Transcript Light and dark in this magnetic scan of the Sun indicate

Our star, the Sun is a big ball of gas
And it's 99 percent of our solar system's mass
It's an average star in our Milky Way
Warming the Earth every day
Galileo discovered sunspots
What are those things, those funny dots?
They're cooler parts, scientists feel
Caused by a stronger magnetic field
What powers our Sun and makes it so bright?
Those spots move around the face of the Sun
NASA/MSFC/NSSTC
Closest
Starto all... solar rotation!
Come on and tell me, what makes all thatThe
light?
Proving
Mitzi
Adams
Hans Bethe long ago reached the conclusion
A strange kind of movement, to do a full roll
The
Sun:
It changes Hydrogen to Helium by nuclear fusion
25 days in the middle, 36 at the poles
When fusion takes place light is created
And it makes its way out (although rather belated)
Through the Photosphere that's the part that we see
The light comes out and shines on you and me
What about flares? I've heard of them here
They're like giant explosions in the Chromosphere
The magnetic fields above those sunspots
Reconnecting again after being in knots
About a million Earths could fit in the Sun
But if you were there you wouldn't have much fun
It's six thousand degrees at the photosphere
And much hotter inside the solar atmosphere
Above the Chromosphere the Corona is placed
It's millions of degrees and reaches way into space
It's very thin, but read my lips
That's the part that you see in a solar eclipse
There are a few places where it's not so hot
Like at the center of a big sunspot
But heat is relative it's still pretty warm
Sitting on a sunspot would do you great harm
That's the end of our song about Mr. Sun
We hope that you find that learning is fun
But never look at the Sun, you could go blind
Just keep on enjoying that warm sunshine!
The Sun
• The Sun is located in a spiral arm of our
Galaxy, in the so-called Orionis arm, some
30,000 light-years from the center.
• The Sun orbits the center of the Milky Way
in about 225 million years. Thus, the solar
system has a velocity of 230 km/s (or
830,000 km/hr...or...515,000 mi/hr)
• Our galaxy consists of about 100 billion
other stars and there are about 100 billion
other galaxies
• The Sun has inspired mythology in many
cultures including the ancient Egyptians,
the Aztecs, the Native Americans, and the
Chinese.
• The Sun is 333,400 times more massive
than the Earth and contains 99.86% of the
mass if the entire solar system
• It consist of 78% Hydrogen, 20% Helium
and 2% of other elements
• Total energy radiated: 100 billion tons of
TNT per second
A Few Major Events in Solar Astronomy
1610
Galileo Galilei and
Thomas Harriott
observe sunspots with
a telescope
1908
George Ellery Hale
discovers magnetic fields
on the Sun
1949
Solar X rays discovered
from rocket flight
1962
OSO 1 launched -- OSO 8
ceased operations in 1978
1973-74
Skylab -- produced 35,000 images in 9 mos.
1949 X rays from the Sun discovered
Herbert Friedman 1916-2000
flew a geiger counter on a sounding rocket during a solar flare,
demonstrated that emission was principally of x ray photons
a series of Nike-Asp rockets fired during the 1958 total solar
eclipse demonstrated that the x-ray emission extended far
beyond the visible disk of the sun and was concentrated in
small regions on the surface
These series of rocket observations also demonstrated the
effect of solar x-rays on the upper atmosphere.
During this period of time he also obtained the first image
of the sun with a pinhole camera, flew a spectrometer for
measuring hard x-rays, and developed and flew the first satellite dedicated to solar observations,
SOLRAD, that traced out the solar x-ray flux during a solar cycle.
Skylab
May 14, 1973 - July 11, 1979
4 major instruments, 2 X-ray telescopes
Xray Images of Coronal Holes
Magnetic Structure of Corona
Seen Even in Quiet Areas
Observations of Coronal Mass Ejections
•
•
•
The Sun’s Structure
Core
– Where the energy is created.
– Every second, nuclear reactions
convert about 700 million tons
of hydrogen into helium.
Radiation Zone
– Where energy is carried by
radiation.
Convection Zone
– Energy transported by
convection (just like boiling
soup) where heat is transported
to the photosphere.
Sunspots
Darker areas (umbra, penumbra)
Strong magnetic fields
Inhibit energy transport from
solar interior
These areas cooler, therefore
darker
Light and dark in this magnetic
scan of the Sun indicate
concentrated areas of intense
magnetic field.
Frequency varies with an 11-year
solar cycle
Solar Cycle
Maunder minimum
The Solar Dynamo
the Sun's magnetic field is generated by a dynamo within the Sun
the Sun's magnetic field changes dramatically over just a few years
the magnetic field continues to be generated within the Sun,
it’s produced in interface layer between radiative and convective zone
Flares and Things
Physical Characteristics of Flares
How are Flares Classified?
Flares are classified according to the order of magnitude of the peak burst intensity (I)
measured at the Earth in the 0.1 to 0.8 nm wavelength band as follows:
Class
B
C
M
X
Flux
Ergs/cm2/s
I < 10-3
10-3  I < 10-2
10-2  I < 10-1
I  10-1
A multiplier is used to indicate the level within each class. For example,
M6 = 6 x 10-5 Watts/m2
The Biggest Flare on Record
 At 21:51 UT, Monday 2 April 2001, active region
9393 unleashed a major solar flare reclassified as
at least an X20 It appears to be the biggest flare
on record, most likely bigger than the one on 16
August 1989 and definitely more powerful that
the famous 6 March 1989 flare which was related
to the disruption of the power grids in Canada.