Astronomy

Solar system models: Geocentric Earth centered system developed by Ptolemy Was accepted until 1960s heliocentric sun centered system developed by Copernicus Modern understating of the structure of the universe Celestial objects- objects observed in the sky during the day or night. (Planets,Sun,Moon,Stars...) Constellation- A group of stars that make identifiable pattern in the sky Rotation: A spinning about the North and South axis Evidence: The apparent daily counter- Clockwise motion of celestial objects around Polaris (north star) is because of Earth's rotation toward the east. (Rate=15º per hour) Solar day- The amount of time required for the Earth to rotate from one noon to the next 15ºX24 hours=360º Coriolis Effect: <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Horizontal deflection undergone by all moving materials on the Earth's surface <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Northern Hemisphere- Deflected to the right (clockwise) <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Southern Hemisphere- defected to the left(counter clockwise) <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Foucault Pendulum: <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">An experiment to demonstrate the rotation of the earth <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Revolution: <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">A slightly elliptical orbit around the sun (counter clockwise) <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">365.25 days for one revolution <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Evidence: <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Seasonal change of the constellation <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">The solar diameter varies in a cyclic patter <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Perihelion- sun is the largest occurs in the N.H winter (shortest distance between the Earth and sun) <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Aphelion- Smallest occurs in the N.H summer(Largest distance between the Earth and Sun) <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Seasons: <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">the earth's tilt is 23.5º <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Parallelism of the Earth's axis- the earth axis remains parallel throughout its revolution around the sun <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Local Noon- when the sun reaches its maximum altitude <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Zenith- the point directly overhead <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">**The suns rays can only be directly overhead at solar noon between the tropics <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">(23.5º N or S of the equator) <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Equinox- the sun is in the Zenith position at the equator (March 21st and September 21st) <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Summer Solstice- The sun is in the Zenith potion at the tropic or caner <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Longest Daylight of the year in the northern hemisphere <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Winter Solstice- the sun is in the zenith position at the tropic of Capricorn (December 21st) <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Shortest daylight of the year in the northern hemisphere <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">The planets and the Solar system <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Terrestrial (inner) planets <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Mercury, Venus, Earth, Mars <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Consists of a rocky crust, a Dense mantle layer and a very dense core <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Average density, silicone, oxygen and other heavy elements <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">The asteroids that orbit between Mars and Jupiter divide the two groups <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Jovian (outer planets) <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Huge, Gaseous and much less dense <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Hydrogen and helium <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Have ring systems <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Consist of many particles in independent orbits around the planet <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Meteoroid- A rock or an icy fragment traveling in space <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Meteor- the light made by a meteoroid as it passes through Earth's atmosphere <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Meteorite- part of a larger meteorite that survives its trip through the atmosphere and strikes Earth's surface <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">93% are stone (resemble Earth's dark igneous rocks but includes 10-15% iron) <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Irons(85-95% iron the rest is nickel <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Stony- irons rare mixture of stone and iron <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">The most abundant source of meteorites is the antarctic ice cap <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Stars and Galaxies: <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Distance between the Earth and sun is a 150 million KM <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">150 mil. km= astronomical unit (AU) <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Light year (LY)=9.5X10 KM/YR <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">distance that a ray of light travels in one year <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Physical properties <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Size- range from smaller than Earth to 2000X the diameter of the sun <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Density- differs greatly <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Mass- most stars are fairly close to the sun <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Color- depends on the surface temp. <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Red-Cooler <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Blue- Hotter <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Elements- contain mainly helium and hydrogen <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Luminosity- true brightness of a star which depends only upon the size and temperature of a star <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Absolute Magnitude- express luminosity of stars as if they were seen from the same distance <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Origin of a star <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Stars form from dense clouds of gas and dust <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">An outside force triggers the attraction of gravity causing particles to move towards each other <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Temperature increases as the area contracts <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">If the cloud is large enough parts of it will start to glow <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Protostars- Large glowing cloud sections <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Contractions continues protostars become hotter and brighter <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">The Center becomes so hot fusion begins (hydrogen Nuclei untie to form helium <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Red giants and super-giants <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Star loses stability <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">The star gets so hot it causes the outer layer to expand, enlarging its surface area <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">White dwarfs: <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Most of the fusion used up <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Super-Nova <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">As the star core cools it begins to collapse <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Pressure and temperature rise dramatically <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">The star explodes violently <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Black holes <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Gravitational forces are so powerful that even light can not escape <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Galaxy: a group of millions or billions of stars held together by gravity <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">We belong to the milky way galaxy <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Spiral- central lens shape and spiral arms which usually contain millions of stars as well as dust and gas <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Big band hypothesis <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Universe was packed into one dense sphere of hydrogen <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">15 billion years ago the mass exploded forming an expanding cloud <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Cloud parts condensed into galaxies <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Red shift- evidence that the universe is expanding <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Earth's moon revolves in an elliptical orbit around the Earth <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">A) revolution 27.33 days <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Perigee- moon nearest the Earth <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Apogee- moon farthest the Earth <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">Phases of the moon <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">two reasons <span style="color: #de60e4; font-family: Verdana,Geneva,sans-serif;">The mood is seen by reflected light <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">The mood is in orbit around the Earth <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Full moon <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Waning Gibbous <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Last Quarter <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Waning Crescent <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">New moon <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Waxing crescent <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">1st quarter <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Waxing Gibbous <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;"> <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Lunar month- the time from one new moon to the next <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Revolution=29.5 days <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Eclipse <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Umbra- the total shadow <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Surrounding the umbra <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Lunar eclipse- occurs when the moon passes into Earth's umbra <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Only occurs at the full moon phase <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">The moon's and Earth's orbit are inclined to each other by 5* so a lunar eclipse does not occur every month (1 per year) <span style="color: #ff0076; font-family: Verdana,Geneva,sans-serif;">Solar eclipse- occurs when the moon's umbra reaches Earth's surface <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Locations on the Earth's surface within the umbra experience a total solar eclipse <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Locations in the penumbra receive a partial solar eclipse <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Can only occur at the New moon phase <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Solar eclipse per year, however at a given location 1 year every 300 years <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Tides- The daily rise and fall of the ocean waters <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">*Gravity is stronger when objects are closer together <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Direct- the water on the side of the Earth nearest the moon is pulled by the moon more strongly than Earth itself causing a bulge <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Indirect- the Earth is pulled away from the water and the far side leaving a bulge of water <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">The tides change every 6 hours and 12 minutes (50 minutes later than the previous day) <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Spring tides- Occur during full and new moons when the sun moon and Earth in line <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">The sun and moon's tide making effect combine <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Higher high tides are lower low tides <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Neap tides- occur during the quarter phases when the sun and the moon are at 90º <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">The sun is opposing the mood <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">The high tides are not very high <span style="color: #28c7ee; font-family: Verdana,Geneva,sans-serif;">Tidal effects are greater when the moon is at perigee