Download A Look at Our Solar System: The Sun, the planets and more

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 (H2) and Helium atoms
(He)
H2:He 4:1
Other gasses: methane (CH4), ammonia (NH3), water
vapor (H2O)
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.
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.
Callisto
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
Clouds and Weather
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
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 N2, methane and other hydrocarbons. It is cold and
dense. The temperature is 94 K. Also contains a haze of
aerosol droplets and particles.