Astronomy Exam 1 Flashcards
What is Latitude?
North to South
What is Longitude?
East to West
great circle running though Greenwich,England and the North and South Pole
Prime Meridian
What is the latitude of ASU?
33 N
At what angle will the North Star be tonight in Tempe?
30 degrees
At what angle will the North Star be tonight at the North Pole?
90 degrees
stars’ locations in the sky given by latitude
declination
right ascension is?
the stars’ location in the sky given by longitude
What way do stars appear to rotate around the North Star?
counterclockwise
The Sun rises in the East and sets in the West. Which way is the Earth rotating?
toward the east
What is teh celestial sphere centered on?
the earth
This is when the days have equal amounts of daylight and nigthtime
Equinoxes
What is a Solstice?
the days that have the most unequal amount of daylight and nightitme
what is insolation?
the amount of solar energy incident on a suraface area
what does insolation depend on?
the angle of the sun
What is the sunlight angle of incidence for a equinox?
90 degress
what is the sunlight angle of incidence for a solstice?
23.5 degrees
our earth’s orbit is
eccentric
what is teh Perihelion?
the closest point to the Sun that occurs during Northern Winter
What is the farthest point to the Sun that occurs during Northern Summer called?
Aphelion
What does precession do ?
the earth spins like a top
what does Obliquity do?
the axis tilt changes about +/- 1 degrees, period is about 40,000 years
this is what causes the orbit shape to change over time. the period is about 100,000 years.
Eccentricity
why does we only ever see just one face of the moon?
because of the synchronous rotation, rotation period=orbit period
what does angular size depend on ?
distance
how is light created?
light is generated when electric charges are forced to oscillate back and forth
what is visible light an example of?
electromagnetic radiation
what happens when charged particles change their motion?
they emit electromagnetic radiation
The distance between the same point on two successive waves
wavelength
the time between passages of wave crests
Period
what is frequency?
the number of waves that pass each second
how do you find period?
P=1/f
how do you find the frequency of the wave?
f = c / lamba
what is the speed of light?
300,000km/sec
how much a Parsec in light years?
3.26 lightyears
how many AU is in 1 Parsec?
206265 Au
what is the relation between wave frequency and wavelength ?
c = f x lamba
how do you calculate teh energy of a photon?
E = h x f
what do refractor telescopes use?
lenses
what do reflector telescopes use?
mirrors
what is the equation for the area of a circle?
pie*r^2
what will happen to the light of two nearby stars?
when the light of two nearby stars separated y only a very small angle will be smeared together (Diffraction Limit)
what is the highest angular resolution possible with ?
telescope arrays
a faint star has a
large magnitude
a small magnitude means a
bright star
what is apparent magnitude?
magnitude based on brightness, depends on distance
what is absolute magnitude?
magnitude based on luminosity, distance of 10pc
how can we find the composition of a star?
from the spectra, absorption lines
how to find the temperature of a star?
wien’s law - relationship between peak wavelength and temperature
the total amount of energy emitted at all wavelength is ?
flux
how do we find the radius of a star
luminosity plus temperature
the fraction of light that is reflected from a planet?
albedo
how is planet temperature determined?
by the balance of sunlight absorbed and energy radiated from the planet into space
two reasons how Earth’s atmosphere interferes with telescope observations
- the atmosphere absorbs some waves of light so they never make it to the telescope
- the earth’s atmosphere isnt uniform, so when light hits it it becomes bended and distorted.
where are neutrino detecors located?
deep underground or under water/ice
why are neurtinos so hard to detect?
because they nonreactive with matter
what defines momentum ?
mass x velocity
