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131 Cards in this Set

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  • Back
1 AU = ??? km
1.5 * 10^8 km
Skinny Angle Formula
sin a = D / d
a = D / d
d=??? AU
Baseline = 1 AU
a = 1 arcsec
d = 206265 AU = 1 pc
1 ly = ??? AU?
63,240 AU = 1 ly
1 pc = ???? ly?
3.26 ly = 1 pc
The sun travels on the _______.
There is a _-minute difference each day of the Sun's position against the stars.
4 minute delay
Angle between Earth's orbit and Earth's rotational axis is called _______ and has a value of ______.
Obliquity, 23.5 degrees
# of constellations?
The point directly overhead is the __________.
_________ is the line between the poles and the zenith.
A star's longitude is it's ______ _______.
Right ascension
A star's latitude is it's _________.
Right ascension zero-point is _____________.
Vernal equinox
Who cataloged 850 stars by position and magnitude?
The celestial poles slowly changing position is called _________
Precession is due to what?
The gravitational pull of the Moon and the Sun on the Earth.
How long does one cycle of procession take?
26,000 years
The spinning of a body around its axis is called ________.
The orbital motion of one body around another due to gravity is called __________.
T/F The seasons are due to a change in distance from the sun.
False - the seasons are caused by obliquity.
Where is the Sun at the Summer Solstice?
It's highest North position, 23.5 degrees above the celestial equator.
Where is the Sun at the Autumnal Equinox?
12 hours away from the Vernal Equinox, on the celestial equator.
The solar day is how long?
24 hours, 0 min, 0 sec.
The sidereal day is how long?
23 hours, 56 min, 04 sec.
Why is the sidereal day shorter than the solar day?
Because the Earth is revolving while it is rotating, so the day with respect to the background stars is shorter.
How many time zones are there? How many degrees are in each?
24 time zones, 15 degrees each.
How long is the year in the Julian calendar?
365.25 days.
How long is the year in the Gregorian calendar?
365.242 days.
What is our current calendar system?
The Gregorian calender.
What are the current rules for a leap year?
Divisible by 4? Yes, unless
Divisible by 100? No. unless
Divisible by 400? Yes.
Light has both _____ and ______-like characteristics.
Wave and particle.
Emitted light depends on an object's _________.
The motion of a light source affects _________
Maxwells theory states....
Since mag. and electronic fields propagate at c, light must be a form of electromagnetic radiation.
The distance between successive crests of a wave is __________
Number of crests that pass a specific point in one second is________
frequency, f or v
1 nm = ___ m?
1 x 10^-9 m
c = ?? [km/s]
3 x 10^5 km/s
c = what times what?
wavelength times frequency.
lambda times v
What proved that light has wave-like characteristics?
The double-slit interference pattern.
Apparent brightness is called ______.
Flux = ??
Luminosity / 4 pi d^2
Flux1 / Flux2 = ???
d2^2 / d1^2.
Jean Foucalt used what to measure the speed of light?
A rapidly rotating mirror.
What is the range of wavelength of visible light?
400 nm (blue) --> 700 nm (red).
What is the list of wavelength ranges, in increasing wavelength?
Gamma, X-Ray, UV, visible, IR, microwave, Radio
The coldest temperature is ____
0 K.
An object that absorbs all the light that impinges on it is called a _______.
T/F A blackbody emits energy at specific wavelengths only.
False - a blackbody emits some energy at ALL wavelengths.
T/F A blackbody emits more energy at all wavelengths than does a cooler one.
The higher the temperature, the (shorter/longer) the wavelength at which maximum energy is emitted.
What is Wien's Law?
wavelength(max) = 0.0029/T
meters, K
What does Wien's law describe?
The wavelength of maximum energy emission compared to the temperature - w.l.max = .0029 / T
What is the Stefan-Boltzmann law?
E = 4 pi R^2 sigma T^4
E(star1)/E(star2) = ?
(T1 / T2)^4
assuming equal sizes. else
How many dark lines are seen in the solar spectrum?
600 dark lines.
What are the 3 types of spectra?
Continuous, Absorption, Emission
What are Kirchoff's Laws?
Hot opaque body - continuous
cool gas in front of continuous - absorption
hot gas - emission
What is the photoelectric effect?
Light kicks off electrons from surfaces.
What does the energy of a photon equal?

E = ??
E = hv
E = hv = h c/ lamda
What are the units of Energy in

E = hv = h c /lambda
Joules [J]
How many J in an eV?
1.6 x 10^-19 J / eV
What was Rutherford's experiment?
Discovered the nucleus by observing some alpha-particle (He nuclei) bouncing back from gold foil instead of passing through.
Aborption of a photon produces what kind of spectrum?
An absorption-line spectrum.
What is the Rydberg formula?
1/lambda = R(1/m^2 - 1/n^2)
m=1 lyman
m=2 balmer (hydrogen)
m=3 paschen
m=4 brackett
The Lyman series is what kind of radiation?
Ultraviolet (UV)
Lyman - UV
The Balmer series is what type of radiation?

