Fusion in giant stars takes us all the way to iron before a Type ...

[RYAN BANYAN]

Fusion in giant stars takes us all the way to iron before a Type II supernova occurs. Why did it stop with helium in the far more energetic Big Bang?
 
  What will be an ideal response?

Question 2

Quasars are far more luminous than Type I supernovae; why not use them to calibrate Ho and the age of the universe?
 
  What will be an ideal response?

[polinasid]

Answer to Question 1

The expansion of the Big Bang cooled the temperature to below 100 million K by the time the helium abundances could have allowed carbon production to start.

Answer to Question 2

Quasars vary over a period of weeks in brightness, and vary a great deal in luminosity from object to object. We need a uniform, consistent standard candle, and the run-away detonation of a 1.4 solar mass white dwarf in a Type I supernova gives us just the desired combination of luminosity and consistency.

[RYAN BANYAN]

Both answers were spot on, thank you once again

[polinasid]

Great! Please up vote