Cosmology Flashcards
what is a Cephiad Variable?
A star that goes brighter then dimmer and back.
What do astronomers use Cephiad Variables for?
They use these stars to measure how far, distant stars are from earth.
Explain what the steady state model is!
The belief that the universe has always existed and had no beginning. (It is not expanding)
What did Edwin Hubble discover that undermined the steady state model?
He discovered a background noise from space, which was later found out to be remnants of the beginning of the universe. (If the universe is expanding it must have had a beginning)
What is the red shift model?
A model that shows how light bends to form shorter wavelengths at the front of a moving object then at the back.
What colour light is a star moving towards us?
Red
What colour light is a star moving away from us?
Blue
What colour light is a star that is stationary?
It has it’s normal colour based on it’s temperature.
What are the two important observations Hubble made?
That there are many other galaxies other than the Milky Way in the universe. Also that all galaxies are moving farther away from the Milky Way.
What is the source of the cosmic microwave background radiation?
The universe expanding and the remnants of the start to the universe. (The big bang)
How long ago did the big bang occur?
13.7 Billion years ago
What happened when the universe began?
The universe fit inside the palm of persons hand, it then expanded very rapidly releasing lots of radiation and energy.
What does the big bang explain?
It explains how the universe became to be and why there is background noise from space, it also explains why the universe is expanding.
How is the colour of a star determined?
A star’s colour is determined by its temperature and is measured with a spectrometer.
What is the first nuclear reaction in a star?
proton + proton = deuterium + energy
