Transcript Sun - MCTCteach

• Observations
• Friday, Mar. 20
Class Update
• 8-9:30pm University of Minnesota (Telescopes & Star Gazing, NO
MOON) PRINT VERIFICATION SHEET from calendar
• Test 2 on Tuesday, March 24 (in 1 week)
• 40 multiple choice questions
• 20 points possible for Mars/Saturn Writing Assignment (see
calendar for more details)
• Need to type/print and have it ready at the beginning of
the test
• Test covers material from Feb. 12 to Mar. 19
• Study Session with Gus: Thur, Mar. 19 3-5pm Room S3500
• Studying
• 1. D2L Quizzes 5, 6, 7, 8 (10+ questions on test)
• 2. Review Lecture Objectives (file on Mar. 24 on calendar)
Class Update
• Science Museum of Minnesota “Space: An Out of Gravity
Experience” FREE!
• Thursday, May 7 5:30pm to 8:30pm (museum open until 9pm)
• Reserve the date on your calendar
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6pm Journey to Space Omnitheater movie
7pm entrance to Space exhibit
http://www.smm.org/space
Parking $5 between Exchange and Eagle ($9-$12 at museum)
Parking location: http://tinyurl.com/mdw8ush
Meet Raquel in lobby at 5:30pm
RSVP required (email notice coming soon)
FREE for astronomy students; other family or friends are $19/person
(normal price is $31/person)
Sun
• A few traits of our sun
• Fusion: What powers our sun
• Aurora
Sun
A star like billions of other stars
http://antwrp.gsfc.nasa.gov/apod/ap100817.html
Sun
It is close.
Why does Sun look bigger than other stars?
http://antwrp.gsfc.nasa.gov/apod/ap100817.html
How Big is the Sun?
Sun – Average Star
(know the sun is average size, but don’t need to know numbers)
Diameter of Sun
= 1.4 x 106 km = 1.4 million km
(900 000 miles)
Largest Star Diameter
~= 1400 to 2600 times the size
of Sun (maybe not more than
1500 times)
~100 Earths across the
diameter of the Sun
(know this for test)
Diameter of Earth
= 13 000 km (8000 miles)
Recall scaling:
beach ball / BB
http://learn.arc.nasa.gov/planets/0/
Sun – A Plasma
Hot, ionized gas
Solid, liquid, gas, plasma
Copyright1994 General Atomics
Examples of Plasmas
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•
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Plasma ball
Rocket exhaust
Flames (1500F+)
Lightning
Sun
Why Does the Sun Really Shine?
Does the Sun Rotate?
Surface Rotation
• Earth rotates (See globe)
• Sun also rotates – play video
(See windows2 universe)
Surface Rotation
But Sun is a plasma.
Equatorial zone rotates
faster than zones
north and south.
How much does the Sun weigh?
What is the Sun’s mass?
Sun’s Mass
~1030 kg (~million Earths, know this)
(Earth is ~6x1024kg or 13x1025lbs)
Most mass of solar system (99.8%) (know this)
Mass of Sun
= 2 x 1030 kg (4 x 1030 lbs)
Largest Star Mass
~= up to 265 times the
mass of Sun (maybe not
more than 150 times)
Sun – General Information
How hot is the Sun?
Sun’s T
Temperature
Surface: ~5800 K
(~10 000o F)
Core:
~15 000 000 K
(~27 000 000o F)
http://www.a2gov.org/government/safetyservices/e
mergencymanagement/planning/Pages/HeatWave.
aspx...
Sun – General Information
What is the Sun’s composition?
