the sun….center of the solar system. if little asteroids hit the earth all the time, big ones will...
TRANSCRIPT
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The Sun….center of the solar system
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If little asteroids hit the Earth all the time, big ones will hit us once in a while
Big Impact Home Page
Note Ries and Steinheim in Germany…Double impact
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Some impact craters of particular interest
• Chicxulub (possibly caused extinction of dinosaurs
• Manson (here in the Hawkeye State; 74 million years ago, similar in size to Chicxulub)
• Barringer Crater (Arizona; one of the best-preserved on Earth)
• Ries and Steinholm (Germany; same age, probably binary asteroid)
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At this point in the semester, we have discussed all the major classes of objects in orbit around the Sun, but not the Sun itself
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Let’s see how the Sun “stacks up” against some of the objects we have talked about
Object Radius (km) Mass (kg)
Earth 6378 5.97E24
Moon 1738 7.35E22
Mars 3394 6.39E23
Jupiter 71490 1.90E27
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Let’s think through how we determine some of the basic properties of the Sun
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How far away is the Sun?
By this time in the semester, you had better know!
A threat!
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How could we figure out the radius/diameter of the Sun?
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How could we figure out the radius/diameter of the Sun?
Answer: 696,000 km
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How could we determine the mass of the Sun?
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How could we determine the mass of the Sun?
Answer: 1.989E30 kg
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What is the Sun made of?
The stuff of the universe
The recipe of Jupiter and Saturn (or vice versa)
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Let’s see how the Sun “stacks up” against some of the objects we have talked about
Object Radius (km) Mass (kg)
Earth 6378 5.97E24
Moon 1738 7.35E22
Mars 3394 6.39E23
Jupiter 71490 1.90E27
Sun 696,000 1.99E30
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The Sun is in an entirely different class of objects than the planets…it is a star
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Question for SGU graduates (or anybody else): what kind of star is the Sun?
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One emphasizes (somewhat) different aspects of the Sun in a solar system
astronomy class
Reign of Akhenaten and Nefertiti (~1350 BCE)
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Point to make: when observed in the light of ultraviolet lines, the Sun is not a
constant, static object
SOHO watches the ultraviolet Sun rotate
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Why does the Sun shine?
Luminosity (or power output) of 3.85E26 Watts
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Because the Sun is the type of star it is…
• It produces the “right luminosity” for us (3.85E26 Watts)
• This luminosity is believed to have been stable for the last several billion years
• It shines at this luminosity long enough for us to arrive on the scene and enjoy it