Astronomy Quiz 1
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48 terms
Terms | Definitions |
|---|---|
 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 |
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