetic field, radio may
be disrupted, power outages
The Sun- Websites
Spaceweather
Nasa
Sun Song
The Inner Solar System- Mercury
Closest planet to the Sun
Moonlike surface, cratered
No atmosphere
Cold night side,
hot day side
No Moon
The Inner Solar System- Venus
Twin to Earth, size and density
Surface like a dry Earth
Volcanoes, “continents”, “ocean basins”
Craters, rifts
Heavy CO2 Atmosphere, 90x weight of Earth’s
Greenhouse Effect, surface temperature ~470 C
or 870 F
Sulfuric acid clouds
No Moon
The Inner Solar System- Venus
Venus
without
clouds
(Radar
Image)
Video Clip: Venus
The Inner Solar System- Earth
The only planet we know
of that supports life.
Pleasant atmosphere of N,
O, Ar, CO2
One moon
71% covered with water
Only planet to have water
in 3 physical states
Video Clip: Earth
The Inner Solar System- Mars
~1/2 of Earth’s diameter
~1/3 of Earth’s gravity
Thin CO2 atmosphere
Wind and dust storms
Seasons like Earth, similar tilt
Days like Earth, similar rotation
Evidence of past water flows,
glaciers
Large volcanoes, large valleys
Two moons, small former
asteroids
The Inner Solar System- Mars
The Inner Solar System- Websites
http://mars.jpl.nasa.gov/3D/stereospacecraft.html
http://mars.jpl.nasa.gov/MPF/mpf/anagl
yph-arc.html
http://www.jpl.nasa.gov/multimedia/sli
deshows/mars-200701/index.cfm
http://www.jpl.nasa.gov/videos/mer/me
r20070104/
The Outer Solar System- Jupiter
The largest planet.
Gas Giant, hydrogen and helium
Great Red Spot, large persistent (>300 years)
high pressure storm
4 large Galilean Moons
Ganymede, Callisto, Io, Europa
Io, most volcanically active place in solar system
59 smaller moons (total 63)
Explored with the Galileo Spacecraft
Jupiter Images Galileo Spacecraft Pages
The Outer Solar System- Jupiter
Ganymedelargest moon, ice
and rock
Europamostly water
ice
Io – no
craters, many
volcanoes
Video Clip Jupiter
The Outer Solar System- Saturn
The ringed planetnote all the gas
giants have some
rings
Low density- less
than water
34 named moons
Titan: only moon
with an atmosphere
Welcome to the Planets (NASA)
Video Clip- Saturn
The Outer Solar System- Uranus
Twin to Neptune in
size and density
Axis is almost at 90o,
seasons would be
long/odd.
Uranus Images
Video Clip- Uranus
The Outer Solar System- Neptune
Uranus’ Twin
21 Named moons
Neptune Images
Video Clip- Neptune
The Dwarf Planets- Pluto
Discovered in 1930 by Clyde W. Tombaugh
Very small, 2274 km (Earth’s Moon 3476 km)
Large moon Charon (1212 km)
Pluto is a double planet system
Pluto and Charon always keep the same side toward each
other
Recently 2 more small moons were found
Nix and Hydra
New Horizons Spacecraft Timeline and Site
http://www.nasa.gov/mission_pages/newhorizons/m
ain/index.html
The Dwarf Planets- Ceres
Smallest dwarf planet now
950 km
Discovered in 1801
First asteroid found between
Mars and Jupiter
Perhaps as much water as all
the fresh water on Earth
The Dwarf Planets- Eris
Discovered 2005
Larger than Pluto at 2400 km
Has one moon, Dysnomia
150 km
The Dwarf Planets- Makemake
It was discovered on March 31, 2005
The name of Makemake, the creator of
humanity and god of fertility in the
mythos of the Rapanui, the native
people of Easter Island, was chosen in
part to preserve the object's connection
with Easter
Diameter from 1,360 to 1480 km
The Dwarf Planets- Family Portrait
Video- Dwarf Planets
Small Solar System Bodies- Asteroids
Mostly found between Mars and Jupiter
Asteroid belt prevented from being a
planet by Jupiter’s gravity
Small Solar System Bodies- Asteroids
Small Solar System Bodies- Comets
Bodies of mostly ice and rock
“dirty snowballs”
Usually very elongated elliptical orbits
Form a tail as they approach the sun
The tail always points away from the sun
Small Solar System Bodies- Comets
Comet Hale-Bopp in 1997 (left)
Comet McNaught as seen from
Swift's Creek, Victoria, Australia
on 23 January 2007
Video Clip- Comet
Galaxies
Galaxies are very large groups of stars
held together by gravity
We are in the Milky Way Galaxy
Named for the band of stars that stretches
across the sky.
Galaxies
Types of Galaxies
Spiral-The largest, usually with spiraling arms.
The Milky Way is a spiral type.
• >200 billion stars
• 100,000 light years across
– Light year- the distance that light would travel in one year
– 300,000 km/sec or 186,000 miles per second
– About 9 trillion km or 6 trillion miles
• We are about 28,000 light years from the center
• The galaxy rotates, we revolve around the center about
once every 220 million years.
• We see the band of stars when we look into the disk of
the galaxy
Spiral Galaxies
Elliptical Galaxies
Irregular Galaxies
A Matter of Scale
From Clusters of Galaxies to the inside of an
Atom
Scale of Size
http://www.htwins.net/scale2/
Powers of 10
How big is big and how small is small?
• http://micro.magnet.fsu.edu/primer/java/scienc
eopticsu/powersof10/
• http://powersof10.com/index.php?mod=power
_detail&id_power=25