Studying the Sun

HOMEWORK: REVIEW (1-7,9-12,14-17) Page 414: REVIEW (1-7,9-12,14-17) using complete sentences 15 Questions using complete sentences and PROBLEMS (2,4,& 5) Page 415 PROBLEMS (2,4,& 5) SHOW WORK for credit SHOW WORK for credit. 70 points possible Due Tuesday 15 March, 2016 Due Tuesday 15 March, 2016 at the BEGINNING of class – Tardy will be worth ½ credit.

I. First people to observe SUNSPOTS were the CHINESE early CHINESE over 1500 years ago…. without a telescope!

Galileo Galilei Galileo Galilei – First person to observe that sunspots moved in a regular pattern, concluding that the Sun __ __ __ __ __ __ __.Sun R O T A T E S

1859 the spectra of the Sun determined it’s chemical make-up. Helium discovered!

Solar Telescope Solar Telescope – Projects a large image of the sun into a dark underground room (or small ones project the image on a board.

Telescope at Kitt Peak National Observatory. The McMath-Pierce Solar Telescope at Kitt Peak National Observatory.

SOLAR PHYSICISTS Astronomers who study the Sun

Skylab ions Sun Skylab missions photographed the Sun Satellites are used to study the Sun to study the Sun without interference from our without interference from our Atmosphere! Atmosphere! many satellites were used to view the Sun many satellites were used to view the Sun.

ULYSSES Sun’s POLES 1990 – ULYSSES was launched to view the Sun’s POLES, which were not observed prior to then.

SOHO ( Solar & Heliospheric Observatory) An international collaboration between ESA (European Space Agency) and NASA to study the Sun from its core to the outer corona and the solar wind, launched in 1995.

II. PROPERTIES (FACTS) of the Sun.  110 Earths wide!  OOOOver one million (1,000,000) Earths could fit into the Sun if it is hollow!  MASS = 745 times more than ALL planets combined!

 Surface (photosphere) (photosphere) temperature 5,500- temperature 5,500- 6,000 o C 6,000 o C  Interior temperature (core) thought to be (core) thought to be as high as 15,000,000 o C as high as 15,000,000 o C

III. Sun’s Three Atmospheric Regions A.PHOTOSPHERE – Bright YELLOW “surface” (the part we see) of the Sun. ~400 Km thick YELLOW “surface” (the part we see) of the Sun. ~400 Km thick

Photosphere of the Sun made up of millions of “cells” called granules. Each granule is roughly 1,500 Km across (almost as wide as our Moon!) Granules are due to falling, cooler gases on the photosphere.

The Sun’s atmosphere layer which can be observed with UV and X-ray telescopes, lies above the photosphere is called the Chromosphere. Seen during an eclipse. RED due to glowing Hydrogen! (and cooler than photosphere.)

Corona [crown] – Very thin outer layer extending >1,000,000 Km away from Sun. Seen only during solar eclipse as a faint, pearly glow. 1-3 Million Kelvin hot!

CONVECTION ZONE : Beneath photosphere bringing hotter waves of gases up from the core Beneath photosphere bringing hotter waves of gases up from the core.

Nuclear Fusion in the core converts 4 H protons into Helium, neutrinos, positrons and Energy.

7 main zones to know:

Solar Neutrinos from the Sun’s core pass through the Earth and can only be detected by their affect on underground detectors.

Most Solar neutrino experiments are located deep underground to shield them from cosmic rays that could mimic a neutrino signal in the detector and interfere with the measurement. In certain classes of neutrino detectors, the interaction of the neutrino with a transparent detector medium creates light that can be detected by photodetectors. In radiochemical experiments, one identifies and counts individual atoms which have undergone a nuclear reaction with the neutrino.

Solar PROMINENCES Flame-like arches extending from the photosphere into the corona. May last several hours! May extend millions of Km above photosphere!

A huge prominence blasted away from the sun April 19 th, The massive tendril of plasma was nearly a quarter the diameter of the sun itself when the Solar and Heliospheric Observatory (SOHO) snapped this picture.

SUNSPOTS – Dark spots on the photosphere. Many are larger than Earth! DARK because they are cooler than photosphere. But still very hot, around 3,000-4,500 K

UMBRA Dark center of Sunspot is called the UMBRA. PENUMBRA Lighter rim is called the PENUMBRA

Sunspots appear in North- South magnetic pairs.

Sun rotation is NOT same all over since it is a gas! Equator - 25 days rotation Poles rotate slower at 27 days to completely encircle it, like Jupiter.

Sunspots vary from none appearing for many days, 11 year cycle to over 100 at a time over an 11 year cycle.

Solar Winds: - Constant stream of - Constant stream of electrically charged electrically charged particles from the particles from the Corona. Corona.

AURORA - Caused by solar winds penetrating Earth’s magnetic field at the poles and “lighting” up ions in the ionosphere.

Aurora Borealis The “Northern Lights”

Aurora Australis The “Southern Lights” over the Australian side of the Earth.

A CORONAL HOLE (Coronal Mass Ejection –CME) streaming solar wind. Coronal Holes are caused by “huge gusts of solar wind.”

Solar Flares Outbursts of light associated with sunspots. also send off solar winds.

MAGNETIC STORMS occur when Solar wind plasma from coronal holes and solar flares add an extra “Punch” to the normal solar winds, causing electrical power surges, making extra big Aurora’s and interfering with radio wave transmissions on Earth.

Magnetic Storms from coronal holes &/or solar flares.

Now read the chapter, practice the homework and labs and prepare for the test.