Astronomy Lecture
(to be used with the Astronomy Powerpoint)
slide 1
Solar system: on the outer spirals of the Milky Way Galaxy
Origins (watch minute 2-12)
https://www.youtube.com/watch?v=71jPKLuzrqM&list=PLIRIR2NJr39Qb9a0eoMDGv
bX6_gdzjN8l&index=4
for the next link go to Stellar Evolution, then How a Star Forms with a Solar System
http://ww2.valdosta.edu/~cbarnbau/astro_demos/frameset_seasons.html
The Solar System is the sun and everything that orbits it, or everything that is bound by
the sun’s gravity.
Solar System Overview: https://www.youtube.com/watch?v=KsF_hdjWJjo
Member’s of the Solar System https://solarsystem.nasa.gov/planets/
The Sun is the center of the Solar System and the Oort Cloud is the outer edge.
Solar System’s Age: (we know this from meteorite ages)
4.6 Billion years
4 Billion 600 million years
4,600,000,000
4.6 X 10 9
Solar System’s Size: (we know this because of telescopes like the Hubble)
about 2 light years wide
2 x 1016 meters
20,000,000,000,000,000 meters
Scale of the Universe: this website compares sizes of objects, and explains distances
http://htwins.net/scale2/
slide 2
Earth: our home in space, 150 million kilometers or 93 million miles from the sun.
Day: rotation 24 hours (to spin in a circle like a top, causes night and day)
Day is when we face toward the Sun, Night is when we face away. Length varies
around the planet based on latitude (north /south).
Half of Earth is always in nighttime, half is always in daytime.
Earth rotates towards the east, making the sun rise in the east and set in the west.
Sunrise and sunset are a permanent ring around the planet making the boundary
between day and night.
Year: orbit/revolution: going around the Sun in a large oval 940 million kilometers or 584
million miles long
365 days (meaning the Earth spins in a circle like a top 365 times every time the
Earth goes around the sun once)
NASA https://solarsystem.nasa.gov/planets/earth
slide 3-4
Seasons are caused by the tilt of the earth’s axis (an imaginary line through Earth’s
geographic north and south pole), the tilt was caused by planetessimal Thea’s impact.
Seasons animations
http://highered.mheducation.com/sites/007299181x/student_view0/chapter2/seasons_inte
ractive.html
http://astro.unl.edu/naap/motion1/animations/seasons_ecliptic.html
http://esminfo.prenhall.com/science/geoanimations/animations/01_EarthSun_E2.html
http://www.thisiscolossal.com/2013/08/breathing-earth/
In summer it’s hot because the sun’s light is direct, gets trapped on Earth and cannot
bounce back into outer space.
In winter it’s cold because the sun’s light is indirect, bounces off of the Earth, and is lost
to outer space.
The seasons are opposite on the Northern and Southern Hemispheres. It’s summer in the
north when it’s winter in the south. It’s summer in the south when it’s winter in the
north.
Summer solstice: the longest day of sunlight. June 20-22nd in the Northern Hemisphere
and December 20-23rd in the Southern Hemisphere.
Winter solstice: the longest night of darkness. December 20-23rd in the Northern
Hemisphere and June 20-22nd in the Southern Hemisphere. Opposite of the summer
solstice.
Spring and Fall equinox: a 12 hour day and 12 hour night on the entire planet.
Seasons don’t change on the equator. (It’s normally hot all year round. It might change
from dry to wet or be cold all year round in high elevations, like the Andes.)
On the poles: in summer the sun rises for two months before it sets. In winter the sun sets
and doesn’t rise for two months.
Where we live is right between the two and enjoys 4 even seasons.
slide 5-9
Moon: created 50 million years after Earth from planetessimal Thea’s impact. The moon
is the “splash” that gravity pulled into a ball. The moon orbits (revolves) around the
Earth.
Formation: Origins (minute 20-30)
https://www.youtube.com/watch?v=71jPKLuzrqM&list=PLIRIR2NJr39Qb9a0eoMDGv
bX6_gdzjN8l&index=4
The moon reflects the light of the sun on its daytime side. As the moon orbits the Earth
we see a changing amount of the moon daytime surface causing us to see the moon in
phases here on earth.
slide 6-7
Moon Phases: how much of the daytime or nighttime side of the moon we see.
Moon phases animation: http://astro.unl.edu/naap/lps/animations/lps.swf
A month used to stand for a set of moon phases, 29-30 days. The moon goes through all
its phases 12 times a year. That is why we have 12 months. The Roman empire took 2
days from February and put one on July for Julius Ceasar, and one on August for
Augustus Ceasar. The names for our months come from the Romans (so do the planet
names).
NASA https://solarsystem.nasa.gov/planets/moon
slide 10-12
The Sun: our star that holds the Solar System together.
Nuclear fusion: Origins (minute 32-40)
https://www.youtube.com/watch?v=kdhhbV4GhJ8&index=1&list=PLIRIR2NJr39Qb9a0
eoMDGvbX6_gdzjN8l
Periodic Table interactive website http://www.ptable.com/
Supernova: an exploding star (that has fused too much Iron)
Nebula: the cloud of debris caused by a supernova
Gravity crushes nebula’s back into stars.
NASA https://solarsystem.nasa.gov/planets/sun
slide 12
Solar Flares, The Solar Wind, and Auroras
Solar Flares: giant explosions on the surface of the Sun (larger than Earth) that shoot out
charged particles (like invisibly tiny magnets) called the Solar Wind
Magnetosphere: Earth’s magnetic field caused by Earth’s liquid Iron (Fe) core.
The Earth has magnetic poles that are close to Earth’s Geographic poles (axis). The
magnetic poles move, the Geographic ones do not.
