Universe Flashcards
What is red shift?
The idea that the universe is expanding shown through light from distance galaxies having lower frequencies than they should or being towards the red end of the spectrum
What is the Doppler effect?
The frequency of the source moving towards you will seem higher and the wavelength shorter
The frequency of the source moving away from you will seem lower and the wavelength longer
Happens with longitudinal and transverse waves
What is the rule for redshift?
The further away the Galaxy is the greater the red shift
Distance galaxies are moving away from us faster than the nearer ones
Proves whole universe is expanding
What is the Big Bang theory?
The theory that all matter and energy in the universe was compressed and exploded from a single point and started expanding
Expansion still going
Why is the Big Bang theory more largely believed than the steady state theory
Scientists detected low frequency electromagnetic radiation coming from all parts of the universe
The discovery of CMBR showed that that much radiation could only have come from a large explosion
What are the limitations to the Big Bang theory?
The universe expansion should be slowing down but it’s speeding up
No one knows what causes the big explosion or what conditions were like before it
What is the theory behind the Doppler effect?
When something that emits waves moves toward you or away from you the wavelengths and frequencies seem different compared to when the source of the waves is stationary
What is the steady state theory?
The theory that the universe has always existed as it is now and always will do
What can we use the current rate of expansion of the universe to estimate?
The age of the universe
Estimate= Big Bang theory happened about 14 billion years ago
How does the Big Bang theory explain CMBR?
Just after the Big Bang the universe was extremely hot so everything emmited high frequency radiation as the universe expanded it cooled and the radiation has dropped in frequency and is now seen as microwave radiation
How does steady state explain the expansion?
Suggesting matter is being created in the spaces as the universe expands
