Karteikarten
Astronomy basics: celestial sphere, sky motions, moon phases
Karten in diesem Stapel (134)
- 1what is astronomyit is the oldest of all sciences, a natural science, and is the study of the universe
- 2what was the earliest description of the universe based onimagination and mythology, not the scientific method
- 3define theorya framework of ideas and assumptions used to explain a set of observations
- 4when did the power of myth diminishwhen logic started to grow
- 5what elements compose a theory-can be invalidated by a single wrong prediction
-must be testable
-must continually be tested
-should be simple - 6what is the scientific methoda process combining both theoretical reasoning with experimental testing.
In order to observe phenomena one must formulate a hypothesis, test and modify the hypothesis, and make a theoretical model for its theory - 7what is the most important take away of learning the scientific methodteaches us to think critically
- 8Astronomy = science of __________superlatives
eg. biggest, hottest, coldest, fastest, furthest - 9what is a simple definition of a solar systemplanets orbiting about stars
- 10what is a simple definition of a galaxysystems of billions of stars orbiting around a centre
- 11what is the celestial spherean imaginary sphere in which the center is the observer and the sphere is composed of things in the celestial (eg. stars)
- 12how many regions is the sky divided up into and what are they called88 and are called constellations
- 13what is the celestial polesthe points where the earth's axis intersects the celestial sphere
- 14what is the celestial equatormidway between the north and the south pole
- 15what is a sign that earth is roundour view of the sky changes with latitude
- 16what is Zenithan imaginary point directly above the observer on the imaginary sphere
- 17any model/theory of the Universe must explain what observations-sky rotates
-Sun, moon, stars rise in the east and set in the west
-some stars never set
-pole star remains fixed
-stars fixed with respect to each other
-moon moves 12degrees/day (rises 50 minutes later each night) - 18what is the horizonthe line where earths surface and the sky seem to meet
- 19what is the northstarPolaris
- 20what is a sidereal daythe time needed between successive risings of a given star
- 21what is a solar daythe period of time between the instant when the sun is directly overhead to the next time the sun is directly overhead
- 22what is the eclipticthe apparent path of the sun on the celestial sphere
- 23what moves along the eclipticsun, moon, and planets
- 24describe the ecliptic-confined to a narrow path
-12 constellations along the ecliptic are known as the Zodiacal constellations
-planets move with respect to fixed stars
-ecliptic plane and celestial equator form an angle of 23.5degrees - 25what is the greek word for planetwanderer
- 26what are equinoxes2 points where the earth's rotation axis is perpendicular to the earth-sun line. and occur on March 21 and September 21
- 27what happens during the autumnal equinoxthe sun crosses from the northern into the southern hemisphere
- 28what happens during the vernal equinoxthe sun crosses from the southern hemisphere into the northern hemisphere
- 29what are the phases of the moonnew moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, waning crescent
- 30describe aristotle384BC - 322BC
-taught that circular motions are the only natural motions in the universe
-earth is at the center of the universe.
-first to adopt physical laws and show why that the universe works as it does
-first real example of the scientific method (eclipse- and how earths shadow is shown on the moon) - 31what is penumbrasun is partly visible, partial eclipse is seen
- 32what is umbrasun completely obscured, total eclipse seen
- 33what is the angle of the moons orbitslightly inclined to the ecliptic (at an angle of 5.2degrees)
- 341degree = ___60' arcminutes
- 351' = ___60" arcseconds
- 36what is parallaxa mathematical way to measure distances to objects, or sizes of objects
- 37what is the universeit is the totality of all space, time, matter, and energy
- 38what is the speed of light300,000 km/sec
- 39why was the unit light year createdto help astronomers describe immense distances
- 40what is a theoretical modeltaking something too huge or too little to be observed and creating either a smaller or bigger version of it
- 41define pseudosciencea collection of beliefs and/or practices mistakenly regarded as being based on the scientific method
- 42what is Occam's razorwhen you have two competing theories that both explain the facts and make the same predictions, then the simpler one is better
- 43describe Aristotle' first use of the scientific methodAristotle observed how during a lunar eclipse, earth casts a curved shadow onto the surface of the moon. He theorized that earth must be the cause of the shadow, thus making the earth round. He then predicted that all future lunar eclipses would show earths shadow to be curved
