A Look at Our Solar System: The Sun, the planets and more by Firdevs Duru
Week 1 An overview of our place in the universe An overview of our solar system History of the astronomy Physics of motion of the planets
Week 2 Our star Sun (physical properties, layers, fusion) Our home Earth (motion, interior, atmosphere, auroras) Our companion Moon (physical properties, eclipses, tidal effects)
Week 3 Terrestrial planets (Mercury, Venus, Mars) Physical properties, missions
Week 4 Jovian planets (Jupiter, Saturn, Uranus, Neptune) Trans-Neptunian Objects
General Relativity: Mass tells the spacetime how to curve Spacetime tells the mass how to move
Jupiter
Some Properties It does not have a solid surface Colors are due to liquid and solid droplets Alternating dark belts and light zones Bright and dark spots Color changes from reddish-pink to blue-gray (Sulfur and phosphorus)
Diameter Size and Differential Rotation Jupiter s polar diameter is about 6% less than its equatorial diameter because of its fast rotation and large size. Equatorial regions rotate once every 9h50m It takes about 6 minute longer at higher latitudes.
Atmosphere 99% Hydrogen molecules (H 2 ) and Helium atoms (He) H 2 :He 4:1 Other gasses: methane (CH 4 ), ammonia (NH 3 ), water vapor (H 2 O)
Clouds Arranged in several layers: water ice clouds, ammonium hydrosulfide clouds, ammonia ice clouds. The color comes from molecules such as phosphine
Great Red Spot q In the southern hemisphere q A region of swirling, circulating winds q Rotates counterclockwise q It rotates at a similar rate as the interior of the planet q High pressure region
White Ovals Circulating storm systems Look white because of their high cloud tops Low pressure regions
Dark brown ovals q Last only for a few years q They are long-lived holes in the overlying clouds q Low pressure regions
Interior
Internal Heat Jupiter emits about twice as much energy as reaches the planet in the form of sunlight It is bright and self-luminuous 40% of the energy comes from its internal sources Heat left from the planets formation
Magnetosphere
Ring Discovered in 1979 during Voyager 1 flyby Lies in the plane of the equator, about 50000 km above the cloud layer Composed of dark fragments of rock and dust chipped of the inner moons by meteorites
Galilean Satellites
Io Most geologically active object in the solar system. Cratered surface. Does not have huge volcanic mountains (due to the lava being too fluid)
Io Loki: emits more energy than all of Earth s volcanos. The yellow, orange and black-brown colors are due to sulfur compounds. Has a iron-rich core, a thin atmosphere consisting mainly of sulfur dioxide.
Europa Few craters on the surface à effect of ancient meteoric impacts are erased. No high hills. Vast network of lines crossing the fields of water ice. Covered by an liquid water ocean with a frozen surface layer.
Systems of ridges and grooves, which may be due to the movement of icy crust (due to tidal distortions).
Flat chunks of ice that have been broken apart and reassembled. Ice layer: Several kms thick. Ocean: 100 km deep.
Ganymede Largest moon in the solar system. Many impact craters, light and dark regions on the surface. Surface darkened due to micrometeorite dust. Has a system of grooves and ridges due to crustal tectonic motion.
Similar in size and composition to Ganymede. Callisto More heavily cratered. A series of concentric ridges surrounding two large basins. Crust is ice and shows no signs of geological activity. Varying magnetic field induced by Jupiter s magnetic field, suggesting an ocean with salty water under the surface.
Saturn
WAVE at SATURN Day
Saturn Seen fainter due to its distance Has banded atmosphere similar to Jupiter Spectacular ring system
Some properties Polar diameter is less than its equatorial diameter (90% of the equatorial) Belts and zones Spots are present Has differential rotation as well Rotation rate is 26 minutes smaller at the poles Interior rotates at the same rate as the poles.
Atmosphere Similar to Jupiter H:He = 7:1 Traces of methane and ammonia It is about 150 K cooler than the Earth s atmosphere at a given pressure
Troposphere contains clouds in three distinct layers: Ammonia ice Ammonium hydrosulfide ice Water ice Total thickness is about 250 km Thicker, harder to see the colorful clouds Has bands, oval storm systems, turbulent flow patterns The winds are much faster than in Jupiter Clouds and Weather
Interior
Internal Heating Saturn is smaller à Not the excess heating Helium does not dissolve in liquid hydrogen since the internal temperature is lower, but forms droplets Sinks towards the center Planets gravitational field compresses it and heats up
Rings
A is farthest from the planet and separated by the Cassini division B is brightest, C is almost translucent Many gaps and large numbers of ringlets Some short-lived features in the B rings, called spokes
James Clerk Maxwell: rings must be composed of small number of solid small particles, all independently orbiting Saturn Idea supported by Kepler s observations and Doppler shift measurements Rings are highly reflective à made of ice Water ice is the main constituent Small rocky particles and dust mixed with ice are also present
Roche Limit Roche Limit: The critical distance at which the tidal forces become bigger than the internal forces holding the moon.
Moons of Saturn Saturn has 60 known satellites, eight of them with diameters larger than 300 km. All of them are heavily cratered. Their densities suggest they should contain at least 50 % ice.
Titan Largest moon of Saturn. Similar to Ganymede and Callisto in size and composition. Can be seen from the Earth. Has a rocky core with a thick mantle of water ice and a thick layer of liquid water a few tens of kms below the surface.
Titan s Atmosphere It has a thick atmosphere (thanks to its low temperatures). Made of N 2, methane and other hydrocarbons. It is cold and dense. The temperature is 94 K. Also contains a haze of aerosol droplets and particles.