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131 Cards in this Set
- Front
- Back
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1 AU = ??? km
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1.5 * 10^8 km
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Skinny Angle Formula
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sin a = D / d
a = D / d |
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Parsec:
Baseline? a? d=??? AU |
Baseline = 1 AU
a = 1 arcsec d = 206265 AU = 1 pc |
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1 ly = ??? AU?
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63,240 AU = 1 ly
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1 pc = ???? ly?
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3.26 ly = 1 pc
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The sun travels on the _______.
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ecliptic
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There is a _-minute difference each day of the Sun's position against the stars.
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4 minute delay
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Angle between Earth's orbit and Earth's rotational axis is called _______ and has a value of ______.
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Obliquity, 23.5 degrees
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# of constellations?
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88
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The point directly overhead is the __________.
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Zenith
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_________ is the line between the poles and the zenith.
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Meridian
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A star's longitude is it's ______ _______.
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Right ascension
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A star's latitude is it's _________.
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Declination
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Right ascension zero-point is _____________.
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Vernal equinox
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Who cataloged 850 stars by position and magnitude?
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Hipparchus
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The celestial poles slowly changing position is called _________
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Precession
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Precession is due to what?
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The gravitational pull of the Moon and the Sun on the Earth.
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How long does one cycle of procession take?
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26,000 years
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The spinning of a body around its axis is called ________.
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Rotation
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The orbital motion of one body around another due to gravity is called __________.
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Revolution
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T/F The seasons are due to a change in distance from the sun.
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False - the seasons are caused by obliquity.
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Where is the Sun at the Summer Solstice?
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It's highest North position, 23.5 degrees above the celestial equator.
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Where is the Sun at the Autumnal Equinox?
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12 hours away from the Vernal Equinox, on the celestial equator.
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The solar day is how long?
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24 hours, 0 min, 0 sec.
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The sidereal day is how long?
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23 hours, 56 min, 04 sec.
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Why is the sidereal day shorter than the solar day?
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Because the Earth is revolving while it is rotating, so the day with respect to the background stars is shorter.
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How many time zones are there? How many degrees are in each?
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24 time zones, 15 degrees each.
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How long is the year in the Julian calendar?
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365.25 days.
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How long is the year in the Gregorian calendar?
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365.242 days.
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What is our current calendar system?
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The Gregorian calender.
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What are the current rules for a leap year?
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Divisible by 4? Yes, unless
Divisible by 100? No. unless Divisible by 400? Yes. |
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Light has both _____ and ______-like characteristics.
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Wave and particle.
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Emitted light depends on an object's _________.
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Temperature.
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The motion of a light source affects _________
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wavelengths.
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Maxwells theory states....
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Since mag. and electronic fields propagate at c, light must be a form of electromagnetic radiation.
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The distance between successive crests of a wave is __________
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wavelength
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Number of crests that pass a specific point in one second is________
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frequency, f or v
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1 nm = ___ m?
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1 x 10^-9 m
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c = ?? [km/s]
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3 x 10^5 km/s
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c = what times what?
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wavelength times frequency.
lambda times v |
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What proved that light has wave-like characteristics?
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The double-slit interference pattern.
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Apparent brightness is called ______.
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Flux.
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Flux = ??
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Luminosity / 4 pi d^2
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Flux1 / Flux2 = ???
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d2^2 / d1^2.
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Jean Foucalt used what to measure the speed of light?
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A rapidly rotating mirror.
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What is the range of wavelength of visible light?
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400 nm (blue) --> 700 nm (red).
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What is the list of wavelength ranges, in increasing wavelength?
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Gamma, X-Ray, UV, visible, IR, microwave, Radio
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The coldest temperature is ____
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0 K.
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An object that absorbs all the light that impinges on it is called a _______.
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Blackbody.
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T/F A blackbody emits energy at specific wavelengths only.
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False - a blackbody emits some energy at ALL wavelengths.
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T/F A blackbody emits more energy at all wavelengths than does a cooler one.
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True.
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The higher the temperature, the (shorter/longer) the wavelength at which maximum energy is emitted.
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Shorter.
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What is Wien's Law?
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wavelength(max) = 0.0029/T
meters, K |
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What does Wien's law describe?
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The wavelength of maximum energy emission compared to the temperature - w.l.max = .0029 / T
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What is the Stefan-Boltzmann law?
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E = 4 pi R^2 sigma T^4
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E(star1)/E(star2) = ?
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(T1 / T2)^4
assuming equal sizes. else (R1/R2)^2(T1/T2)^4 |
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How many dark lines are seen in the solar spectrum?
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600 dark lines.
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What are the 3 types of spectra?
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Continuous, Absorption, Emission
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What are Kirchoff's Laws?
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Hot opaque body - continuous
cool gas in front of continuous - absorption hot gas - emission |
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What is the photoelectric effect?
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Light kicks off electrons from surfaces.
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What does the energy of a photon equal?
E = ?? |
E = hv
E = hv = h c/ lamda |
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What are the units of Energy in
E = hv = h c /lambda |
Joules [J]
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How many J in an eV?
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1.6 x 10^-19 J / eV
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What was Rutherford's experiment?
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Discovered the nucleus by observing some alpha-particle (He nuclei) bouncing back from gold foil instead of passing through.
