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48 terms

Astronomy Quiz 1

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Milky Way
Our galaxy which contains 200 billion stars
Light Year
the distance light will travel in one year
constellations
star pictures drawn in the sky by ancient civilizations. there are 88 in all
Sirus
brightest star in the sky
Asterisms
things that look familiar but are part of a constellations and not one themselves. Examples= big and little dipper
Celestial Sphere
A sphere that encompassed the globe where every star was plastered to that and it was believed that this sphere moved. This ancient belief was an attempt to understand the night sky and which doesn't really exist
Rotate
Earth rotates on its axis
Revolve
earth revolves around the sun
Celestial Poles
Projecting the earth's coordinates into the sky (latitude and longitude)
Alpha and the greek alphabet
The brightest star in the constellation is always referred to as alpha followed by beta etc.
Latitude
horizontal coordinates that are added 10 degrees when going north about the equator where its zero and subtract 10 degrees going south
Longitude
Verticial coordinates
Prime Merdian
The "zero line" in longitude which goes through Greenwich, England
Latitude in the sky=
Declination or DEC
prime meridian=
vernal equinox
longitude=
referred to in hours called right ascension (RA)
Solar day
a day according to the sun which equals 24 hours. Longer because it takes into account that we are revolving around the sun as well rotating on earth's axis. this difference is one of 4 minutes
Sidereal Day
a day measured by the stars= 23 hours and 56 minutes which is the true measure of rotation
Reason for seasons
= the tilt of the earth's axis
winter solstice (December 21st)
when the sun is tilted fartherest away from the sun. This produces the shorest days and nights
Summer solstice (June 21st)
when the sun is in the sky for the longest and at the highest
why is it hot in the summer?
because the sun is high in the sky and stays out longer
Cold in winter?
because the sun is low in the sky and stays out for the shortest period
Vernial equinox
spring time occurs on march 21st and the sun is in the sky equal amount of time that it isn't
Automnal equinox
fall time occurs on september 21st
Earth's tilt
21.5 degrees
Ecliptic
path way of the sun which passes through 13 costallations which is where we get our zodiac signs from.
Precession
sun moves this way in the sky as well which is a wobble of the earth much like a spinning top. this wobble that has taken place over 26,000 years which has made our zodiac sign change and it is not what we thought it was when it was made.
Triangulate ideology
how we measure "x" a method to measure the distance of the stars from earth
Parallax
measure stars by using the baseline of the Earth. Tells us how much something is from us in the sky . has to be close in order to work. if there is a small parallax than the object is far away. if large parallax than the object is close
Aratosthenes
Greek scientist who found the cirumference and radius of the earth
Prograde
traveling west to east
retrograde
traveling east to west
Aristotle
believed in geocentric (earth centered) universe. Also believed in uniform circular motion orbiting the earth in a uniform motion.
Ptolemy
used epicycles and defferents believed in geocentric system
Deferents
the orbit path around the earth
epicycle
the planets orbit around themselves to explain the movements of the planets and why they move backwards and change brightness
Occam's Razor
the simplest explanation is almost always the correct explanations
Aristarchus of samus
he believed that the sun at the which is called heliocenteric and that the earth is on an axis
Nicholas cupurinus
rediscovered aristarchus of samus ideas
Cupurincan revolution
realization that earth is not the center of the univerese and everything traveled around the sun
Retrograde motion
when we pass planets that are further away than us on their own orbit that seem to "back-up"
Galieo Galei
"father of experimental science" conducted experiments through a telescope he created
Kepler
A german scientist who created the Law's of planetary Motion
Astronomical unit (Au)
the distance between the earth and the sun. if you know how fast a planet is going around the sun you can determine how far away it is
Sir issac newton
three laws of motion and law of gravity= newtonian mechanics
Force
As mass goes up accleration goes down; as mass goes down accleration goes up
accleration
rate of change of the velocity of an object speeding up, slowing down or change of direction