the brightness of a star depends on how much light is released by the star and how far the star is from earth

Answer 1

That is correct. The brightness, or apparent magnitude, of a star is determined by two primary factors: the amount of light it emits, also known as its intrinsic brightness or luminosity, and its distance from Earth.

The intrinsic brightness of a star refers to the total amount of energy it releases per unit of time. This can vary significantly among stars, depending on their size, temperature, and stage of evolution. Stars with greater luminosity emit more light and appear brighter to us.

However, even if a star is very luminous, its brightness as perceived from Earth will be reduced if it is located at a great distance. This is because light intensity diminishes with distance, following the inverse-square law. So, a star that is closer to Earth will appear brighter than a star of the same intrinsic brightness that is farther away.

To quantify the brightness of stars, astronomers use the magnitude scale. The apparent magnitude is a numerical value that represents a star's brightness as observed from Earth. The lower the magnitude value, the brighter the star appears. Very bright stars have negative magnitudes, while fainter stars have positive magnitudes.

It is important to note that the brightness we perceive can also be affected by factors like interstellar dust, which can scatter or absorb light as it travels through space. Thus, the observed brightness may not always perfectly reflect the intrinsic brightness and distance of a star.