and the Sun
What is it?
Why should we care?
Elementary level presentation
The Sun rises each morning to give us
warmth and light . . .
and sets each night,
Credit: Mila Zinkova
but out in space, it shines
all of the time.
Day and Night
At any time of day, about half the Earth
has daylight and half has night as the
Earth turns.
From Earth to the Sun
Play: Earth_to_Sun.mov
Soar from the White House in Washington, D.C. into space, past the moon,
and beyond. See the planet Mercury eclipse the Sun, then fly through solar
magnetic loops on the Sun’s surface and dive into a sunspot.
The Sun right now!
http://soho.nascom.nasa.gov/data/realtime/eit_304/512/
If you have an internet connection, you can copy
and paste this link into a browser to see what the
Sun looks today (in ultraviolet light) as observed
by the Solar and Heliospheric Observatory in
space. If not, just continue on to the next page.
Direct solar viewing
Filtered telescopes
Students can see the Sun too!
Sunspotters show sunspots
Safety Note: Do not look directly at
the Sun without the right equipment.
Special solar viewing glasses!
Our Solar System
The Sun is at the center of
our solar system. All the
planets in the solar system
move around it.
Sun as a Star
• The Sun is a
star, just a lot
closer to Earth
than any other
stars
• There are
billions and
billions of stars,
more than
grains of sand
on Earth
Groups of stars at night in our Milky Way galaxy
Learning about stars
• The next closest star,
Alpha Centauri, is
very, very far away
• Studies suggest that
almost all stars work
basically the same way
• By learning more
about our star, we learn
about all stars
Where the inside action is
• The Sun is a ball
of hot gases
• Heat and light
come from the
center of the Sun,
its core
(Water boils on a stove at
100 degrees C.
(212 degrees F.)
5,000 degrees C.
(9,000 degrees F.)
15 million degrees C.
(27 million degrees F.)
How big is it?
The black dot
represents the
approximate size
of Earth
One million Earths
could fit inside the Sun
The Sun is 108 Earths across
Speaking of size. . . planets
Let’s take a closer look
• The Sun’s surface
looks like boiling
oatmeal or soup,
always churning
• Each “cell” shown
here is about
Texas-sized
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PNG decompressor
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Play: Churning.mov
The Sun is also the source of radiation and storms that we call
SPACE WEATHER!
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PNG decompressor
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This real clip will show storms blasting from the Sun. We see both the Sun
and its atmosphere as it blasts energetic particles out into space. The solar
storms are the many lighter clouds that you see here.
Play: Bursts.mov
Credit: SOHO/ the SolarMax IMAX film
The changing Sun
The Sun, like all
stars, is a busy star.
It is always active,
always changing.
(Shown here in ultraviolet
light. Brighter areas are
more active.)
Play: RedSun.mov
QuickTime™ and a
PNG decompressor
are needed to see this picture.
Sunspots
Play:
Spot_closeup.mov
Close-up
of sunspot
Sunspot Cycle
• The Sun
changes over
an 11-year
period
• The number of
spots on it is a
way to measure
how active it is
2008 - the Sun is
much less active and
has almost no spots
2001 - the Sun
is very active!
Solar spinning
• Like Earth, the Sun turns too!
• The Sun spins (rotates) every 27 days or so.
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PNG decompressor
are needed to see this picture.
Play: Spinning.mov
This turning
would be hard
to see without
sunspots!
Action near the Sun’s surface
•
•
•
Magnetic forces control
the particle movement
above the Sun’s surface
Most of this involves an
active region (usually
seen as a dark sunspot
in visible light)
All this motion shows
how active the Sun
really is
(Video clip covers about two days)
Play: Sun_edge.mov
Some magnetic loops
Circular loops rise up from the Sun above sunspots -- they are
powered by magnetic forces and show magnetic field lines
Play: Loops.mov
Video credit: SolarMax IMAX film
Storms at their source
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When magnetic forces above sunspots erupt, violent storms can burst from the Sun.
