Currently, there are 246 candidates outside of our solar system that could be Earthsized planets.
What is life?
There is no clear cut definition.
Follow the water every form of life is dependent on water during some point in
Possibility of life:
Methods of Finding Planets Orbiting Stars continued
Method 1: The Doppler Method
A star is orbited by an exoplanet. When the star is moving away from us, the stars
spectral lines will appear:
Red-shifted; Note: we cant see the planet, so there is no spect
The Solar Thermostat
The solar thermostat stabilizes energy production in the core.
Slight drop in core temperature; leads to a large decrease of fusion rate; lowers the
core pressure; causes the core to contract and heat up; restores fusion rate to norma
The Sun is the biggest planet in the solar system.
Answer: False the sun is a star, not a planet.
The Sun is approximately 1,047 Jupiters by mass.
The size of the Earth and the size of the sun spots are approximately the same.
What is the most abu
The Solar Cycle
Solar minimum to solar maximum back to solar minimum over a course of 11 years.
Sunspot activity is rare during solar minimum, active during solar maximum.
The Sun can rotate at a different rate at the equator than at the poles because it
Moons and Rings of the Jovian Planets
Why do Uranus and Neptune look blue?
Their clouds are white, but methane in their atmospheres absorbs red light, so the
planets look blue.
Methane in hydrogen atmosphere acts as a blue filter, like looking through blu
Small Objects in the Solar System: Rings, Asteroids, Meteorites, the Kuiper Belt
Ring systems typically have many gaps.
Some of these gaps are made by shepherd moons. Why?
Keplers 3rd law implies closer-in orbits go faster; moon passes outer ring particle
More on Atmospheres
Why is Venus so different from Earth?
If Earth moved to Venus orbit, more intense sunlight would raise surface
temperature by about 30oC.
Then higher temperature increases evaporation, and warmer air holds more water
Impact and Craters (continued)
How do craters form?
Things orbit the Sun and collide with each other at speeds of 10-30 kilometers per
second, fast enough to vaporize some rock and make an explosion, so craters tend to
Larger impacts can produce
Interiors and Atmospheres of the Terrestrial Planets
Larger planets cool more slowly than smaller ones, but they are heated just as
quickly (or quicker).
Larger planets are hotter, more molten, more convective, and more geologically
active than their smal
Stars Balls of plasma which produces energy by nuclear fusion.
Planets Rocky, icy, gassy; dont produce much energy.
Moon Any large body which orbits a planet.
Nebula A cloud of gas (bright) and dust (dark).
Definition of planet:
- Planets orbit stars dire
Planet Formation (continued)
Dust keeps us from seeing stars and planets clearly.
Rock line Rocks will also vaporize if its too close to the sun (not just frost line).
Terrestrial Planet Formation (inside the frost line):
- Dust grains settle in the disk
The Formation of the Solar System
What properties of the solar system must our model for its formation explain?
- All planets orbit in the same direction (prograde; retrograde for reverse)
- Most planets orbit in the ecliptic plane
What is the overall sha
As something is made hotter, the peak of the wavelength shifts towards blue (higher
frequencies & energies, shorter wavelengths).
Blue stars are hotter than red stars, white stars, and pink stars with polka dots.
A hot surface releases a broad ran
The Nature of Light
How do we perceive light?
Passes through cornea (light is bent), goes through lens (light bent again), then we
focus in on the colour. We can only perceive a combination of red, green, blue. Rods
and cones (RGB) in eyes.
What is white
A solar system consists of a star orbited by planets, moons, and lots of debris
(comets, asteroids, dust)
Inner & Outer Solar System
Terrestrial = Earth-like
Terrestrial planets small, rocky, thin or no atmosphere, few moons
Few probes sent to Mercury; no
Tide and the Length of Day
- Pulls objects at same rate regardless of mass (Newtons second law)
- Gets weaker as you move farther away from the centre of the Earth (or moon,
- Pulls towards the centre of the Earth (or moon, sun, etc.)
The Moon and its Phases
First quarter -> waxing gibbous -> Full -> waning gibbous -> last quarter -> waning
crescent -> new moon -> waxing crescent
If from the moon sees Earth as waxing gibbous, the moons phase from Earth is
Constellations and the Night Sky
Constellations Stars in groupings (imaginary outlines)
Circle = 360 degrees -> 1 degree = 60 arc minutes -> 1 arc minute = 60 arc seconds
(measures of angle)
From Pluto, we wouldnt see the same constellations as well, beca
Gravity Only force of nature without an anti counterpart (eg. Electromagnetic
force have + and - charges). Zero electromagnetic force, lots of gravity.
Newtons Law of Gravity The force of gravity between masses M and m is equal to
the product of their mas