Our expanding universe

Question 1

What is the Doppler effect

Answer 1

The apparent change in the frequency of a wave caused by relative motion between the source and the observer

Question 2

What is the speed of sound

Answer 2

340ms-1

Question 3

When the sound is moving closer use

Answer 3

-

Question 4

When the sound is moving away use

Answer 4

+

Question 5

What does redshift mean

Answer 5

The wavelength of the light is stretched so the light is seen as shifted towards the red part of the spectrum

Question 6

Name the evidence for the Big Bang

Answer 6

1. Cosmic microwave background
2. Hydrogen and Helium abundance
3. Redshift
4. Hubbles law
5. Oblers paradox

Question 7

what is dark energy

Answer 7

a type of energy proposed to account for the missing energy in the universe; this is to account for the fact that the rate of expansion of the universe is increasing.

Question 8

what is dark matter

Answer 8

a type of matter proposed to account for the missing mass of the universe

Question 9

what is Cosmic microwave background radiation

Answer 9

the observed background radiation that is present in every direction in the universe.

Question 10

when a spectrum of light is examined it is found that the hotter the star, the _______ the peak wavelength of light that is emitted

Answer 10

shorter

Question 11

what is a blackbody radiator

Answer 11

an object that only radiates energy depending on its temperature e.g. stars and black metals

Question 12

What is the recessional velocity

Answer 12

The rate at which the object becomes more distant from the observer

Question 13

How old is the universe

Answer 13

13.8 bn years old