our dynamic universe pt.2

Question 1

the doppler effect

Answer 1

causes shifts in wavelengths of sound and light

Question 2

redshift

Answer 2

light from objects moving away from us is shifted to longer wavelengths

Question 3

redshift of a galaxy

Answer 3

the change in wavelength divided by the emitted wavelength, for slow moving galaxies, redshift is the ratio of the recessional velocity of the galaxy to the velocity of light

Question 4

G

Answer 4

gravitational constant (6.67x10^-11Nm^2kg^-2)

Question 5

plus or minus in the doppler effect

Answer 5

+ if it’s moving away, - if it’s moving towards

Question 6

fo

Answer 6

observed frequency

Question 7

fs

Answer 7

stationary frequency

Question 8

v and vs

Answer 8

speed of sound and speed of the source

Question 9

speed of sound

Answer 9

340m/s

Question 10

red shift ratio

Answer 10

the ratio of change in wavelength to the rest wavelength, always between 0 and 1 with no units

Question 11

what is the red shift ratio used for

Answer 11

to determine the velocity that a star is moving away from us

Question 12

recessional velocity

Answer 12

the velocity that a star is moving away from us

Question 13

the hubble constant graph

Answer 13

a straight line with gradient 1 with recessional velocity on the y axis and direction on the x axis

Question 14

hubbles constant

Answer 14

2.3x10^-18

Question 15

newtons inverse square law of gravitation

Answer 15

there is a force of attraction between any two objects in the universe

Question 16

F=(Gm1m2)/r^2

Answer 16

m1 and m2 are the masses of the two objects, and r is the distance between them

Question 17

proof of the big bang theory

Answer 17

cosmic microwave background radiation, abundance of H and He

Question 18

if the scale is increased

Answer 18

the percentage uncertainty is less

Question 19

more distant galaxies are

Answer 19

moving away at a greater velocity

Question 20

how does redshift support the big bang theory

Answer 20

redshift is evidence the universe is expanding, expanding universe supports the big bang theory

Question 21

length contraction

Answer 21

the decrease in length of an object moving relative to an observer

Question 22

the orbital speed of the sun and other stars gives us

Answer 22

a way of determining the mass of our galaxy