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 CO or 870 F No Moon 2 Atmosphere, 90x weight of Earth’s Greenhouse Effect, surface temperature ~470 C Sulfuric acid clouds
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, CO 2 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 CO glaciers 2 atmosphere Wind and dust storms Seasons like Earth, similar tilt Days like Earth, similar rotation Evidence of past water flows, 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/stereo spacecraft.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
Ganymede largest moon, ice and rock Europa mostly water ice Io – no craters, many volcanoes
Video Clip Jupiter
The Outer Solar System- Saturn
The ringed planet note 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 90 o , 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 mythos of the Rapanui , the creator of humanity and god of fertility in the , the native people of Easter Island with Easter , was chosen in part to preserve the object's connection 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