The Origin of the Universe

Question 1

The universe seems to be ____

Answer 1

The universe seems to be EXPANDING

Question 2

How can we tell the universe is expanding?

Answer 2

All its galaxies seem to be moving away from each other

Question 3

What evidence do we have that galaxies are moving away from each other?

Answer 3

Red-shift

Question 4

Explain red-shift and how it provides evidence of the universe expanding

Answer 4

1. Different chemical elements ABSORB different FREQUENCIES of light
2. Each element produces a SPECIFIC PATTERN of DARK LINES at the frequencies that it ABSORBS in the visible spectrum
3. When we look at light from DISTANT galaxies we can see the SAME PATTERNS but at slightly LOWER frequencies than they should be - they’re shifted towards the RED END of the spectrum. This is called red-shift.
4. The lower frequencies are caused by the Doppler effect

Question 5

Describe the bit about frequencies of chemical elements in red-shift

Answer 5

1. Different chemical elements ABSORB different FREQUENCIES of light
2. Each element produces a SPECIFIC PATTERN of DARK LINES at the frequencies that it ABSORBS in the visible spectrum

Question 6

Explain the basic bit of red-shift

Answer 6

3. When we look at light from DISTANT galaxies we can see the SAME PATTERNS of light absorption but at slightly LOWER frequencies than they should be - they’re shifted towards the RED END of the spectrum. This is called red-shift.

Question 7

What happens to the waves emitted by an object when it is moving away from or towards you, compared to when it is stationary? (2)

Answer 7

The WAVELENGTHS and FREQUENCIES of the waves seem different

Question 8

What will the wavelength and frequency of a source moving TOWARDS you sound like compared to when it is stationary?

Answer 8

The frequency will seem HIGHER

Wavelength will seem SHORTER

Question 9

What will the wavelength and frequency of a source moving AWAY from you sound like compared to when it is stationary?

Answer 9

The frequency will seem LOWER

Wavelength will seem LONGER

Question 10

So to recap

Towards = ___ and ___

Away = ___ and ___

Answer 10

Towards = HIGHER and SHORTER (‘h’s)

Away = LOWER and LONGER (‘l’s)

Question 11

What is the phenomenon when the WAVELENGTHS and FREQUENCIES of the waves seem different when an object emitting waves is moving towards you and away from you called?

Answer 11

The Doppler effect

Question 12

What kind of wave/ waves does the Doppler effect happen to?

Answer 12

Longitudinal AND transverse

Question 13

What do measurements of the red-shift that ALL GALAXIES suggest? What does this provide evidence for?

Answer 13

That ALL galaxies are MOVING AWAY from us very quickly, and it’s the same result in EVERY DIRECTION you look in.

Evidence that the whole universe is expanding

Question 14

What’s the relationship between how far a galaxy is from us and how fast they are moving away from us?

Answer 14

The FURTHER a galaxy is from us the FASTER it is moving away

Question 15

Why does the universe’s apparent expansion (aka red-shift) provide evidence for the Big Bang theory?

Answer 15

Something had to have caused this expansion to start - which was probably a big explosion

Question 16

What is the ‘Big Bang theory’?

Answer 16

All the matter in the universe must have been compressed into a VERY SMALL SPACE. Then it exploded from that SINGULARITY and started expanding

Question 17

The expansion is ___ ____ .

Answer 17

The expansion is STILL ONGOING

Question 18

What can we use the universe’s current rate of expansion to do?

Answer 18

Estimate the universe’s age

Question 19

How long ago do we think the Big Bang happened?

Answer 19

14 billion years ago

Question 20

What does the ‘Steady State’ theory say?

Answer 20

That the universe has ALWAYS existed as it is NOW, and it ALWAYS WILL do.

Question 21

What is the ‘Steady State’ theory based on?

Answer 21

The idea that the universe appears pretty much the SAME EVERYWHERE

Question 22

How does the Steady State theory explain the apparent expansion of the universe?

Answer 22

By suggesting that matter is being CREATED in the spaces as the universe expands

Question 23

What is another piece of evidence for the Big Bang theory?

Answer 23

Cosmic microwave background radiation (CMBR) - the radiation that is found everywhere in the universe at pretty much the same frequency - what would have been released when the singularity exploded

Question 24

What can the Steady State theory not explain?

Answer 24

Cosmic microwave background radiation (CMBR)

Question 25

Which is the only theory that can explain CMBR?

Answer 25

The Big Bang theory

Question 26

There’s ____ microwave radiation from ____ ____ .

Answer 26

There’s UNIFORM microwave radiation from ALL DIRECTIONS .

Question 27

What is cosmic microwave background radiation (CMBR)?

Answer 27

Low frequency electromagnetic radiation that has been detected coming from ALL PARTS of the universe

Question 28

Explain where CMBR came from

Answer 28

Just after the Big Bang when 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 had dropped in frequency and is now seen as MICROWAVE RADIATION

Question 29

What are the 2 main reasons some astronomers believe in the Steady State theory?

Answer 29

1. Say EVIDENCE just points that way

2. Don’t want to change their minds - would mean admitting they were WRONG in the first place

Question 30

What can the Big Bang not explain?

Answer 30

1. The Big Bang theory predicts that the universe;s expansion should be SLOWING DOWN - but as far as we can tell it’s actually SPEEDING UP
2. What CAUSED the explosion
3. What the CONDITIONS were like before the explosion (or if there was a ‘before’)

Question 31

What is the most probable future of the Big Bang theory? Why?

Answer 31

It will be adapted for its weaknesses NOT dumped - it explains so much so well