Solar system – 9 planets & 1 star

Stars emit light, planets reflect this light

Solar systems are in galaxies which are in the Universe

Comets (rock and ice) have long elliptical orbits around Sun

Life cycle of stars – differs for massive & small stars

Red-shift – evidence for fast expansion of galaxies

History of the Universe – Big Bang or Steady State

Future of the Universe – Big Crunch or Eternal Expansion

SETI – Radio signals, laser signals, collect photos & samples