The Cosmic Perspective Ch 1-3 Flashcards

Basic terms, historical figures, a few concepts

206487678	astronomy	the scientific study of the universe; It includes the observation and interpretation of celestial bodies and phenomena	0
206487679	retrograde motion	the apparent westward motion of the planets with respect to the stars	1
206487680	astronomical unit (AU)	average distance from the Earth to the sun; 1.5 × 10⁸, or million kilometers	2
206487681	ellipse	has a semi-major and major axis and two foci.	3
206487682	rotation	the spinning of a body, such as earth, about its axis	4
206487683	revolution	the motion of one body about another, as Earth about the sun	5
206487684	precession	a slow motion of Earth's axis that traces out a cone over a period of 26,000 years	6
206487685	perihelion	the point in the orbit of a planet where it is closest to the sun	7
206487686	aphelion	the place in the orbit of a planet where the planet is farthest from the sun	8
206487687	perigee	the point at which the moon is closest to the Earth	9
206487688	apogee	the point where the moon is farthest from Earth	10
206487689	phases of the moon	the progression of changes in the moon's appearance during the month. In order- New moon, waxing crescent, 1st quarter, waxing gibbous, full moon, waning gibbous, 3rd quarter, waxing crescent.	11
206487690	nebula	A cloud of dust, gas or both in space. Where star clusters are formed.	12
206487691	planetesimals	A small, irregular shaped body formed by colliding matter.	13
206487692	Geocentric Model	the model where the planets, sun, and moon orbit Earth	14
206487693	Heliocentric Model	the model where Earth and other planets orbit the sun	15
206487694	Claudius Ptolemy	About 140 AD in the Alexandria • Fit universe to a mathematical model • Geocentric • Uniform circular motion • Epicycles and deferents • Very accurately predicted planet positions (at first)	16
206487695	Nicolaus Copernicus	• Proposed a heliocentric universe • Motivated to reinstate uniform circular motion in its purest form • Retrograde motion was a natural result of the Earth's motion • Needed more epicycles than Ptolemy • Predictions were no better than the Alfonsine Tables • Revolutionized humankind's view of the Earth	17
206487696	Tycho Brahe	• Decades of accurate observations • No parallax for the nova of 1572 • Placed the nova past the Moon • De Stella Nova, made him famous in educated circles • No parallax for stars • Favored the Herakleides cosmology	18
206487697	Kepler law #1	all planets orbit sun in ellipse	19
206487698	Kepler law #2	when a planet is closer to the sun in its orbit, it moves faster	20
206487699	Kepler law #3	p²=a³ when p is an orbital period in yrs, and a is the avg dist. from the sun in AU	21
206487700	Galileo Galilei	-discovered how bodies fell -first to use telescope for scientific purposes -discovered moons are imperfect -discovered Jupiter's moons -claimed discovery of sun-spots (actually Jesuits) -work resulted in Decree of 1616, no one allowed to teach Copernican model	22
206487701	Sir Isaac Newton	-created three laws of motion -invented integral calc	23
206487702	29 ½ days	time from new moon --> new moon	24
206487703	27 1/3 days	days it takes moons orbit around earth	25
206487704	synodic month	new moon --> new moon is called	26
206487705	sidereal month	earth, moon, and star are all aligned	27
206487706	umbra	region where sunlight is completely blocked	28
206487707	penumbra	region where sunlight is partially blocked	29
206487708	meteorite	a meteoroid that actually reaches earth's surface	30
206487710	Lunar Eclipse	the blocking of sunlight to the moon that occurs when Earth is directly between the sun and the moon	31
206487711	Solar Eclipse	occurs when the Moon passes directly between the Sun and Earth and casts a shadow over part of Earth	32
206487712	universe	the total sum of all matter and energy	33
206487713	star	large, glowing ball of gas that generates heat and light via nuclear fusion	34
206487714	planet	In order for an object to be considered a planet it must orbit a star (but neither be a star nor a moon), be massive enough to give it a nearly round shape, and clear the neighborhood around its orbit. If an object meets the first two criteria, but not the third, it is a dwarf planet.	35
206487715	moon	object that orbits planet	36
206487716	asteroid	a relatively small and rocky object that orbits a star	37
206487717	comet	a small, icy object that orbits a star	38
