Classroom Presentation about the Sun

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Solar Plages and Filaments

Slide 39

Solar Flare, Prominence and Filament

Slide 40

Coronal activity increases with the number of sunspots.

Slide 41

SOLAR-TERRESTRIAL RELATIONSHIPS AURORAE

SOLAR WIND

MAGNETIC STORMS

RADIO FADEOUTS

COSMIC RAYS

WEATHER (?)

Slide 42

What makes the Sun shine?

Slide 43

vBut where does the Energy come from? c2 is a very large number!

v A little mass equals a LOT of energy.

Slide 44

Slide 45

ØNuclear fusion requires temperatures of at least 107 K – why?

Ø Atomic nuclei are positively charged ® they repel via the electromagnetic force.

Ø Merging nuclei (protons in Hydrogen) require high speeds.

v (Higher temperature – faster motion)

v At very close range, the strong nuclear force takes over, binding protons and neutrons together (FUSION).

v Neutrinos are one byproduct.

Slide 46

The energy output from the core of the sun is in the form of gammy rays. These are transformed into visible and IR light by the time they reach the surface (after interactions with particles in the Sun).

Neutrinos are almost non-interacting with matter… So they stream out freely.

Slide 47

Detecting Solar Neutrinos – these light detectors measure photons emitted by rare chlorine-neutrino reactions in the fluid.

Solar Neutrino Problem: There are fewer observed neutrinos than theory predicts (!)

A discrepancy between theory and experiments could mean we have the Sun’s core temperature wrong.

But probably means we have more to learn about neutrinos! (Neutrinos might “oscillate” into something else, a little like radioactive decays…)