1 The Sun

2 Pictures taken from SOHO Solar and Heliospheric ObservatorySOHO

3 Facts about the Sun Composed of plasma (the 4th state of matter) –Plasma- ionized gas  electrically neutral atoms are split into positively charged fragments and free electrons. –Electrons are moving so fast they overcome the attraction to the positive nucleus. Age = 4.6 billion years old 10 billion years is its expected lifetime (H  He) Diameter  1.5 million km OR 109 Earths wide Mass  1.99 x kilograms or 300,000’s Earths * volume of the Sun is 1,299,400 times bigger than the volume of the Earth. You could fit OVER 1 million Earth’s in the Sun!

4 Sun Facts continued Rotation = –27 days at the equator –31 days near the poles Surface Temp = 5780 K or 10,400 0 F Core Temp = 16,000,000 K Most of its energy is released in the visible wavelengths (yellow)

5 The Sun is AVERAGE. –Average temp –Average mass –Even average color (yellow is right in the middle of ROYGBV) Large, HOT stars give off most of their light in the BLUE. Small, COOL stars are red. BLUE is HOT, red is not. Sun Most light given off by the Sun is Green/Yellow BIG, hot, blue star Small, cool, red star

6 Composition of the Sun CompositionSurfaceCoreTotal Hydrogen94%68%74% Helium5.9%32%25% Other0.1%0.0very small

7 Where does the energy come from? Fusion- Hydrogren fusing into helium mass lost is turned into energy. E=mc 2 Click HERE for fusion animation.HERE

8 Why doesn’t the Sun blow itself up? Gravity is always trying to pull matter together. The mass of the Sun is so great that it has a hard time stopping gravity. Hydrostatic equilibrium- the expansion of the super hot ionized gas (plasma) pushing out EQUALS the compression from gravity pulling in.

9 Differential rotation- the equator of the Sun rotates faster than the poles. Causes the magnetic field to become “warped” or tangled. Causes massive magnetic field problems

10 Solar Max and Solar Min It takes 11 years for the Sun’s magnetic field to become “warped” or “tangled” and right itself back to normal. When the mag field lines are “normal” or not tangled, we have Solar Minimum. Which means the Sun is less active. Less flares, Sunspots, Aurora’s. When it’s “warped” or tangled, we have Solar Maximum. More flares, sunspots, aurora’s. When the Sun “rights itself” or UNtangles the magnetic field lines, the Magnetic NORTH and SOUTH flip. South goes to the TOP, north= bottom

11 Warping the Sun’s magnetic field

12 Solar Max was in 2000/2001 Next 2012/2013 Last solar minimum 2008 Next 2019-ish

13 Sunspot Cycle

14 Surface Features of the Sun The Sun’s magnetic field causes ALL... -sunspots -Flares -prominences

15 Sunspots cooler regions resulting in dark blemishes on the Sun’s surface. 10,000 km across (about the diameter of E) Have an umbra (dark center) and a penumbra (less shaded surrounding) Temps in the umbra reach 4500 K. (cooler than surroundings). Appears dark, but it’s not. Magnetic field is 1000 times greater than surrounding surface.  This strong mag. field redirects convective hot gas. Usually associated with brighter areas called Plage- hotter areas of rising convection (possibly) 22 year cycle in magnetic field polarity (N/S flipping)

16 Sunspot BIGGER than the Earth ISS Sunspots

17 Sunspots are associated with… An increase in solar flares/prominence. An increase in the RELEASE of radiation. There is a shift in the global average temperatures as Sunspots change. –More Sunspots, higher ave temps

18 What is the difference between a solar flare and prominence? Basically they are the same thing. Flares an eruption on the Sun that shoots out from the surface of the Sun for thousands of kilometers. Prominence an eruption on the Sun shoots out for thousands of kilometers and back again forming LOOPS.

19 Solar Flare

20 Flare

21 Prominence

22 Filament When a flare or prominence shoots towards Earth.

23 Plage SunspotSunspot Filament

24 Problems from “Space Weather” The effects of solar storms on the ground can also be expensive. Surges in power lines and long uninterrupted oil and gas lines can occur. The extra current in the power lines can burn out transformers, leading to large-scale brown-outs or blackouts. Electricity in pipelines can enhance the rate of corrosion.

25 Problems from “Space Weather” Satellites are particularly vulnerable to electrical effects of Space Weather as they are NOT buffeted by the incoming gas and radiation. The charged particles and ionizing radiation causes our atmosphere to expand, which in turn, creates extra drag on our satellites. This causes a loss of altitude. Too many charged particles can cause electrical components to burn out.

26 At home, watch the following: Aurora’s Sunspots

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