Sun’s Composition
Cecilia Payne (1920’s)
~90% H, ~10% He
(9 atoms of H to 1 atom of He)
a few other elements like C, Si, Fe
Note: Sometimes you hear 75%:25%
Counting vs weighing…
Sun – General Information
Sun’s Composition
Counting: ~90% H, ~10% He (9 H to 1 He)
By mass: ~75% H, ~25% He
(Learn these)
Sun – General Information
Looking at the Sun
Solar Terminology
Photosphere
Visible surface of the Sun
"Copyright Association of Universities for
Research in Astronomy Inc. (AURA), all
rights reserved." "National Optical
Astronomy Observatories, National Science
Foundation"
Corona
Hot gas
around the
Sun
http://science.nasa.gov/newhome/headlines/images/eclipse/beautifulcorona_big.jpg
Sunspot
• Dark “storm” on photosphere
• Cooler than surrounding area
• Concentration of magnetic field
"Copyright Association of Universities for
Research in Astronomy Inc. (AURA), all
rights reserved." "National Optical
Astronomy Observatories, National Science
Foundation"
Today’s sunspots
http://sohowww.nascom.nasa.gov/
"Copyright Association of Universities for
Research in Astronomy Inc. (AURA), all
rights reserved." "National Optical
Astronomy Observatories, National Science
Foundation"
Sunspot Cycle
~11 year cycle
Numbers of sunspots vary
Solar minimum
Solar maximum
Current solar cycle at:
http://www.swpc.noaa.gov/products/solar-cycle-progression
Prominence
• Relatively cool, dense
cloud of gas/plasma
•
•
•
•
•
Hangs in the corona, still connected to Sun
Lasts days to weeks
Supported by magnetic fields
Bright when seen on the sun’s edge
Play eit solar rotation
Flare
• Rapid release of energy
– Seconds long
• From a localized region
• Made of EM radiation, energetic particles
– EM = electromagnetic; this will be covered
more in future lectures
– EM Spectrum includes radio, microwave,
infrared, visible, ultraviolet, x-rays, gamma
rays; light particles at different wavelengths
Coronal Mass Ejection (CME)
Large ejection of EM radiation and
charged particles
Break of a prominence
Big area of Sun
http://sohowww.nascom.nasa.gov/gallery/Movies/flares.html
(go to “Amazing CME” - blue)
(go to “Several CMEs and one proton storm” - red)
Difference Between a CME & Solar Flare
Comparison video of a Solar Flare (small,
localized region) and a CME (big region of
the Sun)
http://cse.ssl.berkeley.edu/coronalweather/CMEsFlares/
Coronal Mass Ejection –
Problems for Earth and Earthlings
(http://hesperia.gsfc.nasa.gov/sftheory/spaceweather.htm)
• Communications – Radio, TV, Cell phones, Over-the-Horizon radar,
jamming of air-control radio frequencies (long distances)
• Navigation Systems – LORAN, GPS – degrades orbit
• Satellites –
Heat atmosphere and expand it, changing satellite orbit
Electronics fried by energetic particles
• Radiation Hazards to Humans – astronauts going to Moon or Mars,
airplane crews and passengers (small)
• Electric Power grids – ex 1989 in Canada
• Global Climate affected by solar cycle maximum & minimum
– Link between solar minimum and “the little ice age” 1500 to 1850
• Biology – ex homing pigeons, dolphins, whales (use Earth’s
magnetic field to guide them)
Star Power
Or How I Learned to Love
Fusion
•Gravity pulls in
•Energy from fusion
pushes out
Balance Hydrostatic Equilibrium
Fusion
•Mash light elements together
•Form heavier elements + release energy
EX: 4H
 1He + 2e+ + 2e + energy
more mass 
less mass
E = mc2
Fun fact: The sun loses mass, about 4
million tons every second!
Sun is giving off mass and losing gravity. Fusion will make the Sun larger over a
long time period.
Fusion
•Sun-like stars: H  He… (Li, Be, B)… C
Fusion Summary
Gravity pulls in, energy from fusion pushes out
Star is balanced
Fusion: lighter elements  heavier elements + energy
E = mc2
Sun like stars produce He…C
Aurora
APOD - Wisconsin
Aurora Borealis
(Northern Lights)
Aurora Australis
(Southern Lights)
APOD - Wisconsin
What causes the aurora?
Solar Wind
• Continuous flow of particles from Sun
- Protons, electrons, ions
http://learn.arc.nasa.gov/planets/0/
Solar wind
Earth’s
magnetic
field
Solar wind
Earth’s
magnetic
field
Charged
particles
spiral
toward
poles
Solar wind
Earth’s
magnetic
field
Charged
particles
spiral
toward
poles
Charges
interact
with Earth’s
atmosphere
Solar wind
Earth’s
magnetic
field
Charged
particles
spiral
toward
poles
Energy
released
Charges
interact with
Earth’s
atmosphere
MMS Spacecraft
• Launched March 12, 2015
• http://mms.gsfc.nasa.gov/
• Earth’s magnetosphere as a
laboratory to study the microphysics
of magnetic reconnection
http://mms.gsfc.nasa.gov/
CRT and Magnet
https://www.youtube.com/watch?v=YbzBTdU7iRU
APOD - Edmonton
APOD - Quebec
APOD - Finland
APOD - Missouri
APOD - Quebec
APOD - Quebec
APOD - Oklahoma
APOD - Washington
APOD – Alaska – Comet Ikea-Zhang
APOD - Norway
APOD - ISS
Aurora from the International
Space Station
https://www.youtube.com/watch?v=FG0fTKAqZ5g
Aurora on Other Planets
http://antwrp.gsfc.nasa.gov/apod/ap011114.html
short motion clip
Space Weather Prediction Center
http://www.swpc.noaa.gov/SWN/index.html
http://www.swpc.noaa.gov/ovation/
Aurora review
Video
http://climate.gi.alaska.edu/Curtis/pom.jpg
• http://apod.nasa.gov/apod/ap101124.html
• Or http://vimeo.com/16917950
• End
Safe Gazing at the Sun
• Observation March 31 or April 2
• Date depends on weather
• Handout or get information from class website
• Lab Students need to follow the lab prep work on lab
page of website
• Lecture for the day and lab for the week
• ~8:30am to 3:30pm reserve 30 minutes for lecture or 1
hour for lab