Memory Anchor:

• Super Challenge:

  Stretch:

  Challenge:

Key Questions:

1. (Physics only) What happens to the red-shift of receding galaxies and why?
   • (Physics only) Astronomers have found that the further from us a star is, the more its light is red-shifted. This tells us that distant galaxies are moving away from us, and that the further away a galaxy is, the faster it's moving away.
2. (Physics only) What is red-shift?
   • (Physics only) Red-shift is the observed increase in a wavelength of light from most distant galaxies.
3. (Physics only) What makes red-shift increase?
   • (Physics only) The further away the galaxies, the faster they are moving and the bigger the observed increase in wavelength.
4. (Physics only) How does red-shift support the Big Bang theory?
   • (Physics only) The observed red-shift provides evidence that space itself (the universe) is expanding and supports the Big Bang theory.
5. (Physics only) What does the Big Bang theory suggest?
   • (Physics only) The Big Bang theory suggests that the universe began from a very small region that was extremely hot and dense.
6. (Physics only) What have scientists observed of distant galaxies since 1998?
   • (Physics only) Since 1998 onwards, observations of supernovae suggest that distant galaxies are receding ever faster.
7. (Physics only) What evidence is there of an expanding universe?
   • (Physics only) The fact that the speed of a galaxy changes as it gets further away supports the idea that the universe is expanding.
8. (Physics only) How does Red-shift provide evidence for the Big Bang model?
   • (Physics only) Astronomers have found that the further from us a star is the more its light is red shifted. This tells us that distant galaxies are moving away from us, and that the further a galaxy is the faster it is moving away. This is evidence for a generally expanding universe. It suggests that everything is moving away from everything else.