ASTR 1010 1st EditionExam # 1 Study Guide Lectures: 1 - 8Lecture 1 (August 26)Introduction to the Chapter 1, Part 1What is our cosmic address? What is the largest and smallest part of it? Our cosmic address:- Supercluster > local Cluster/Group > Milky Way Galaxy > Solar system > EarthThe largest part is the supercluster, while the smallest part is the Earth.Lecture 2 (August 28) Introduction to Chapter 1, Part 2How is a star born?A star is born when gravity pushes enough material into a cloud that forms a hot, hard center that generates energy from nuclear fusion. The star lives as long as the energy from the fusion continues and dies when it runs out. A star throws its contents back into space, but a massive star becomes a supernova before dying out. What remains is then recycled into galaxies.What is an AU? What is Earth’s average orbital speed?An astrological unit (AU) is Earth’s average orbital distance. It is equivalent to 150 million kilometers (93 million miles). Earth races around the sun at an average of 100,000 km/h.Where does Earth’s axis point?Earth is tilted on its axis at a 23.5˚ angle perpendicular to the ecliptic plane. It points toward Polaris, “the North Star.”How long does it take our solar system to complete an orbit around the Milky Way?Our solar system completes one orbit around the Milky Way once every 230 million years, moving at a speed of 800,000 km/hr. Lecture 3 (September 2) Motions and Coordination SystemsDefine celestial sphere, Ecliptic, zenith, meridian, and circumpolar.Celestial sphere: an imaginary sphere of which the observer is the center and on which all celestial objects are considered to lie.Ecliptic: the path the sun follows as it appears to circle around the celestial sphere. It crosses the celestial equator at 23 ½ ˚ angle due to the tilt of Earth on its axis.Zenith: From wherever you are standing, perpendicular to the ground and directly upward in the skyMeridian: a North South arch that passes through the zenith and connects the north and south celestial poles.Circumpolar: stars that remain perpetually above the horizon, circling counter-clockwise around the north celestial pole. Circumpolar stars on the south celestial pole never rise above the horizon each day.Lecture 4 (September 4)Seasons and Moon PhasesDescribe each Solstice occurrence.The Summer Solstice occurs around June 21st. Northern Hemisphere is dipped almost directly toward the Sun.The Winter Solstice occurs around December 21st. Northern Hemisphere is almost pointed directly away from the Sun.The Spring Equinox occurs around March 21st. Northern Hemisphere goes from being tipped slightly away from the sun to being directly pointing at the sun.The Fall Equinox occurs around September 22nd. Northern Hemisphere first starts to be tipped away from the sun.What is the difference between Solar and Lunar Eclipses?A lunar eclipse happens when Earth’s shadow falls onto the moon, while a solar eclipse is when the moon blocks the view of the sunLecture 5 (September 9)Orbital TheoriesWhat is the difference between the geocentric and heliocentric theory? Who is credited for each?The geocentric theory states that the Earth is the center of the universe. Ptolemy is credited for it. The heliocentric theory states that planets orbit the sun. This is usually credited to Copernicus.Lecture 6 (September 11)Kepler’s Laws of Planetary MotionWhat are Kepler’s Laws?1. The orbit of planets are an ellipses with the sun at the focus.2. The radius vector connecting a planet and the sun will sweep out equal areas of equal intervals of time.3. More distant planets orbit the sun at slower average speeds, obeying the mathematical relationship, p2=a3, where p is period in years and d is distance in Astrological Units, which is the average distance between the sun and Earth (1 AU = 93 million miles).Define Perihelion and Aphelion. Where is orbital speed fastest?Perihelion: the point in the orbit of a planet, asteroid, or comet at which it is closest to the sun. Orbital speed is fastest.Aphelion: the point in the orbit of a planet, asteroid, or comet at which it is closest to the sun. Orbital speed is slowest.Lecture 7 (September 16)Newton’s Laws of MotionWhat are Newton’s Laws?1. Any object in motion will stay in motion until acted upon by an outside, unbalanced force. 2. Force = mass x acceleration3. Every action has an equal and opposite reaction.Lecture 8 (September 18)Gravity & Astronomical FormulasWhat is gravity?Gravity: the force that attracts a body toward the center of the earth, or toward any otherphysical body having mass. What is the acceleration of gravity?On Earth, g= 9.8ms2. Speed increases with each second of falling. What is momentum?Momentum = mass x velocityDefine Sidereal Time, Hour angle, declination, and Right Ascension.Sidereal Time: the hour angle of the vernal equinox at that locality: it has the same value as the right ascension of any celestial body that is crossing the local meridian at that same momentHour angle: the angle between the celestial meridian of an observer and the hour circle of a celestial object measured westward from the meridian.Right ascension (RA) and declination (DEC) define the position of a celestial object.List formulas to find hour angle, location of star in relation to east or west, sidereal time, and if astar is circumpolar.To find Hour Angle (HA): 360˚ = 24 hours 15˚ = 1 hour 1˚ = 4 minutesTo find of the sun/moon is in the east or west.0 h ≤ HA ≤ 6h, it is in the West.18h ≤HA ≤24h, it is in the East.To find Sidereal Time (ST)ST = RA + HATo find if a star is circumpolar90˚ - Latitude = Dec circumpolar (n)Every star from n to 90 is circumpolar. Any star –n and below will not be