Grab Bag
What is the geocentric model?
The proposed structure of the solar system where the sun and all of the planets revolve around the earth.
What is the name of the group of 12 constellations that the sun passes through throughout the year?
The ecliptic
What part of the electromagnetic spectrum can we see?
Visible Light
How many laws of planetary motion did Kepler have?
3
Reflecting
Define a lightyear?
A unit of distance equal to the distance that light travels in one year's time
How many arcseconds are there in a degree?
3600
What part of the electromagnetic spectrum has the highest energy?
Gamma Rays
Who originally proposed the Heliocentric model of the solar system?
Nicolaus Copernicus
-Better resolution
-Able to take in more light
What is the word for the slow rotation of the Earth's axis (Not the Earth's rotation AROUND its axis)?
Procession
What is a sidereal day?
How long it takes for Earth to rotate on its axis measured by a non-solar star returning to its position in the sky.
What is an emission spectrum?
A spectrum of light measured from a hot object that can show us the composition based on the wavelengths emitted.
What concept did Ptolemy use to explain the apparent backwards motion of planets in the night sky?
Epicycles
The focal length of a telescope helps determine its...
Magnification
What shapes are the two lenses in a Keplerian telescope?
Both are convex
Explain why summer in the northern hemisphere is winter in the southern hemisphere, and vice versa.
Because the Earth is tilted, when it is tilting towards the sun the northern hemisphere is receiving more direct sunlight than the south. When it is tilted away from the sun, the southern hemisphere is receiving more direct sunlight than the north.
Due to the Doppler Effect, what wavelength do things moving away from the observer shift to?
Redder/Bigger
-Venus goes through phases, implying it too orbits the sun.
What is one way to minimize atmospheric blurring of telescopes
-Controlling optics based on temperature and orientation
-Put telescopes in space
-Put terrestrial telescopes as high altitude as possible
Define a parsec.
A unit of distance equal to a point that has a parallax of one arcsecond.
Why don't solar eclipses occur every month?
Earth and the moon's orbit do not exist on the same plane, meaning they only line up every ~6 months.
The blackbody spectrum relates what two variables?
Temperature and emission spectrum
Give the definition of Kepler's Second Law (NOT the implications)
A planet orbiting the sun will sweep out equal areas in equal amount of time, no matter where it is in its orbit.
Why is the image of a Galilean Telescope NOT inverted?
There is a concave lens placed BEFORE the focus, preventing the light rays from crossing each other and inverting the image.