Compasses are attracted to the Earth’s magnetic field.
Origins clip (minute 13-20)
https://www.youtube.com/watch?v=71jPKLuzrqM&list=PLIRIR2NJr39Qb9a0eoMDGv
bX6_gdzjN8l&index=4
Auroras: caused by Earth’s magnetosphere (Earth’s magnetic field)
Explanation: https://www.youtube.com/watch?v=lT3J6a9p_o8
For outer space: https://www.youtube.com/watch?v=88uS_pIon_s
slide 13-14
Speed of light: the fastest thing in the universe. Light can travel from the Sun 93 Million
miles to the Earth in 8 minutes. It would take a car driving a 70 mph 360 years to drive
that distance non-stop.
about 300,000,000 meters per second (m/s)
3 x108 meters per second (m/s)
671 million miles per hour (mph)
6.71×108 mph
671,000,000 mph
186,000 miles per second
1.86 x 105 miles per second
Planets: means wanderer in Greek because planets move in different directions from the
stars in the night sky, but planets are defined by having enough gravity (mass) to pull
themselves into a ball and turns everything else in their orbit into a moon.
slide 15-16
Mercury: the closest planet to the sun
It has a day (rotation) that is longer than it’s year.
It has no atmosphere or moons.
It has the most extreme temperature change from night to day of any planet,
ranging from −173 °C; −280 °F at night to 427 °C; 800 °F during the day.
NASA https://solarsystem.nasa.gov/planets/mercury
slide 17-18
Venus: 2nd closest planet to the sun, closest planet to Earth, and closest in size to Earth.
Venus is the hottest planet in the Solar System, because of it’s greenhouse effect.
Venus has an atmosphere of acidic clouds that rain sulfuric acid.
Venus has no moons.
Greenhouse effect:
http://earthguide.ucsd.edu/earthguide/diagrams/greenhouse/
https://phet.colorado.edu/en/simulation/greenhouse
NASA https://solarsystem.nasa.gov/planets/venus
slide 19-22
Mars
NASA https://solarsystem.nasa.gov/planets/mars
Mar’s Moons https://www.youtube.com/watch?v=Pw0IZg7_4mo
slide 23
Asteroid Belt: between Mars and Jupiter. Most meteors come from the asteroid belt.
Asteroid: a rock in the asteroid belt
Meteoroid: a rock knocked out of the asteroid belt flying through space
Meteor: a rock the is burning up from friction with the Earth’s atmosphere as it
crashes toward Earth
Meteorite: the remains of a meteor on the surface of Earth
NASA https://solarsystem.nasa.gov/planets/asteroids
https://solarsystem.nasa.gov/planets/meteors
slide 24-29
Jupiter:
NASA https://solarsystem.nasa.gov/planets/jupiter
slide 30-32
Saturn:
NASA https://solarsystem.nasa.gov/planets/saturn
slide 33-34
Uranus:
Uranus’ axis is so tilted, it rolls on its orbit like a ball, instead of spins like a top.
No weather
NASA https://solarsystem.nasa.gov/planets/uranus
slide 35-38
Neptune:
NASA https://solarsystem.nasa.gov/planets/neptune
Neptune’s Moons https://www.youtube.com/watch?v=cR9uphgMZ8U
slide 39-40
Kuiper Belt and Pluto
NASA https://solarsystem.nasa.gov/planets/dwarf
https://solarsystem.nasa.gov/planets/kbos
New Horizons photos of Pluto published 9-10-15!
http://www.nasa.gov/feature/new-pluto-images-from-nasa-s-new-horizons-it-scomplicated
Moons of Pluto https://www.youtube.com/watch?v=pOI2Pv1iWy4
slide 41
Meteors: see asteroid belt
slide 42
Comets:
NASA https://solarsystem.nasa.gov/planets/comets
Oort Cloud
NASA https://solarsystem.nasa.gov/planets/oort
slide 44-47
Galaxy: Milky Way (we’ll study for later)
Size:
120,000 Light years
1.2 x 1021 meters
120,000,000,000,000,000,000 meters
Age: about as old as the universe
Solar System takes 225 to 250 million years to orbit once around the center of the Milky
Way
200 to 400 billion stars
2 x 1011 to 4 x 1011
200,000,000,000 to 400,000,000,000
slide 48
Black Hole
slide 49-54
Nebula
Slide 55
Planetary Nebula: what our sun will do after it becomes a red giant
slide 56-59
Stars
slide 60
Constellations:
valdosta
slide 62-63
our sun red giant to white dwarf
slide 64
supernova
slide 65-67
Hubble
slide 68
Universe: the entirety of space (everything we know both big and small)
(we’ll study more later)
Big Bang
https://www.youtube.com/watch?v=wNDGgL73ihY
Quark Gluon Plasma
Quarks: (Up +2/3, Down -1/3)
Proton: 1= 2/3+2/3-1/3
Neutron: 0= 2/3-1/3-1/3
proton=up+up-down
neutron=up-down-down
Beta Decay (radioactivity)
Neutron- Electron= Proton
0- (-1)= 0+1 =1
https://phet.colorado.edu/en/simulation/beta-decay
Age of the Universe:
13.7 Billion years
13,700,000,000
Size:
9.3 x 1026 light years
930,000,000,000,000,000,000,000,000 light years
no slide
Light year: how far light travels in a year.
Distances from the Sun — the General Idea
http://ww2.valdosta.edu/~cbarnbau/astro_demos/frameset_seasons.html
9.46 trillion kilometers (km)
9.46 x1012 km
9,460,000,000,000 km
5.9 trillion miles
5.9 x 1012 miles
5,900,000,000,000 miles
slide 69-81