- 44how did constellations help out ancient societieswell such as the North star guided travellers in the right direction. and other constellations served as a calendar to predict planting and harvesting seasons
- 45define diurnal motionapparent daily motion of the stars caused by earths rotation
- 46what is the latin name for starsidus
- 47which is longer, a sidereal day or a solar daythe solar day is 3.9 minutes longer
- 48why is there a sidereal day and a solar dayit is because the earth not only rotates along its axis but also rotates around the sun
- 49what is the brightest starSirius or the Dog star
- 50what is the summer solsticepoint on the ecliptic where the sun is at its northernmost point above the celestial equator
- 51what is the latin word for sunsol
- 52what is the longest day in the northern hemisphereJune 21
- 53what is the shortest day in the southern hemispherejune 21
- 54what is the winter solsticepoint on the ecliptic where the sun is at its southernmost point below the celestial equator, December 21
- 55when is the shortest day in the northern hemisphereDecember 21
- 56when is the longest day in the southern hemisphereDecember 21
- 57why is there a difference in temperature in the seasons- more sun in the summer means more heat directed on earth
-when the sun is high up in the sky its rays are more concentrated - 58what does equinox mean in latinequal night
- 59what is a tropical yearthe time interval between one vernal equinox and the next
- 60define precessionthe slow change in the direction of the rotation axis of a spinning object, caused by some external gravitational influence
- 61what is the cause of precession on earthit is caused by the torques (twisting forces) on earth due to the gravitational pulls of the moon and the sun
- 62how long is a complete cycle of precession26,000 years
- 63what is a sidereal yearthe time required for earth to complete one orbit around the sun relative to the stars
- 64why is a sidereal year longer than a tropical yearearths precession
- 65how long does it take for the moon to undergo a complete cycleroughly 29.5 days
- 66whats the difference in a waxing and waning moona waxing moon seems to grow and a waning moon seems to shrink
- 67what is a sidereal month and how long is itthe time required for the moon to complete one full orbit around the celestial sphere. around 27.3 days
- 68what is a synodic month and how long is ittime required for the moon to complete a full cycle of phases. around 29.5 days
- 69what is an eclipsewhen one body passes in front of another, so that the light from the occulted body is blocked
- 70what is a lunar eclipsewhen the moon passes through the shadow of the earth, temporarily darkening its surface
- 71what is a partial lunar eclipsebasically an imperfect eclipse, because its hard for the shadow to completely cover the moon
- 72what is a solar eclipsewhen the moon passes directly in front of the sun
- 73what is an annular eclipsewhen the moon is far enough away from earth that a ring of the sun outlines the moon
- 74what are nodestwo points on the moon's orbit when it crosses the ecliptic
- 75what is the line of nodesintersection of the plane of the moon's orbit with the earths orbital plane
- 76what is eclipse seasontime of the year when the moon lies in the same plane as earth and sun, so eclipses can occur
- 77what is an eclipse yeartime interval between successive orbital configurations in which the line of nodes of the moon's orbit points toward the sun
- 78whats the difference between a solar and lunar eclipsea lunar eclipse is when the earth stands inbetween the moon and sun. a solar eclipse is when the moon stands between the earth and sun
- 79what is the saros cycletime interval between successive occurrences of the "same" solar eclipse, equal to 18 years and 11.3 days
- 80define parallaxthe apparent motion of a relatively close object with respect to a more distant background as the location of the observer changes
- 81when do you have a large parallaxwhen the object is closer to the observer
- 82describe Eratosthenes(276-194BC):
in about 200 BC he used simple geomtric reasoning to calculate the size of our planet - 83who was the first person to realize the planet is curvedAristotle
- 84what are the inferior planetsMercury and Venus
- 85what are the superior planetsMars, Jupiter, and saturn
- 86what is inferior conjunctionwhen an inferior planet is closer to earth and moves in a retrograde motion
- 87what is superior conjunctionthe planet is farthest from earth and moves in a prograde/direct motion
- 88what is oppositionorbital configuration in which a planet lies in the opposite direction from the sun
- 89when do superior planets exhibit retrogradewhen they are at opposition
- 90when are the superior planets the brightestat opposition
