4.8.2 Red shift (will come up) P2 Flashcards
What is red-shift
An observed increase in the wavelength of light from distant galaxies
What 2 things can be said about the motion and wavelength of emitted light from a galaxy, the further away it is
The further away a galaxy is, the faster it is moving
The further away a galaxy is, the greater the observed increase in wavelength
What does red shift provide evidence for
Provides evidence that the universe is expanding
Supports the Big Bang theory
What does the Big Bang theory suggest
The entire universe started from a very small, hot and dense region in space
Compare the observed red shift of two galaxies, one further away than the other
The galaxy that is further away is travelling faster
The observed red shift is greater the further away it is
What did scientists observe to provide evidence that the universe is expanding at an ever faster rate
They observed supernovae, which suggested that galaxies are moving away at an even faster rate
Prior to observations of supernovae, what was believed about the rate of expansion of the universe and why
The rate of expansion was expected to occur at an ever slower rate
It was thought that gravitational forces would cause this slowing down
What 2 ideas could explain the universe’s ever increasing rate of expansion
The existence of energy and mass that we cant detect, known as dark matter and dark energy
These ideas are still being developed by scientists and are not yet fully understood
