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LOOKING UP (What Do We See?). Information from the Cosmos. Ordinary matter (meteors, cosmic rays, lunar rocks) Neutrinos (Sudbury Neutrino Observatory!) http://www.sno.phy.queensu.ca/ Gravitational waves. But most important of all. L I G H T !
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LOOKING UP (What Do We See?)
Information from the Cosmos • Ordinary matter (meteors, cosmic rays, lunar rocks) • Neutrinos (Sudbury Neutrino Observatory!) • http://www.sno.phy.queensu.ca/ • Gravitational waves
But most important of all LIGHT! Light ofall colours, that is, even those which are not visible to the human eye!
Start with Visible Light Imagine the Earth perpetually shrouded in clouds. Suddenly the clouds lift. What do you see?
1. Conspicuous Objects • The Sun! - essentially invariable in appearance, except for eclipses and (rare) large sunspots • The Moon! – very different: constantly changing • The stars! – in immutable, apparently unchanging patterns (the constellations)
Why the Phases? (Here we see Earth and theMoon from a spacecraft near Mars.)
Why the Lunar Phases? NOT the shadow of the Earth! Merely changing perspectives. See simulations in class! And visit http://antwrp.gsfc.nasa.gov/apod/image/0709/lunation_ajc.gif
Yet More • We note that the individual stars are not identical. What does this tell you? [brainstorm time!] • There are star-like objects that wander about, in complex but ever-repeating ways –planets.
Still More …the Milky Way