Main Sequence Characteristics
Convert Hydrogen to Helium in core
Constant Luminosity
Trig Parallax
View Position 6 Months apart
Measure change in angle
Divide by 2
Use trig and known distance
Massive Stars have Greater Luminosity
Greater gravitational forces
Higher temp and denser core
Greater rate of fusion
Greater temperature
Greater power output
Moving away vs towards
Away: Lower frequency and higher wavelength
Towards: Higher frequency and lower wavelength
Doppler Shift
Measure wavelength emmitted
Compare with known lab wavelength
Work out value for Z
Hubble supports expanding universe
Change in wavelength is greater for further away galaxies
Move faster the further away they are so move away from each other
Scattered data due to limited standard candles
Not reliable because no certain value for hubbles constant, big range and uncertainty
Earth Sun Distance
1.5 x 10^11
Last changed10 months ago