our dynamic universe pt.2 Flashcards
the doppler effect
causes shifts in wavelengths of sound and light
redshift
light from objects moving away from us is shifted to longer wavelengths
redshift of a galaxy
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
G
gravitational constant (6.67x10^-11Nm^2kg^-2)
plus or minus in the doppler effect
+ if it’s moving away, - if it’s moving towards
fo
observed frequency
fs
stationary frequency
v and vs
speed of sound and speed of the source
speed of sound
340m/s
red shift ratio
the ratio of change in wavelength to the rest wavelength, always between 0 and 1 with no units
what is the red shift ratio used for
to determine the velocity that a star is moving away from us
recessional velocity
the velocity that a star is moving away from us
the hubble constant graph
a straight line with gradient 1 with recessional velocity on the y axis and direction on the x axis
hubbles constant
2.3x10^-18
newtons inverse square law of gravitation
there is a force of attraction between any two objects in the universe
F=(Gm1m2)/r^2
m1 and m2 are the masses of the two objects, and r is the distance between them
proof of the big bang theory
cosmic microwave background radiation, abundance of H and He
if the scale is increased
the percentage uncertainty is less
more distant galaxies are
moving away at a greater velocity
how does redshift support the big bang theory
redshift is evidence the universe is expanding, expanding universe supports the big bang theory
length contraction
the decrease in length of an object moving relative to an observer
the orbital speed of the sun and other stars gives us
a way of determining the mass of our galaxy
