Transcript The Sun to the Earth - Stanford Solar Center

Our Sun is a turbulent, active star
that can have
dramatic
effects on the
Earth and
other planets
Why Study the Sun?
SOHO
• Understand how the Sun affects the Earth and the solar system
• Understand how stars work
• Understand more about the laws of nature
SDO
The Sun is the only star known to grow vegetables.
(Dr.Philip Scherrer, Stanford University)
As the Sun turns
Like the Earth, the Sun rotates. However, unlike the Earth,
the Sun has a complex rotation mechanism.
What makes the Sun hot?
Fusion in the Sun’s core produces heat/energy
The Sun’s Roiling Surface
Size of Earth, for
comparison
Like fudge or oatmeal cooking, the
Sun’s surface boils up with heat,
then crashes down
Sunspots
Sunspots denote
regions of strong
magnetic fields. They
appear dark because
they are relatively cooler
than the surface.
How do magnetic fields
cause solar activity?
Most sunspots and
events on the Sun
are caused by
eruptions and tangles
of complex magnetic
fields
Seeing Magnetic Field
Lines
Plasma emission
traces out magnetic
fields in the solar
corona
The 11 year
sunspot cycle
The amount of
magnetic activity
on the Sun varies
in an 11 year cycle.
A regular cycle of sunspot numbers
over the past 300 years.
Dramatic changes occur
during the solar cycle
X-ray and magnetic activity
compared
Solar Eruptions
Common during the
Sun’s active periods
Huge flare of 28 October 2003
Solar prominence dwarfs Earth
in size
Explosions on the Sun
(Coronal Mass Ejections)
A billion tons of hot gas
being launched from the
Sun.
White circle in image indicates size and location of Sun,
which is blocked by a metal disk in the instrument.
A solar “wind” streams into
the solar system and shapes
Earth’s magnetosphere
The Sun generates
Space Weather in our
solar system
Solar activity can have a dramatic impact on
communications, satellites, and astronauts.
Solar activity causes
colorful aurorae
Space Weather
affects the Moon
and other planets
we hope to explore.
Mars
Aurorae
on
Neptune,
Saturn,
and
Jupiter
What color is the Sun?
1
The Sun appears white
to us
but it
radiates in all
wavelengths
(visible and
nonvisible
“colors”)
The electromagnetic spectrum
White Light Contains “Hidden”
Information
Hidden in light is information about
its source’s temperature, makeup,
even speed and distance
We are going to learn how to “read” this information