Question

1. why do some stars appear brighter than others when we look at the night sky?

Explanation:

The brightness of stars as seen from Earth depends on two main factors: their actual luminosity (how much energy they emit) and their distance from us. Stars with higher actual luminosities and closer distances appear brighter. Also, atmospheric conditions can affect the apparent brightness we observe.

Answer:

Some stars appear brighter than others when we look at the night - sky because of differences in their actual luminosities, their distances from Earth, and atmospheric effects.