cosmology

Question 1

what is the Big Bang theory?

Answer 1

• the universe began from a small region that was hot and dense
• then there was a giant explosion which is known as the Big Bang
• it caused the universe to expand from a single point cooling as it does
• each point expands away from others
• the universe continues to expand

Question 2

what happens as the universe expands?

Answer 2

all points become further apart by the same amount

the space has expand and therefore the density of the galaxies falls

Question 3

what are the main pieces of evidence from the Big Bang theory?

Answer 3

galactic red shift

comic microwave background

Question 4

what is red shift?

Answer 4

• on the visible light spectrum the red wavelengths are the longest
• chemicals can absorb wavelengths
• some light doesn’t get absorbed and it creates “lines” of light on the spectrum
• when looking at light spectrum from distant galaxies the lines on the spectrum are shifted toward the red end causing red shift

Question 5

why does red shift happen?

Answer 5

all of the light waves get stretched as they make their way toward the earth
distant galaxies emitting light are moving away from us and the waves are getting stretched

Question 6

why does red shift provide evidence that the universe is expanding?

Answer 6

the spectral lines from distant galaxies move because they are stretched by the expanding space between galaxies
and the light spectrums from distant galaxies are more red shifted than closer ones

Question 7

what is the cosmic microwave background radiation?

Answer 7

a type of eletromagnetic radiation which is remnant from the early universe
the thermal radiation emitted from the explosion is in the microwave region, it would have been in the high energy radiation but due the expansion the wavelength of the radiation increases, now its at the microwave region