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# minitest2 - Arcturus is at a distance oF 11.3 parsecs From...

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ASTRONOMY 294Z: The History of the Universe Professor Barbara Ryden PRACTICE MINI-EXAM Short Answer Problems 1) Who lived frst: Kepler or Copernicus? 2) IF the density oF the universe were greater than the critical density, would the universe be positively curved, negatively curved, or ±at? 3) Which is more massive, an electron or a neutrino? 4) A newly Formed zircon crystal contains 1000 uranium-238 atoms. How many uranium-238 atoms will be leFt aFter two halF-lives? 5) A galaxy has a radial velocity oF 14,000 kilometers per second. Using Hubble’s Law, what is its distance From us? 6) Arrange the Following objects in order oF increasing mass: Jupiter, Sun, brown dwarF, Earth. 7) Which has the longer wavelength, visible light or X-rays? 8) IF a star is at a distance oF 2 parsecs, what is its parallax angle, in arcsec- onds?

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Mathematical Problems 9) The stars Arcturus and Vega have the same fux as seen From the Earth.
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Unformatted text preview: Arcturus is at a distance oF 11.3 parsecs From the Earth; Vega is at a dis-tance oF 7.76 parsecs From the Earth. What is the ratio oF the luminosity oF Arcturus to the luminosity oF Vega? 10) The star Proxima Centauri has a mass 0 . 12 M sun , where M sun is the Sun’s mass. Also, Proxima Centauri has a luminosity 0 . 00014 L sun , where L sun is the Sun’s luminosity. IF the Sun’s liFespan is t sun = 10 billion years, what is the liFespan oF Proxima Centauri? Essay Question 11) Our crotchety old pal “±lat Earth ±red” reFuses to believe that exoplanets (planets around stars other than the Sun) exist, since astronomers haven’t been able to take pictures oF them. Write an explanation, in simple terms that a non-spet like ±red can understand, oF either the radial velocity method or the transit method For ²nding planets....
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## This note was uploaded on 07/17/2008 for the course ASTRO 294 taught by Professor Ryden during the Winter '08 term at Ohio State.

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minitest2 - Arcturus is at a distance oF 11.3 parsecs From...

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