Presentation on theme: "Class Update Observations Friday, Mar. 20 8-9:30pm University of Minnesota (Telescopes & Star Gazing, NO MOON) PRINT VERIFICATION SHEET from calendar Test."— Presentation transcript:
Class Update Observations Friday, Mar :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 pm 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 6pm Journey to Space Omnitheater movie 7pm entrance to Space exhibit Parking $5 between Exchange and Eagle ($9-$12 at museum) Parking location: Meet Raquel in lobby at 5:30pm RSVP required ( 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
Sun Why does Sun look bigger than other stars? It is close.
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 10 6 km = 1.4 million km ( 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 = km (8000 miles) Recall scaling: beach ball / BB
Sun – A Plasma Hot, ionized gas Solid, liquid, gas, plasma Copyright1994 General Atomics
Examples of Plasmas 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)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 – General Information Sun’s Mass ~10 30 kg (~million Earths, know this) (Earth is ~6x10 24 kg or 13x10 25 lbs) Most mass of solar system (99.8%) (know this) Mass of Sun = 2 x kg (4 x lbs) Largest Star Mass ~= up to 265 times the mass of Sun (maybe not more than 150 times)
How hot is the Sun?
Sun – General Information Sun’s Temperature Surface: ~5800 K (~ o F) mergencymanagement/planning/Pages/HeatWave. aspx... Sun’s T Surface: ~5800 K (~ o F) Core: ~ K (~ o F)
What is the Sun’s composition?
Sun – General Information 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)
Looking at the Sun
"Copyright Association of Universities for Research in Astronomy Inc. (AURA), all rights reserved." "National Optical Astronomy Observatories, National Science Foundation" Solar Terminology Photosphere Visible surface of the Sun
Corona Hot gas around the Sun
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" Sunspot
"Copyright Association of Universities for Research in Astronomy Inc. (AURA), all rights reserved." "National Optical Astronomy Observatories, National Science Foundation" Today’s sunspots
Sunspot Cycle ~11 year cycle Numbers of sunspots vary Solar minimum Solar maximum Current solar cycle at:
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 Prominence
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 Flare
Coronal Mass Ejection (CME) (go to “Amazing CME” - blue) (go to “Several CMEs and one proton storm” - red) Large ejection of EM radiation and charged particles Break of a prominence Big area of Sun
Difference Between a CME & Solar Flare Comparison video of a Solar Flare (small, localized region) and a CME (big region of the Sun)
Coronal Mass Ejection – Problems for Earth and Earthlings (http://hesperia.gsfc.nasa.gov/sftheory/spaceweather.htm)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
Mash light elements together Form heavier elements + release energy EX: 4H 1He + 2e e + energy more mass less mass E = mc 2 Sun is giving off mass and losing gravity. Fusion will make the Sun larger over a long time period. Fusion Fun fact: The sun loses mass, about 4 million tons every second!
Sun-like stars: H He… (Li, Be, B)… C Fusion
Fusion Summary Gravity pulls in, energy from fusion pushes out Star is balanced Fusion: lighter elements heavier elements + energy E = mc 2 Sun like stars produce He…C
Solar Wind Continuous flow of particles from Sun - Protons, electrons, ions
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 Charged particles spiral toward poles Energy released Charges interact with Earth’s atmosphere Earth’s magnetic field
MMS Spacecraft Launched March 12, Earth’s magnetosphere as a laboratory to study the microphysics of magnetic reconnection
CRT and Magnet https://www.youtube.com/watch?v=YbzBTdU7iRU
APOD - Edmonton
APOD - Quebec
APOD - Finland
APOD - Missouri
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
short motion clip
Space Weather Prediction Center
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