Scientific theories can never be proved true beyond all doubt.
Indicate whether the statement is true or false
Question 2
What is a standard candle?
A) an object for which we are likely to know the true luminosity
B) an object for which we can easily measure the apparent brightness
C) a class of objects in astronomy that all have exactly the same luminosity
D) any star for which we know the exact apparent brightness
E) a long, tapered candle that lights easily