P7 | astronomy

Question 1

what is the steady state theory?

Answer 1

• the universe has always existed
• the universe is the same everywhere
• there is no beginning or end to the universe
• the universe is constantly expanding and new mass is being created
• density of the universe has always been the same

Question 2

what is the big bang theory?

Answer 2

• initially, the matter of the universe occupied a very small space
• this small space was very dense and hot which led to an explosion
• the universe started expanding and is still constantly expanding
• the universe has a finite age of 13.8 billion years

Question 3

how does redshift support both the big bang and steady state theory?

Answer 3

• suggests the universe is expanding
• galaxies moving further away from us appear on the red end of the EM spectrum
• further galaxies appear more red than closer ones which supports the idea that the universe is constantly expanding

Question 4

how does CMB radiation support the big bang theory?

Answer 4

• scientists have detected low frequency microwave radiation in all parts of the universe
• this radiation is the leftover energy from the initial big bang explosion
• this supports the idea that the universe had a beginning

Question 5

what is redshift?

Answer 5

• a phenomenon where EM radiation (e.g. light) from an object increases in wavelength as objects move apart
• light from other stars/galaxies shifts towards the red end of the spectrum as they move further away from us as the light is taking longer to reach us