C a parsec is too big of a unit to use within our

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c) A parsec is too big of a unit to use within our solar system, which is only around 1/2600th of a parsec across (c.i.1.a) Typically you would describe the distance between nearby stars in parsecs, kiloparsecs for the distance between parts of a galaxy or within galaxy groups, and megaparsecs for distances between galaxy clusters. 171) Parallax is the change of angular position of two observations of a single object relative to each other as seen by an observer, caused by the motion of the observer. a) This is the apparent shift of an object against the background that is caused when the observer changes positions. b) When standing in one place it looks one way; if the observer moves, the background changes and the object looks different. 172) Pulsars are highly magnetized rotating neutron stars which emit a beam of detectable electromagnetic radiation in the form of radio waves. a) The radiation can only be observed when the beam of emission is pointing towards the Earth. b) Most pulsars actually are detectable only by their radio radiation--they release too little visible light to be seen with the human eye. c) Because neutron stars are very dense objects, the rotation period and the interval between observed pulses are very regular. 173) A Quasar is an extremely bright and distant active galactic nucleus--the very bright center of a distant galaxy powered by a black hole in the galaxy in which it's located. a) Quasars were first identified as high redshift sources of electromagnetic energy including radio waves and visible light. b) They are considered the most distant objects discovered by astronomers, so far away that their light takes billions of years to reach the Earth. c) The study of quasars gives astronomers a glimpse into the early stages of the universe. d) They radiate enormous amounts of energy and are the most luminous objects ever detected, some being as much as a trillion times brighter than our sun. d.i)A quasar is a compact halo of matter surrounding the central super massive black hole of a young galaxy. 174) Redshift occurs when the frequency of a photon of light is shifted towards the red end of the electromagnetic spectrum. a) A shift towards the red end of the spectrum indicates lower energy, which means longer wavelength. b) One instance in which redshift is observed is when a light-emitting object (such as a distant galaxy) is moving further away. c) As it moves away, the wavelength of the light is stretched out, causing the light to shift towards red. d) On the other hand, if the source of the light were moving closer, blueshift would result as the wavelength of the light gets compressed (higher energy, higher frequency, lower wavelength) 175) Cosmological redshift is caused by the expansion of the universe.
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