What is a standard candle?
A standard candle is an astronomical object that has a known absolute magnitude (intrinsic brightness). They are extremely important to astronomers since by measuring the apparent magnitude of the object the distance to the source can be determined by using the inverse square law. Examples of such objects are Cepheid variable stars, whose absolute magnitude is proportional to their period of variability and also the Type-1a supernovae, since it is believed that they all have essentially the same peak absolute magnitude.
AS
Related Physics A Level answers
All answers ▸Define a "Vector Quantity" and list 2 examples.
There is a point between the Moon and the Earth where the gravitational attractions are equal and opposite. How much further is this point from the Earth than the Moon
What is gravitational potential energy? Why is it negative?
Electrons moving in a beam have the same de Broglie wavelength as protons moving in a separate beam. The proton beam moves at a speed of 3.1 x 10^4 m/s. What is the speed of the electrons?