The_Sun - The Sun Basic Solar Data 100 times larger than...

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Unformatted text preview: The Sun Basic Solar Data 100 times larger than the Earth One million times as massive as Earth Surface Temperature ~10,500 F (5,800 K) 10 500 (5 800 Rotates once per month Is half a degree in size on the sky Basic Solar Data Solar Atmosphere Photosphere p (“Light” region) Chromosphere (“Color” region) ( l i ) Corona ( Crown ) (“Crown”) Photosphere The photosphere is the “surface” that we see. It is not a physical boundary but an optical one. The absorption of light b h li h by the H- molecule produces the l l d h sharp edge. Height 400 km Temperature 5800 K (down to 4500 K) Surface is covered with granules. Photosphere Granulation Size of Texas + Oklahoma Centers are 50 – 100 K hotter than edges Persist for ~8 minutes Photosphere Convection Hot gas rising upward produces the bright granules. Cooler gas sinks downward along the boundaries between granules. This gas is about 50 K cooler, so it is slightly less bright. Granulation Movie Chromosphere The chromosphere is the region of color. Namely, helium, which has red emission lines, was first detected in hi i this region during solar eclipses. i d i l li Height 2000 km to 3000 km Temperature 4,500 K to 10,000 K Contains millions of spicules C i illi f i l Chromosphere Spicules p As much as 10,000 km high Temperature quickly rises to T t i kl i t 1,000,000 K Lasts for about 15 minutes About 300,000 spicules exist at any given time yg Transition Region PRS Question 1. The common structures in the chromosphere are a. Granules d. Winds b. Spicules e. Aurorae c. c Holes Corona The corona is the “crown” of the Sun. It is best seen during a total solar eclipse. Height H i ht millions of k illi f km Temperature millions of K Heated by magnetic fields. Best viewed in the X-ray. Can be a very violent region. g Images of the Corona Solar Wind Stream of charged particles, mainly S f h d i l i l protons. The solar wind exists because the gases in the corona are too hot to be confined by solar gravity. The speed of the solar wind near the Earth’s orbit averages about 400 km/s and its density is usually km/s, two to ten ions per cubic centimeter. But both are highly variable. The solar wind’s interaction with the Earth’s atmosphere creates aurora. PRS Question 2. The temperature of the corona of the Sun a. is about the same as the photosphere, 5800 K b. is about twice as hot as the photosphere, 12000 K c. c is very cold, because it merges with cold interstellar space cold d. is very hot, about one million degrees e. is very cool, because it is far from the Sun’s interior Phases and Eclipses Eclipses Lunar Solar Inclination of Moon s Orbit Moon’s Conditions for Eclipses Eclipse Side View Diameter of the Earth = 12,746 km 5 inches Earth-Moon Distance = 384,400 km 12.5 feet Diameter of the Moon = 3,476 km 1.25 inches Earth’s Shadow (1o) 2.5 inches Moon’s Highest Offset (5o) 13 inches Geometry of Lunar Eclipses A Total Lunar Eclipse Science Learned Ancient Astronomers realized that the Earth was casting its g shadow and that the Earth had to be spherical. Why? Because the shadow’s edge was ALWAYS a curve. Today most of the science concerns the reddish color during tota ty totality because this tells us something about the Earth’s t s te s so et g t e at s atmosphere. Geometry of Solar Eclipses A Total Solar Eclipse An Annular Solar Eclipse Science Learned Total Eclipses allowed for the study of the Sun’s atmosphere. p y p This included the discovery of the Chromosphere and of Helium. A Total Soalr Eclipse was used to validate one of Einstein’s predictions of General Relativity; namely, that the path of light w will be be t when it travels near a massive object. bent w e t t ave s ea ass ve Upcoming Eclipses in 2012 May 20: y Jun 04: Nov 13: Nov 28: Annular Solar Eclipse p Partial Lunar Eclipse Total Solar Eclipse Penumbral Lunar Eclipse Not in US End of Partial seen Not in US Pathetic Eclipse Tracks ...
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This note was uploaded on 03/04/2012 for the course PHYS 2022 taught by Professor Jarrio during the Spring '12 term at Central GA Tech.

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