Download what causes an aurora?

WHAT CAUSES AN AURORA?
BACKGROUND
All the energy from the Sun is being harnessed in our own atmosphere, and is causing
great amounts of energy to flow or electric currents to flow around our near space
atmosphere. The energy carried by the solar wind can enter the magnetosphere. Here
the energy is converted into electric currents and electromagnetic energy and
temporarily stored. This higher energy state of the magnetosphere is unstable and the
energy of the currents can be released suddenly. Some of this energy accelerates
electrons in the magnetosphere and causes them to spiral down the Earth’s magnetic
field into the atmosphere,
emitting this energy,
where they produce the
aurora. The most common
one is an oxygen atom.
The particles, the
electrons come smashing
in from outside our
immediate atmosphere
and collide with these
oxygen atoms and cause
them to get excited and
then as they relax back to
their beginning state they
let out light. Oxygen tends
to let out a green light, although sometimes it can let out red. Nitrogen will let out a blue
light. And when all these colors mixed together you can get beautiful purples, mauves,
even white. So you can get some really spectacular colors in the sky, called Aurora
Borealis and Australis or Northern, Southern Lights.
When fast-moving electrons from the Earth's magnetosphere collide with oxygen and
nitrogen atoms the result is the aurora borealis or 'northern lights.' 'Excited' by the
transfer of energy, the air molecules emit light as they 'calm down' and return to their
normal state. Auroras occur in upper atmosphere between 60 and 200 miles (about 95
to 320 kilometers). The aurora cannot be seen in the daytime since it is much fainter
than sunlight.
BENCHMARKS:
BY THE END OF GRADE 8
•
Energy appears in different forms and can be transformed within a system.
Motion energy is associated with the speed of an object. Thermal energy is
associated with the temperature of an object. Gravitational energy is associated
with the height of an object above a reference point. Elastic energy is
associated with the stretching or compressing of an elastic object. Chemical
energy is associated with the composition of a substance. Electrical energy is
associated with an electric current in a circuit. Light energy is associated with
the frequency of electromagnetic waves. 4E/M4*
Light and other electromagnetic waves can warm objects. How much an object's
temperature increases depends on how intense the light striking its surface is, how long
the light shines on the object, and how much of the light is absorbed. 4E/M6**
BY END OF GRADE 12
•
When energy of an isolated atom or molecule changes, it does so in a definite
jump from one value to another, with no possible values in between. The change
in energy occurs when light is absorbed or emitted, so the light also has distinct
energy values. The light emitted or absorbed by separate atoms or molecules (as
in a gas) can be used to identify what the substance is. 4E/H5*
ACTIVITIES FOR APPLICATION:
ENGAGE:
WHAT CAUSES THE AURORA?
Using the content above describe the event that causes an aurora to be seen in the
higher latitudes or as an intense storm that can be seen as far south as Texas.
Emphasize that the particles from the sun are not the direct cause of the aurora, but the
oxygen and nitrogen in the earth’s atmosphere that ultimately emit the photons that
cause the colors of the aurora. Use the Illustration above to describe the colors of the
aurora and what causes them. You can use the scientist’s description of the Aurora in
the Space Weather Media Viewer to answer questions.
http://sunearth.gsfc.nasa.gov/spaceweather/FlexApp/bindebug/index.html#app=d1c&7f6c-selectedIndex=3
EXPLORE:
This is a kinesthetic activity designed to have students act out a solar storm to
understand at the most concert level what causes an Aurora.
MATERIALS:
•
•
•
Yarn to connect field line of the magnetosphere.
Image of the Sun, Earth and a solar flare or coronal mass ejection (CME)
Red, blue and green streamers
SCRIPT:
•
•
You are the S UN - a medium size star that is 93 million miles from earth. You
provide all of the heat and light we need to sustain life.
You are a S OLAR F LARE - electrified gases or plasma are emitted from the sun
when magnetic energy that has built up and is suddenly released.
W HEN THE SUN IS READY PUSH THE SOLAR FLARE TOWARD EARTH.
•
•
The students who represent the M AGNETOSPHERE should now hold the lines of
the magnetosphere to protect the earth (yarn). The magnetosphere is that area
of space, around the Earth, that is controlled by the Earth's magnetic field. Did
you know that the Earth's environment extends all the way from the sun to the
Earth and beyond? It is not an empty wasteland of space. Instead, near-Earth
space is full of streaming particles, electromagnetic radiation, and constantly
changing electric and magnetic fields. All of these things make up our
magnetosphere. The magnetosphere helps to protect our Earth from the danger
of the Sun's solar wind.
As the solar flare touches the magnetosphere the students pull back as far as
they can. The oxygen and nitrogen become excited within the field lines! Jump
around but don’t break from the field lines or touch earth!! Become excited!
OXYGEN- HOLDING RED AND GREEN STREAMER
NITROGEN HOLDING BLUE STREAMER
All magnetosphere students take a deep breath and relax to their original positions.
Oxygen and nitrogen wave the streamers- THE AURORA
HAVE THE STUDENTS ARRANGE THEMSELVES AS SEEN IN THE DIAGRAM BELOW :
EXPLAIN:
Students can use the illustration, answers by the scientist and the kinesthetic activity as
the content they need to describe what causes an Aurora. Students should use any
type of artistic media to develop their own aurora display. This can be done in small
groups or as individuals.
ELABORATE:
THE MATH CONNECTION:
Scientists construct a timeline to investigate how natural phenomena change in time.
This is often the first step in identifying their causes.
Math Activity provided by Space Mathematics-Dr. Sten Odenwald
http://www.nasa.gov/pdf/361684main_SMI_Problem11.pdf
HERE'S HOW TO DO IT !
15:21
A solar flare erupts on the Sun
15:30
A disturbance is detected on Earth
How many minutes later was the Earth disturbance witnessed after the flare erupted?
15hours 30minutes
- 15hours 21minutes
------------------------------------9 minutes later.
Now you try!
Day Time
Tuesday 4:50 PM
Thursday 3:36 AM
Thursday 5:20 AM
Thursday 5:35 AM
Thursday 11:29 AM
Thursday 2:45 PM
What Happened
Gas eruption on Sun
Plasma storm reaches Earth.
Storm at maximum intensity.
Auroral power at maximum.
Aurora power at minimum.
Space conditions normal
1) How much time passed between the solar gas eruption and its detection near Earth?
2) How long after the plasma storm reached Earth did the aurora reach maximum
power?
3) How long did the storm last near Earth from the time the plasma was detected, to
the time space conditions returned to normal?
EXTRA FOR EXPERTS!
If the Earth is 150 million kilometers from the sun, how fast did the storm travel from
the Sun in kilometers per hour?
Another Space Math Activity provided by Space Mathematics-Dr. Sten Odenwald
Height of an Aurora: http://www.nasa.gov/pdf/361684main_SMI_Problem11.pdf
EVALUATE:
Students will be predicting when a solar storm will occur and when they can see an
aurora through their Space Weather Action Center http://sunearthday.nasa.gov/swac .
As they develop their own script about a solar storm they can include a special feature
report about the aurora. Include:
1. Where and When an Aurora can be seen.
2. Colors vs. Intensity of the solar storm.
3. Height of the aurora. (Space Math activity - Height of an Aurora:
http://www.nasa.gov/pdf/361684main_SMI_Problem11.pdf )