The Origin of the Universe

Question 1

The universe is [ ].

Answer 1

Expanding - all its galaxies seem to be moving away from each other

Question 2

Light from other galaxies is [ ]

Answer 2

Red-shifted

Question 3

Different [ ] absorb different frequencies of light

Answer 3

chemical elements

Question 4

Describe red-shift

Answer 4

Each element produces a specific pattern of dark lines at the frequencies that it absorbs in the visable spectrum
When we look at light from distant galaxies we can see the same patterns but at slightly lower frequencies - they’re shifted towards the red end of the spectrum

Question 5

What is the Doppler effect?

Answer 5

When something that emits waves move towards you or away from you, the wavelengths and frequencies of the waves seem different - compared to the source when stationary

Question 6

The frequency of a source moving towards you will seem [ ] and its wavelength will seem [ ]

Answer 6

Higher

Shorter

Question 7

The frequency of a source moving away from you will seem [ ] and its wavelength will seem [ ]

Answer 7

Lower

Longer

Question 8

What type of waves does the Doppler effect have an effect on?

Answer 8

Both longitudinal and transverse

Question 9

What do the measurements of the red-shift suggest?

Answer 9

All the galaxies are moving way from s very quickly. More distant galaxies have greater red-shifts than nearer ones. This means that the more distant galaxies are moving away from us faster than nearer ones.
Therefore this is evidence that the whole universe is expanding

Question 10

What does the expanding of the universe suggest about the origins of the universe?

Answer 10

That there was a big explosion - the big bang

Question 11

Describe the Big Bang theory

Answer 11

All the matter and energy in the universe must have been compressed into a very small space. It then exploded from that point and started expanding.

Question 12

What can we use the current rate of expansion to estimate?

Answer 12

The age of the universe - Big Bang happened about 14 billion years ago

Question 13

What is the ‘steady state’ theory?

Answer 13

The universe has always existed as it is now, nd it always will do. It’s based on the idea that the universe appears pretty much the same everywhere. This theory explains the apparent expansion by suggesting that matter is being created in the spaces as the universe expands.

Question 14

What is the main piece of evidence that doesn’t fit well with the steady state theory?

Answer 14

Cosmic Microwave Background Radiation (CMBR)

Question 15

There’s uniform [ ] from all directions

Answer 15

microwave radiation

Question 16

Scientists have detected [ ] coming from all parts of the universe

Answer 16

Low frequency electromagnetic radiation

Question 17

What is CMBR

Answer 17

Low frequency electromagnetic radiation coming from all parts of the universe

Question 18

Which is the only theory that can explain CMBR?

Answer 18

The Big Bang theory

Question 19

How does the Big Bang theory explain CMBR?

Answer 19

Just after the Big Bang while the universe was still extremely hot, everything in the universe emitted very high frequency radiation. As the universe expanded it has cooled, and this radiation has dropped in frequency and is now seen as microwave radiation

Question 20

What are the limitations of the Big Bang theory?

Answer 20

1) It suggests the universe should be slowing down the rate of expansion but it is actually expanding faster
2) Doesn’t explain what caused the explosion or what the conditions were like before the explosion