final Flashcards
how many stars in our galaxy
100 billion
universe hierarchy
solar system
milky way
local group
(virgo) local supercluster
how many galaxies in observable universe
100 billion
distance to sun
8 light min
distance to closest star (and name)
alpha centuri
3 years
closest galaxy and name
andromeda
2.5 million years
radius of observable universe
14 billion years
when in the year is does milky way form
feb
when in year does earth form
sept 3
when does life begin on earth
sept 22
what is science
questions, evidence, experiments, trial and error
what was the ancient model of the universe
- geocentric
- heavens are perfect
- everything orbits the earth
ptolemys model of universe
same as greeks but with epicycles due to retrograde of mars
copernican model
sun centred model
keplers 3 laws
1) planets orbit sun in elliptical path with sun at focus
2) planet sweeps out equal area of ellipse in equal time
3) P^2 = a^3
what did gelileo do
prove keplers ideas and thus proved heliocentric model
how do we get info from universe
- light
- neutrinos
- gravitational waves
3 types of astronomical data
- imaging
- spectroscopy
- time series
what is imaging
- detect pos and brightness of light
- can tell us about shape, color, and brightness
spectroscopy
- intensity of light at different wavelengths or colors
- tells about temp, composition, density
time series
- change of intensity of light, or change in position
what is a atom made of
-elec, prot, neutrons
- most mass is in nucleus
absorbtion of light
- atom jumps up level as it gained energy
- look at cloud of gas directly in front of source
emission of light
spontanius
- electron fall a level as it lost energy
- look at cloud of gas from the side
chemical fingerprint
we can look at star and see the absorbtion/emission lines to see the composition of the surface.
it also lets us mesure the speed of the object with doppler shift
refracting telescope
- has a lens that collects light
- light is focused to the focal point
- light then goes to eyepiece
reflecting telescope
- a concave mirror that focuses light to a mirror that directs it to the eye peice
2 most important properties of telescope
- light collecting power
- angular resolution
what is light collecting power
- depends on area of mirror/lens
- makes image more clear
what is angular resolution
- depends on diameter of mirror/lens and wl of observation
- is the smallest detail you can resolve
what is interometry / apreature synthesis
linking telescopes to mimic a large angular resolution (largest speration between dishes)
why put telescopes in space
to prevent atmospheric blurring, only needed for xray, uv, gamma, ir
what is adaptive optics
deform mirror to compensate for distortion of the atmosphere, by using laser and reference star
