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Daily Review #7. Why does the Sun stay about the same size? What is the difference about the fusion in a main sequence star, red giant and red supergiant? Describe the fate of a star the size of our Sun. What will probably happen to VY Canis Majoris a star 950 times the size of the Sun?
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Daily Review #7 • Why does the Sun stay about the same size? • What is the difference about the fusion in a main sequence star, red giant and red supergiant? • Describe the fate of a star the size of our Sun. • What will probably happen to VY CanisMajoris a star 950 times the size of the Sun? • VY CanisMajoris is 5,000 light-years from Earth, what does that mean?
Age of the Universe • Rocks on Earth • 4.2 billion years • Oldest stars • 10-12 billion years • Universe must be older • Estimate backwards • 13.8 billion years http://www.universeadventure.org/big_bang/conseq-ageofuniv.htm http://scienceblogs.com/startswithabang/2009/07/31/the-size-of-the-universe-a-har/
What happens next? • Big Crush • Stops expanding • Gravity causes to crush • Repeat the process • Big Chill • Expand at slowing rate • Get cooler as expands • Big Rip • Expand at increasing rate • Everything gets ripped apart http://sandeepdmisra.wordpress.com/2011/04/ http://ffden-2.phys.uaf.edu/212_fall2003.web.dir/eli_sonafrank/Expansion_-_Fate_of%23168EE9.html
What else is out there? • Visible matter • Dark matter • Does not give off light • Things weigh more than they should • Dark energy • Causing the increase in expansion rate seen in most recent data • Thus fate of the universe is… • Big Rip • Adding these items makes models better fit actual observations http://hubblesite.org/hubble_discoveries/dark_energy/de-what_is_dark_energy.php
Daily Review #8 • How old is the universe estimated to be? • Describe the three hypotheses about the fate of the universe. • How is dark matter and dark energy different from all other matter and energy? • Of the items we have talked about in class, what do you think we should research further and why?
Light-Years • Distances in space are very large • Created new unit - Light year • Distance • 9.5×1012 km or 5.9×1012 mi • Proxima Centauri : 2.5 x 1013 miles