Our Dynamic Sun

You should never look directly at the sun.

The Sun is Large

• How

• Large

• is

• It?

http://space-facts.com/how-big-is-the-sun-million-earths/

• 1.3 million Earths will fit in the sun.

• https://www.youtube.com/watch?v=qLB5ma2Yz1I

• What is happening up there?

Interior

• Interior: http://solarscience.msfc.nasa.gov/interior.shtml

• 1. Core: The Sun's core • is the central region • where nuclear reactions• consume hydrogen to • form helium.• Temp: 27,000,000 OF

Here is how fusion works:

• (3) step process called proton-protonchain. (fusion)

step one summary

• Proton + Proton

• H + H = deuterium + neutrino

• and a positron

Gamma Ray

• When a positron collides with its • antiparticle (electron) they annihilate• to form a gamma ray.

• These gamma rays eventually make their way into space in the form of sunlight.

• neutrinos just come out and can eventually• make it to earth.

Step Two summary:

deuterium + proton = Helium-3 nucleusand a gamma ray.

Step Three Summary

Two Helium-3collide to forma Helium 4 nucleus and2 extra protons

Radiative ZoneCharacterized by the factthat the energy from the core is carried by photonsthrough the radiative zone.

Because of the density, it takes a photon about a million years to finally reachthe interface layer.

Radiative Zone

• Temperature falls to about 2,000,000 0C progressively through this zone.

Tachocline (Interface Layer)

• This is an area that lies between the Radiative zone and the Convective Zone.

• This is where the suns magnetic field is generated.

• Thin layer with border behaviors to match each border.

• This change in fluid flow velocities gives its alternative name: Tachocline Layer.

Convection Zone

• Outer most layer. This is the begining

• of the visible surface.

• Material is more opaque here because

• heavier ions hold onto some of their

• electrons.

• Radiation has a harder time getting through.

Convection Zone

• So heat is trapped and the fluids start to boil. Then material starts to move

• higher and since this material is warmer

• it will rise higher until it reaches the surface.

At the visible surface the temp is about

• 5426 0C. Density is .0000002 g/cm3 .

• Convective motion is visible at the surface.

Interior Summary

Photosphere

• Photosphere: The • visible surface of the• sun that we are most• familiar with.

• Has sunspots, prominences, • and granules.

• http://solarscience.msfc.nasa.gov/surface.shtml

Chromosphere

• http://solarscience.msfc.nasa.gov/chromos.shtml

An irregular layer above the photospherewhere the temperature rises from 6000°C to about 20,000°C.

At these temps Hydrogen emits red light which is seen as prominences during a solar eclipse.

Transition Region

• The Transition Region: http://solarscience.msfc.nasa.gov/t_region.shtml

The transition region is a thin and very irregular layer of the Sun's atmosphere that separates the hot corona from the much cooler chromosphere.

The Transition Region

Instead of hydrogen, the light emitted by the transition region is dominated by such ions as C IV, O IV, and Si IV (carbon, oxygen, and silicon each with three electrons stripped off)

Corona

• 1. Sun’s Outer Atmosphere

• Features: Streamers, Plumes, Loops

White Light Corona – visible during eclipse.

Corona

Emission line Corona: Hydrogen and Helium

are super heated to temps > 1,800,000°F. They are stripped of their electrons. Other elements like N, C, and O are stripped down to nuclei. These ionizedelements produce odd emission lines in a spectrum.

Corona

X Ray Corona: The corona shines brightly in x-rays because of its high temperature. On the other hand, the "cool" solar photosphere emits very few x-rays.

Space Weather

• The solar wind streams off of the Sun in all directions at speeds of about 400 km/s (about

• 1 million miles per hour). • The source of the • solar wind is the • Sun's hot corona. • The temperature of• the corona is so high • that the Sun's gravity • cannot hold on to it.

Coronal Mass Ejections

• CMEs: http://www.space.com/12581-stunning-photos-solar-storms-flares-sun-weather.html

• Coronal Mass Ejections: are huge bubbles of gas threaded with magnetic field lines that are ejected from the Sun over the course of several hours

• These can cause interference with • electronics.

More Space Weather

• Solar Wind: http://solarscience.msfc.nasa.gov/SolarWind.shtml

• Heliosphere: http://solarscience.msfc.nasa.gov/Heliosphere.shtml

Heliosphere

• The heliosphere is a bubble in space produced by the solar wind.

Some Interesting features

• http://www.nasa.gov/mission_pages/sdo/news/first-light.html

• The above is for SD Observatory facts from NASA and a solar prominence video.

• Solar Flare:• http://www.nasa.gov/mission_pages/sunear

th/multimedia/Solar-Events.html#.VMp13i4sCDk

Montage

More Montage

And even more Montage