- 91when are the inferior planets the brightestfew weeks before and after inferior conjunction
- 92who first came up with the geocentric theoryPlato
- 93what was aristotle's geocentric model likeit had earth at the center, with the planets and the sun revolving around it in a perfect circular motion
- 94what was ptolemy's geocentric modelit had earth at the center, with the planets and sun revolving around it in an orbit known as a deferent, as well as a smaller orbit of just the planet called the epicycle. He had used no fewer than 80 distinct circles
- 95who first proposed the heliocentric modelAristachus
- 96who rediscovered Aristarchus' heliocentric modelNicolaus Copernicus
- 97what did Aristarchus' model have different from the originally proposed heliocentric modelthat the earth spins on its own axis and orbits around the sun, and the moon orbits earth
- 98what are the foundations of the Copernican revolution1. earth not center of everything
2. center of earth is of gravity & the lunar orbit
3. all planets revolve around sun
4.stars are far from the sun
5. apparent movement of stars is caused by earth's rotation
6.apparent movement of sun is due to earth's rotation
7.retrograde motion of planets is due to earth and planets motion around the sun - 99whose books was bannedCopernicus' and Galileo's
- 100who invented the telescope and when was it inventedHans Lippershey - 1608
- 101describe Galileo(1564-1642)
built his own telescope
heavily criticized by the Church - 102what observations did Galileo make with his telescopemoon has mountains and valleys
sun has sunspots and rotates
venus has phases
jupiter has moons - 103who is the father of experimental scienceGalileo
- 104who published Dialogue on the 2 Chief World systemsGalileo
- 105describe the Dialogue on the 2 Chief World systemshad 3 characters... Salviati, Sagredo, Simplicio
- 106who was sentenced to house arrestGalileo
- 107who was the first modern observerGalileo
- 108what was Tycho Brahe known formade multiple observations of same objects to improve accuracy
- 109why did Tycho Brahe reject the heliocentric modelcouldn't find evidence of the earth moving
he could not detect parallax
religious perspective - 110Describe Johannes Kepleraccepted heliocentric model
worked as Tycho's assitant - 111what did Johannes Kepler do after Tycho's deathDetermined the orbit of Mars, which he discovered to be an ellipse
- 112how far off were Tycho's observations8' (8 arc minutes)
- 113what are Kepler's 3 laws of Planetary motion1. orbits are ellipses with the sun at one focus
2. A line drawn between the Sun and the planet sweeps out equal areas in equal time (law of areas)
3. P^2 proportional to a^3
P = period, a = semi-major axis
OR
P^2 = ka^3
k = 1 if the object is orbiting the sun, P is in years, and a is in AU - 114define Eccentricitydistance between foci/ major axis
- 115who published the Harmony of the Worlds in 1619Kepler
- 116what is the average distance between the Sun and Earth1 AU
- 117how are the dimensions of the solar system now measuredby using radar
- 118how did Kepler create his 3 lawsfrom empirical/ observational data
- 119what did Issac Newton dodeveloped a deeper understanding of the way all objects move and interact with each other
- 120who published the Mathematical Principles of Natural Philosophy (Principia)Issac Newton
- 121what are the 3 laws of motion1. every object continues in a state of rest or of uniform motion in a straight line, unless it is compelled to change that state by forces impressed upon it.
2. The change of motion is proportional to the force impressed; and is made in the direction of the straight line in which the force is impressed.
3. To every action there is an equal and opposite reaction - 122how do you find the velocityV = d/t
d: displacement
t: time - 123how do you find the accelerationa = Change of V / Change of time
- 124what is an eccentricity of 1a straight line
- 125what is an eccentricity of zeroa perfect circle
- 126when does a planet move the fastestwhen closest to the sun
- 127what two things are needed to describe the size and shape of a planet's orbital pathsemimajor axis and eccentricity
- 128define perihelionthe point of closest approach to the sun
- 129define aphelionpoint of greatest distance from the sun
- 130define inertiathe tendency of an object to keep moving at the same speed and in the same direction unless acted upon by a force
- 131what is the formula to find ForceF = m x a
m: mass
a: acceleration - 132what are the units for accelerationm/s^2
- 133how to measure gravitational forcemass of object 1 X mass of object 2
divided by...
(distance)^2 - 134how to measure the Force between two bodiesF = (Gm1m2) / (r)^2
G: gravitational constant
r: distance
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- Beschreibung
- Astronomy 209 Karteikarten am Ohne Titel, erstellt von Chelsea Scheck am 09/07/2019.
- Erstellt von
- Chelsea Scheck
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