Balmer = Hydrogen = visible
The Paschen series is what type of radiation?
What is the Doppler shift equation?
delta*lambda / lambda =
v / c

v = c delta*lambda/lambda
What are the 3 benefits of telescopes?
Magnification, Brightness, Resolution
What are the two main techniques used to manipulate light?
Refraction and Reflection
The focal length is the distance from the _____ to the _______.
lens to the focus = focal length
Magnification = ????
Focal length of objective / focal length of eyepiece

M = F / f
A reflecting telescope with a mirror reflecting to a focus removed from the tube is _____________
Newtonian focus
The un-manipulated focus of a reflecting mirror is the __________
prime focus
A reflecting telescope with a mirror pointing back through the primary mirror is ______________
Cassegrain focus
The light gathering ability of a telescope is proportional to what characteristic?
The Radius^2 squared
The radius of "what" affects the light gathering ability
The objective lens or the primary mirror
What is the equation for the resolution of a telescope?
alpha = 2.1x10^5 lambda / D

alpha in arcseconds
D is the diameter of the telescope
When different wavelengths are brought to different focal points, it's called ______________
Chromatic aberration.
How can you minimize chromatic aberration?
Add different materials and shapes together.
Chromatic aberration affects what kinds of telescopes?
Refracting telescopes
What is the problem called with different reflections being brought to different focal lengths?
Spherical aberration
How can you minimize spherical aberration?
Parabolic mirrors
How much bigger is the Sun than the Earth?
100 X bigger
How many times as massive is the Sun than the Earth?
A million times as massive
What is the surface temp of the sun in degrees F?
10,500 degrees F
How long does the sun take to rotate?
1 month
What are the 3 layers of the solar atmosphere, bottom to top?
Photosphere, Chromosphere, Corona
T/F the photosphere is a physical boundary on the sun.
False- it is an optical boundary
What produces the sharp edge of the sun?
The absortion of light (photons) by H- molecules
What is the height of the photosphere (in km)?
the photosphere is 400 km high
What the surface temp of the photosphere in K?
5,800 K

minimum = 4500 K
The surface of the photosphere is covered with _________
Why is the edge of the sun dimmer?
Limb Darkening, dimmer light comes from the cooler, higher deepest region visible on the edges
How big is a granule?
Size of Texas + Oklahoma
What's the temp like on a granule?
Centers are 50-100 K hotter than the edges
How long does a granule last?
8 minutes
What causes the motion of hot gas rising and cooler gas sinking around the edges of granules?
Where was Helium first discovered?
In the chromosphere of the Sun during a solar eclipse
What is the height of the chromosphere (in km)?
2000 - 3000 km
What is the temp of the chromosphere?
4500 K - 10,000 K
What are the surface features of the chromosphere?
How tall are spicules?
As much as 10,000 km high
How hot is a spicule?
The temp quickly rises to 1,000,000 K
How long do spicules last?
About 15 min.
How many spicules exist at a given time?
About 300,000
What is the height of the corona?
Millions of kilometers
What is the temperature of the corona?
Millions of K
What heats the corona?
Magnetic Fields
How is the corona best viewed?
In the X-ray during a solar eclipse
The solar wind's interaction with the Earth's atmosphere creates ________
Why aren't there eclipses all the time?
Because the moon's orbit is angled to the ecliptic by 5 degrees
What are the three types of phenomena on the active sun?
Sun spots, Prominences, Flares, Coronal holes
What is the phenomenon in the photosphere?
What is the phenomenon in the chromosphere?
What is the temperature of a sunspot relative to the surface?
1500 K cooler than the surface
How long does a sun spot last?
About 2 months
Do sunspots like grouping or being isolated?
Groups of 2-20
Are sunspots usually bigger than Earth?
What type of rotation does the sun have?
Differential rotation
What is the day of the sun at these latitudes: equator, 40 degrees, 80 degrees
equator - 25 days
40 deg - 28 days
80 deg - 36 days
How long is the average solar cycle?
11 years
During the course of a sun spot cycle, regions of sunspot occurrence move:
equatorward, moving from 30 degrees to 10 degrees
The curving loops of promininces are anchored by what?
Differing magnetic poles
Prominences are associated with.....
Sun spots
How long do prominences last?
A few hours to a few months
Coronal holes are best seen how?
in X-rays
How much energy is in a solar flare?
Millions of H bombs
What was the Maunder minimum?
From 1645 to 1715 there were NO SUNSPOTS!