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USEM 170 : The Sound of Creation. Introduction : The Big Picture. Hierarchy of structures:. Nuclei (particles) Atoms Stars/Planets Galaxies Universe. Atoms: Nuclei: protons neutrons Electrons. Solar magnetic surface storm. Earth. Scale of the Solar System. Earth-moon system…..
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USEM 170 : The Sound of Creation Introduction : The Big Picture
Hierarchy of structures: • Nuclei (particles) • Atoms • Stars/Planets • Galaxies • Universe
Atoms: • Nuclei: • protons • neutrons • Electrons
Scale of the Solar System • Earth-moon system….. • The sun as an orange…. • The nearest star • The galaxy !
Our Galaxy : The Milky Way Milky way galaxy is a complex system • 1011 stars (& planets?) Each with life cycle: birth/life/death • Material between the stars Tenuous gas: clouds; diffuse
Jewel Box Cluster Naked eye stars Eagle Nebula Crab Nebula Our Galaxy Earth = 100 nm = virus Sun = 10 μm = cell Earth orbit = ¼ cm = pin head Solar system = 20 cm = saucer Nearest star = 250 m = lawn Solar system Galaxy Center
The Population of Galaxies Galaxies are a diverse population • Different sizes & shapes & motions different histories? • They tend to form groups pairs clusters; some collide and merge
Galaxies to the horizon The Universe is filled with galaxies • 1011 galaxies visible • More distant ones appear younger look-back time due to finite light speed
SDSS : ⅓ million galaxies 3 billion light years (~20% to “the edge”) Our galaxy is here
Hubble Deep Field ~1500 galaxies Sky area ~2.5×2.5 arcmin ≡ pinhead @ arms-length
Keck/VLT + Cluster Lens SDSS & 2dFGRS HDF “Nearby” galaxies 13.7 Gly 0 The Visible Universe MW galaxy = 20 m = class room MW galaxy = 20 m = class room Local group = 600 m = central grounds Virgo cluster = 15 km = Walmart Coma cluster = 100 km = Culpeper Our Galaxy