Chapter Learning Goals
- What is our place in the Universe?
o Earth, Solar System, Milky Way Galaxy, Local Group, Local
- How did we come to be?
o At the big bang, He and H were created. They eventually formed
heavier elements which compose the planets, and all the living
constantly recycled through the death and birth of stars (on a
large scale) or through the decomposition, and reformation of
organisms on the planet (on a microcosmic scale)
- How can we know what the Universe was like in the past?
o By looking at distant stars, we can see how the universe was like
in the past as the light takes a long amount of time to reach our
eyes. Further we look into the universe, the farther we look back
in time, up to 13.7 Billion years (the age of the universe)
- Can we see the entire universe?
o No, we can only see up to 13.7 billion light years away as that is
the age of the universe. Any further, and the universe does not
exist, at least not to our perception
- How big is Earth compared to our solar system?
o Really damn small
- How far away are the stars?
o Minimum 4 light years (not including the sun), most are much
- How big is the Milky Way Galaxy?
o Huge; 100 billion stars
- How big is the Universe?
o 13.7 Billion light years in size
- How do our lifetimes compare to the age of the universe?
o If the lifespan of the universe was one year, our existence would
be about a fraction of a second
- How is Earth moving in our solar system?
o It revolves around the sun, and revolves on its own axis.
- How does our Solar System move in the galaxy?
o Really fast, but it takes 230 million years for us to orbit it
- How do galaxies move?
o Galaxies are moving away from us at random patterns
- Are we ever sitting still?
o No, never
- How has Astronomy changed human history?
o It has changed our beliefs of creation, divinity, and life as we
know it. Examples ; Earth-&HQWHUHGXQLYHUVH´FHOHVWLDOVSKHUHµ
- What does the universe look like from Earth?
o White band = Milky Way, constellations around the sky on
one half of the CS as the dome of our Local Sky, where horizon =
boundary btwn eath and sky, Zenith is directly above, meridian
goes from south, zenith, north
- Why do stars rise and set?
o (DUWK·VURWDWLRQPDNHVWKHPDSSHDUWRGRVRCircumpolar stars
do not rise and set, but rather make circles in the sky
- Why do the constellations depend on latitude and time of year?
o Each place along our orbit gives us a different perspective s of the
stars. Latitude also varies the orientation of the horizon to the sky.
Longitude has no effect on constellations because we rotate
through all longitudes each day.
- What causes seasons?
- How do we mark the progression of the season?
o Summer Solstice = Longest Day ; Winter Solstice = Longest Night
o Spring/Fall Equinox = Equal Day Time and Night Time
o It precesses every 26,000 Years, though the tilt remains the same,
the orientation of the axis changes.
- Why do we see phases of the moon?
o Because the moon reflects certain parts of the sun at different
times in the sky; we see all phases of the illumination
- What causes eclipses?
o Lunar Eclipse = Sun Æ Earth Æ Moon (Red Moon
o Solar Eclipse = Sun Æ Moon Æ Earth (Annular Eclipse)
- What was mysterious about our universe?
o RETROGRADE MOTION
o Also, Sun Centered Universe was rejected because
Greeks did not see STELLAR PARALLAX ; could not believe
that stars were so far away that it would be undetectable
Therefore the belief that Earth was stationary would make
sense Æ FALSE TOTALLY FALSE
What is our place in the universe: earth, solar system, milky way galaxy, local group, local. How did we come to be: at the big bang, he and h were created. They eventually formed heavier elements which compose the planets, and all the living. 47,382843985,309 0,70,2,/04189,789:11. 8 constantly recycled through the death and birth of stars (on a large scale) or through the decomposition, and reformation of organisms on the planet (on a microcosmic scale) Further we look into the universe, the farther we look back in time, up to 13. 7 billion years (the age of the universe) Can we see the entire universe: no, we can only see up to 13. 7 billion light years away as that is the age of the universe. Any further, and the universe does not exist, at least not to our perception. How big is earth compared to our solar system: really damn small.