This is the main source of space weather. The white specks near the end of the
video are particles from the blast hitting a NASA spacecraft’s camera.
(The green color is just color added.)
Play: Source.mov
What are Coronal Mass Ejections
(CMEs)?
• These are solar
storms: clouds of
particles that explode
from the Sun
• CMEs send billions
of kilograms of matter
at 1 to 3 millions of
kilometers an hour
into space
• Sometimes they head
towards Earth
Play: CMEstorm.mov
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PNG decompressor
are needed to see this picture.
Stormy
weather
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In 2003 the Sun blasted out many strong storms over a one week
period. (Green color is added.) The largest storms are coronal
mass ejections. The few, small bright flashes are solar flares.
Play: Oct_storms.mov
A solar storm in slow motion
QuickTime™ and a
None decompressor
are needed to see this picture.
With the Sun blocked (red disk) we can see a CME bursting a
cloud of particles into space. The white circle shows the size of
the Sun. These may occur every few days or not for weeks.
Play: Slo_mo.mov
Storm clouds heading into space
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Again, with the Sun blocked out, we see in the video clip many
clouds of particles blasted out into space over four days. If one is
headed towards Earth, then we may have some “space weather.”
Play: Blue_storms.mov
Earth’s magnetic shield
Earth is like a big magnet with north and south poles with a large
magnetic field around it.
Our magnetic shield
(shown in blue)
protects us from
charged particles from
the Sun. These particle
clouds take about 2-3
days to get to Earth.
Spacecraft track their
progress.
Play: Magneto.mov
QuickTime™ and a
PNG decompressor
are needed to see this picture.
A solar storm heads our way
When a solar storm hits Earth, our magnetic shield protects us.
Some particles flow down to our North and South Poles and
create glowing lights called aurora. They pose no health dangers.
Aurora ovals
Aurora when seen from space are oval in shape
and occur most often near the Poles. Here it is
shown on a drawing of Earth.
Play: Aurora.mov
Aurora from space
When storms from the Sun excite
elements in Earth’s atmosphere, the
elements glow in different colors.
Aurora occur
around 40 miles
(70 Km) above
Earth.
(Taken by astronauts)
Aurora on Earth
Video credit: Aurora Experience
Aurora, often called the Northern and Southern Lights, are
visible signs of solar storms.
Play: Aurora.mov
How do solar storms affect us?
Spacecraft
failures
Power system damage
Astronaut safety
Radio problems
Navigational problems
Bursts of energy from solar storms can upset electronic equipment
Astronaut safety
Astronauts in space can get sick from radiation from solar
storms. For them to travel to the Moon and Mars, better
protection and warnings will be needed.
Play: Spacewalk.mov
Global Warming
Is the Sun causing the Earth to get warmer? That is one topic that
scientists who study the Sun and Earth are trying to figure out.
Studies seem to show that man-made causes are mostly to
blame. Changes in the Sun may cause a little warming.
Solar exploration in space
NASA studies the Sun
and space weather from
space:
• SOHO (the Solar and
Heliospheric
Observatory) has been the
main solar watchdog since
1996 (shown in video).
• TRACE is learning
more about solar storms
too. And there are others.
Play: SOHOfly.mov
STEREO mission
This recent solar mission launched in Oct. 2006. Two NASA
spacecraft study the Sun from ahead of and behind Earth. We
got 3-D views of solar storms for the first time and more
detailed images than ever before.
(The video clip shows detailed
close-ups of magnetic loops above
the Sun from STEREO)
Play:
Arc_loops.mov
Solar Dynamics Observatory (SDO)
• Launch planned for late 2008 or early 2009
• A newer, improved spacecraft
• Will give us more detailed images and more often
Watching the Sun
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Solar activity is being watched and studied all the time by
NASA. If there is a possible solar storm heading our way,
then alerts are sent out.
NASA will continue to explore the Sun-Earth
connection. The more we depend on technology, the
more we need to understand space weather and how it
can affect our lives.
Play: Finale.mov
Video clip: SolarMax, Chicago Museum of Science & Industry
THE
END