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Aborption of a photon produces what kind of spectrum?
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An absorption-line spectrum.
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What is the Rydberg formula?
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1/lambda = R(1/m^2 - 1/n^2)
m=1 lyman m=2 balmer (hydrogen) m=3 paschen m=4 brackett |
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The Lyman series is what kind of radiation?
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Ultraviolet (UV)
Lyman - UV |
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The Balmer series is what type of radiation?
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Visible.
Balmer = Hydrogen = visible |
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The Paschen series is what type of radiation?
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Infrared
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What is the Doppler shift equation?
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delta*lambda / lambda =
v / c v = c delta*lambda/lambda |
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What are the 3 benefits of telescopes?
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Magnification, Brightness, Resolution
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What are the two main techniques used to manipulate light?
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Refraction and Reflection
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The focal length is the distance from the _____ to the _______.
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lens to the focus = focal length
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Magnification = ????
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Focal length of objective / focal length of eyepiece
M = F / f |
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A reflecting telescope with a mirror reflecting to a focus removed from the tube is _____________
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Newtonian focus
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The un-manipulated focus of a reflecting mirror is the __________
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prime focus
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A reflecting telescope with a mirror pointing back through the primary mirror is ______________
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Cassegrain focus
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The light gathering ability of a telescope is proportional to what characteristic?
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The Radius^2 squared
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The radius of "what" affects the light gathering ability
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The objective lens or the primary mirror
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What is the equation for the resolution of a telescope?
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alpha = 2.1x10^5 lambda / D
alpha in arcseconds D is the diameter of the telescope |
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When different wavelengths are brought to different focal points, it's called ______________
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Chromatic aberration.
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How can you minimize chromatic aberration?
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Add different materials and shapes together.
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Chromatic aberration affects what kinds of telescopes?
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Refracting telescopes
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What is the problem called with different reflections being brought to different focal lengths?
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Spherical aberration
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How can you minimize spherical aberration?
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Parabolic mirrors
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How much bigger is the Sun than the Earth?
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100 X bigger
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How many times as massive is the Sun than the Earth?
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A million times as massive
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What is the surface temp of the sun in degrees F?
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10,500 degrees F
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How long does the sun take to rotate?
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1 month
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What are the 3 layers of the solar atmosphere, bottom to top?
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Photosphere, Chromosphere, Corona
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T/F the photosphere is a physical boundary on the sun.
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False- it is an optical boundary
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What produces the sharp edge of the sun?
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The absortion of light (photons) by H- molecules
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What is the height of the photosphere (in km)?
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the photosphere is 400 km high
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What the surface temp of the photosphere in K?
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5,800 K
minimum = 4500 K |
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The surface of the photosphere is covered with _________
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granules
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Why is the edge of the sun dimmer?
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Limb Darkening, dimmer light comes from the cooler, higher deepest region visible on the edges
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How big is a granule?
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Size of Texas + Oklahoma
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What's the temp like on a granule?
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Centers are 50-100 K hotter than the edges
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How long does a granule last?
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8 minutes
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What causes the motion of hot gas rising and cooler gas sinking around the edges of granules?
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Convection
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Where was Helium first discovered?
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In the chromosphere of the Sun during a solar eclipse
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What is the height of the chromosphere (in km)?
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2000 - 3000 km
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What is the temp of the chromosphere?
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4500 K - 10,000 K
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What are the surface features of the chromosphere?
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Spicules
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How tall are spicules?
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As much as 10,000 km high
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How hot is a spicule?
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The temp quickly rises to 1,000,000 K
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How long do spicules last?
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About 15 min.
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How many spicules exist at a given time?
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About 300,000
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What is the height of the corona?
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Millions of kilometers
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What is the temperature of the corona?
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Millions of K
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What heats the corona?
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Magnetic Fields
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How is the corona best viewed?
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In the X-ray during a solar eclipse
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The solar wind's interaction with the Earth's atmosphere creates ________
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Aurora
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Why aren't there eclipses all the time?
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Because the moon's orbit is angled to the ecliptic by 5 degrees
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What are the three types of phenomena on the active sun?
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Sun spots, Prominences, Flares, Coronal holes
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What is the phenomenon in the photosphere?
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Sunspots
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What is the phenomenon in the chromosphere?
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Prominences
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What is the temperature of a sunspot relative to the surface?
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1500 K cooler than the surface
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How long does a sun spot last?
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About 2 months
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Do sunspots like grouping or being isolated?
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Groups of 2-20
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Are sunspots usually bigger than Earth?
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Yes
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What type of rotation does the sun have?
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Differential rotation
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What is the day of the sun at these latitudes: equator, 40 degrees, 80 degrees
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equator - 25 days
40 deg - 28 days 80 deg - 36 days |
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How long is the average solar cycle?
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11 years
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During the course of a sun spot cycle, regions of sunspot occurrence move:
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equatorward, moving from 30 degrees to 10 degrees
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The curving loops of promininces are anchored by what?
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Differing magnetic poles
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Prominences are associated with.....
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Sun spots
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How long do prominences last?
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A few hours to a few months
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Coronal holes are best seen how?
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in X-rays
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How much energy is in a solar flare?
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Millions of H bombs
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What was the Maunder minimum?
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From 1645 to 1715 there were NO SUNSPOTS!
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