Final Exam Review
Final Exam Review astronomy 113
Popular in Intro to Astronomy
Popular in Department
This 3 page Study Guide was uploaded by eriley2 on Tuesday April 26, 2016. The Study Guide belongs to astronomy 113 at George Mason University taught by Pesce in Winter 2016. Since its upload, it has received 49 views.
Reviews for Final Exam Review
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 04/26/16
1. Cosmic Microwave Background Radiation is the thermal radiation left over from the big bang. It is essentially the oldest light in the universe. 2. The basic stages of the sun’s life so far: a. Gas cloud (Nebula) b. Protostar c. Hydrogen fusion begins d. Main Sequence star 3. Measurements of astronomical distances a. AU (Astronomical Unit) distance from Earth to the Sun. 149 million kilometers b. Light year, distance time takes to travel one year in a vacuum. c. Parsec, amount that a star moves as earth goes from one side of the sun to the other. Approximately 3.26 lightyears. Multiples of parsecs are often used, such as kiloparsec (kpc) or megaparsec (mpc) 4. v r H *OD thus v = ([60km/s]/Mpc) * 100 Mpc r v r 6000 km/s 5. If you triple the distance from a light source, the brightness is decreases to 1/9 6. The interstellar medium is the gas and dust that lies between stars 7. Quasars consume gas and dust they accrete, with some of the largest quasars consuming the equivalent of 600 Earths per minute. 8. A star spends most of its life on the main sequence. 9. A galaxy is at one billion light years away. This can mean a number of things: That we are seeing it as it was one billion years ago That it is 306 Mpc away 10.Considering the scale of OBAFGKM, the difference between an F-type star and M-type star would be thus – a. The M type would be significantly smaller b. M type would be significantly cooler c. M type is red, F type would be yellow-white 11.Dark matter is thought to make up the vast majority of the mass of the Universe. The actual nature of dark matter is currently unknown. 12.Quasars, radio galaxies and Seyfert galaxies are all examples of galaxies with active galactic nuclei. 13.The mass of a star can be measured by: a. Luminosity and temperature b. Orbital speeds and periods of stars in binary systems 14.Dark matter and energy makes up the largest fraction of the mass/energy budget of the universe. 15.The velocity of recession of a galaxy can be measured with Hubble’s law. 16.A quasar’s active region is roughly the size of the solar system. 17.White dwarf stars have no method of energy production – it is electron degeneracy pressure the keeps them from collapsing under their own gravitational force. 18. We live in an expanding universe. 19.Neutron stars are the compact, no longer fusion burning cores of stars, and are the result of a supernova. 20.Hubble’s Constant tells us the rate of the expansion of the universe. 21.The mass of a star as it enters the final stages of it’s life cycle determines what object will be generated. 22.A universe having less than critical density is considered unbound. 23.Collisions between galaxies heat and eject intracluster matter, which can form into new galaxies. 24.Cosmological redshift is the shift of the wavelength of received light from distant objects to be longer than the emitted wavelength, thus indicating motion away from us. 25.An object at 300K emits blackbody radiation at the wavelength of 9.6 nm, 6 and at 10 K, at .0029 nm 26.Galaxies are not distributed evenly throughout space, they form clusters and superclusters 27.The Milky Way region of the sky is our galaxy, the Milky Way. It has a higher concentration of stars than other regions due to conservation of angular momentum. Which is to say, many galaxies (including ours) have a disk shape due to the tendency of stars and matter to align to roughly the same plane, creating the disk arrangement that we can see spanning the night sky. 28.The large fraction of dark matter in the universe would have an effect on the end result of the galaxy, if it provides sufficient density of matter to cause universal collapse. 29.Evidence that the Sun is gaseous comes limb darkening and differential rotation. 30.If all the absorption lines of a star have been shifted slightly blue, then it would indicate the star is moving toward us. 31.v r H *OD thus D = v / Hr O Which is D = (1500 km/s) / ([75 km/s]/Mpc) which equals 20 Mpc 32.An active galactic nucleus (AGN) is a region within the centre of a galaxy that has an abnormally high luminosity across the EM spectrum. Examples of active galactic nuclei include >Quasars >Radio Galaxies >BL Lacerta Objects >Seyfert Galaxies 33.A pulsar is a pulsing radio source that is centered on the collapsed core of a high mass star. All spin rapidly, with beams of particles fired from the magnetic axes. 34.If a cloud of hydrogen atoms is moving away from us at 20% the speed of light, it would be expected for the H-alpha line (lambda = 656nm) to be lengthened due to redshifting. 35.Main sequence G-stars have surface temperatures that range from 5250K- 5950K 36.Cosmology is the science of the origin and development of the universe. 37.Measurements of a star’s color can tell us it’s mass and temperature. 38.A black hole is not supported by anything – it is gravitational force run to its extreme conclusion. A black hole is a point in space with no volume and infinite density. 39.A universe having more than critical density is BOUND. 40.The carbon atoms, nitrogren atoms, oxygen and calcium atoms all around us were formed in stars. 41.The Cosmic Background Radiation is thermal radiation left over from the big bang. It is essentially the oldest light in the universe. It is strong evidence against the Steady State model. 42.The Sun is not fusing helium as that will not occur until the core temperature reaches a much higher temperature than it is at current. 43.The stars in an elliptical galaxy are similar to the stars contained within the halo and the bulge: red, old, long-lived stars. 44.Most of the helium in the universe was made during the Big Bang. 45.A planetary nebula is a nebula consisting of ionized gas that has been ejected from old red giant stars late in their life. 46.Life may be most likely around stars of similar mass to the Sun. Stars too large live too short of lives to allow for sufficient time for life to emerge, and stars too small are more likely to tidally lock planets and sterilize them with flare activity. Thus, a star should be smaller than A (OBAFGKM) and yet larger than K. F and G are the most likely. 47.Stellar luminosity comes from its size and temperature. 48.The cosmological principle is that the distribution of matter in the universe is homogeneous and isotropic when viewed on a large enough scale, since forces should act uniformly throughout the universe. 49.Isotropy is uniformity in all orientations – i.e., that there is no preffered direction within the universe. 50.Homogeneity is having the same properties at every point – i.e., that the universe is the same everywhere. 51.Hubble’s Law is that the recessional velocity of a galaxy is proportional to its distance from us. v r H *OD Implication being that the universe is constantly expanding.
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'