Astronomy Ch.1-4 Test

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Aristotle claimed the earth was ________, but that the heavens were _______. Imperfect, perfect
What is one AU? The distance from the earth to the sun (approximately 150 million km)
What is one light year? The distance light travels in one year
What is today's definition of a constellation? Well defined regions of the night sky
The Big Dipper is an example of a(n) _________. Asterism (portion of a constellation)
What is the Celestial Sphere? The appearance of the the stars from earth.
The ______ star is the brightest star in a constellation. alpha
The brightest stars are part of the ________ magnitude, and the the faintest stars visible to the naked eye are part of the _______ magnitude. first, sixth
First magnitude stars are _______ times brighter than sixth magnitude stars. one hundred
Stars become _______ times brighter with each increase in magnitude. 2.5
What is the relationship between magnitude and brightness of a star? The smaller the magnitude, the brighter the star.
What is a zenith? The highest point in the celestial sphere
What is a nadir? The lowest point in the celestial sphere
What is the celestial equator? Earth's equator projected out into space
What is the celestial north pole? Earth's north pole projected out into space
The distance between stars is typically measured in ________. degrees
What is latitude? The angle from the horizon to the celestial north pole
What is altitude? The number of degrees above the horizon
What is azimuth? The number of degrees on the horizon
What is meant by the term circumpolar? Stars that never set and are constantly rotating around celestial north.
What is the name of the apparent path of the sun? The ecliptic
Seasons are caused by the ________. angle of incidence
What does the term "perihelion" mean? It is when the earth is closest to the sun.
What are the astronomical influences on the seasons? Eccentricity, precession, inclination of the Earth's axis, and Milankovitch hypothesis (changes in all 3 = long-term global climate change).
It takes 29.53 days for the moon to go through one _______ period. synodic
Because the moon is __________, only one side can ever be seen from earth. tidally-linked
The _______ is the DARKER shadow of earth. umbra
The _______ is the LIGHTER shadow of earth. penumbra
A(n) _________ shadow is necessary for a total lunar eclipse. umbra
In a(n) ________ eclipse the moon is covered. lunar
In a(n) ________ eclipse the sun is covered. solar
The _______ is a layer of atmosphere of the sun just outside of the photosphere. chromosphere
The _____ is the glare the comes off of the sun during solar eclipses. corona
_________ jump from the sun and back again. Prominences
________ occurs when the moon is CLOSEST to the earth. Perigee
________ occurs when the moon is FURTHEST from the earth. Apogee
A(n) ________ solar eclipse occurs when the moon doesn't completely cover the sun. annular
Who accurately calculated Earth's radius for the first time? Eratosthenes
What theory has the planets on epicycle tracks? Ptolemy
Copernicus came up with the idea of a ________ universe. heliocentric
The apparent backward motion of Mars from earth is an example of ________. retrograde motion
Who was a supernova that overruled Aristotle's theory of a perfect universe? Tycho Brahe
Who hired Johannes Kepler? Tycho Brahe
Kepler said that planets have _____ orbits and move in _______ motion. elliptical, non-uniform
What were Kepler's three laws? 1.) Planets move around the sun.2.) The sun sweeps over equal areas in equal amounts of time.3.) A planet's orbit squared is proportional to its distance from the sun cubed. P(squared) = a(cubed)
Galileo founded science that was purely based on ________. observation
True of False: Galileo invented the first telescope. False, but he did greatly improve upon it.
What important discovery about Jupiter did Galileo make? Its moons
What did Galileo see for the first time on Saturn? Its rings
Galileo noticed _______ on the moon. surface structures
Galileo discovered _______ on the sun, proving it is not perfect. sun spots
What did Galileo use to prove a heliocentric universe? The phases of Venus