Solar System Physics Flashcards
What does the solar system consist of?
the Sun orbited by the 8 planets (4 terrestrial, 4 jovian), minor bodies
including dwarf planets (e.g. Pluto), asteroids, comets, and other debris left over from the formation of
the solar system.
planet
in orbit around a star, and is massive enough to be spherical
(or nearly spherical!) and to have cleared its own orbit of other objects.
2 groups of planets in the solar system
terrestrial and jovian
each has very distinct properties
what is gravity responsible for?
orbits of planets around the Sun, and moons/satellites around planets.
Gravitational potential energy released by matter falling towards a gravitating object…
is converted to kinetic energy, which can in turn be converted to other forms (e.g. heat).
surface gravity
Surface gravity is the gravitational acceleration (force per unit mass) at a planetary surface.
tidal force
The tidal force is the difference in gravitational force experienced by 2 parts of an object.
If a planetary atmosphere is hotter than the escape temperature for a given atom or molecule…
then that atom or molecule is not present in the atmosphere.
When is the escape temperature higher?
for more massive planets (stronger gravitational acceleration)
and for heavier atoms/molecules (need more energy to go fast enough to escape).
Scale height
Atmospheric pressure decreases exponentially with increasing height. The rate at which it
decreases is given by the scale height.
If the atmospheric temperature increases…
the scale height increases, and the atmosphere extends further out from the planet or star.
Jovian planets are primarily composed of…
Hydrogen and Helium
outer layers of jovian planets
Are gaseous, therefore rotate differentially (not all latitudes have the same angular speed) and are slightly oblate due to the centrifugal force being stronger at their equators.
outer layers of Jupiter and Saturn
The gaseous outer layers of Jupiter and Saturn display complex flows (zones and belts, storms,
vortex structure).
Jovian planets core
Jovian planets have cores composed of dense ‘soups’ of rock and ices, or rock alone
strong magnetic field in Jupiter and Saturn
Liquid metallic hydrogen in Jupiter’s and Saturn’s interiors produces a strong magnetic field.
Weak magnetic fields in Uranus and Neptune
Ionic ‘oceans’ in Uranus and Neptune produce weaker magnetic fields.
how are the interiors of jovian planets heated
heated by the gravitational potential energy released as heavier elements sink slowly towards the core.
Why are rings thin?
Rings are thin because inelastic collisions in the vertical direction remove energy and linear
momentum from the colliding particles, while angular momentum is conserved.
Roche stability limit
Within a critical radius, known as the Roche stability limit, an object will be pulled apart by tidal
forces. Saturn’s rings lie mostly inside this radius.
What do tidal forces acting on moons cause?
frictional heating of the moons
what can tidal friction on a planet do?
slow down its rotation
Because angular momentum of planet and moon must be conserved,
this means the planet speeds up, so its orbital radius increases.
The inner 2 Galilean moons
rocky
show more evidence of volcanic or tectonic activity, and less evidence
of impact cratering