206487718	small solar system body	an asteroid, comet, or other object that orbits a star, but doesn't qualify as a planet or dwarf planet	39
206487719	solar system	a star (or sometimes more than one star) and all the objects that orbit it in its gravitational field.	40
206487720	star system	a star, and any planets or other materials that orbit it	41
206487721	galaxy	A galaxy is a huge collection of stars bound together by gravity at a common center	42
206487722	galaxy cluster	a collection of galaxies bound together by gravity (called a group if small collection, and a cluster if large collection)	43
206487723	supercluster	a gigantic region of space where many individual galaxies are packed closely	44
206487724	observable universe	the portion of the entire universe that can be seen from earth on principle- 14 billion light years in all directions	45
206487726	Planets in order away from the sun	Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and (not really per se) Pluto	46
206487727	Edwin Hubble	1.) Every galaxy is moving away from us. 2.) The further the galaxy, the faster it is moving	47
206487728	constellations	a region of the sky with defined borders	48
206487729	zenith	the point above the observer that is directly opposite the nadir on the imaginary sphere against which celestial bodies appear to be projected	49
206487730	meridian	imaginary line drawn from the horizon due north to due south	50
206487731	azimuth	direction of a celestial object, degrees clockwise from due North, and it's altitude above the horizon	51
206487732	Summer Solstice	June 21	52
206487733	Winter Solstice	December 22, when the sun is at its southernmost point	53
206487734	Spring Equinox	March 21	54
206487735	Fall Equinox	September 22	55
206487736	lunar eclipse	earth lies between sun and moon	56
206487737	solar eclipse	moon lies between sun and the earth	57
206487738	nodes of orbit	where moon crosses elliptic plane	58
206487739	conditions for ellipse	1.) Moon must be fill 2.) Nodes must be aligned	59
206487740	Types of lunar eclipes	1.) total- moon passes through umbra 2.) partial- part of moon passes through umbra 3.) penumbral- moon passes through prenumbra	60
206487741	Types of solar eclipses	1.) total- occurs in area that falls in the moon's umbral shadow 2.) partial- occurs in the area falling the the penumbral shadow 3.) annular- occurs when the umbral shadow doesn't reach the earth, where the umbral shadow would've hit	61
206487742	stellar paralax	when stars shift back and forth against back-ground of distant stars	62
206487743	metonic cycle	19 year cycle on which the dates of the lunar cycle repeat, Named for Greek astronomer Meton	63
206487744	light year	distance it takes light to travel in one year (10 trillion KM)	64
206487745	tilt of earth's axis perpendicular to elliptic plane	23.5 degrees	65
206487746	order of magnitude estimate	estimates to nearest power of 10	66
206487747	saros cycle	occurs every 18 years and 11 1/3 days. combination of changing eclipse seasons and lunar cycles.	67
206487748	Pythagoras	• Earth a sphere • Sun, Moon and planets on wheels • The music of the spheres • Only the master could hear the music	68
206487749	Philolaus	-first to suggest earth moved -believed earth moved around central fire	69
206487750	Aristarchus	heliocentric model	70
206487751	Herakleides	planets orbit sun, sun orbits earth (couldn't see stellar parallax)	71
206487752	Plato	-Taught observation is useless -heavens were perfect, planets spheres, motion was uniform	72
206487753	Aristotle	-taught earth didn't move -heaven and earth different spheres	73
206487754	Ptolemy	-geocentric solar system -made accurate predictions of planets for some time	74
206487755	5 Obstacles to Astronomy Copernican Revolution	-Separate earth and heavens -geocentric dogma -dogma of circular motion -science w/o math -misunderstanding of motion	75
206487756	Copernican Revolution	Heliocentric model	76
206487757	Newton's Three Laws	1. A object in motion tend to stay in motion unless acted on by another force. 2.f=ma 3. Every action has a equal and opposite reaction	77
206487758	Halley	• Actually paid for the publication of the Principia, Newton's book on physics which contained the law of gravity. • Showed that the orbit the comet of 1682 was the same as the orbit of the comets of 1531 & 1607	78
206495122	small angle formula	angular size= physical size(360/2πdistance)	79