Which term is used for the brightness of a star as seen from Earth?

Which term is used for the brightness of a star as seen from Earth?

• A. Absolute brightness
• B. Apparent magnitude
• C. Light year
• D. Astronomical Unit (AU)

Answer: (B)

Brightness of a star as seen from Earth is described by apparent magnitude. This scale measures how bright the star appears in our sky, not how much light it actually emits. Smaller numbers mean brighter appearances, and very bright stars can even have negative magnitudes. This differs from absolute brightness, which is the star’s intrinsic luminosity at a standard distance of 10 parsecs. The terms light year and Astronomical Unit are distance measures—light year is how far light travels in a year, and AU is the average Earth–Sun distance. So the term that captures how bright a star looks from Earth is apparent magnitude.

Brightness of a star as seen from Earth is described by apparent magnitude. This scale measures how bright the star appears in our sky, not how much light it actually emits. Smaller numbers mean brighter appearances, and very bright stars can even have negative magnitudes. This differs from absolute brightness, which is the star’s intrinsic luminosity at a standard distance of 10 parsecs. The terms light year and Astronomical Unit are distance measures—light year is how far light travels in a year, and AU is the average Earth–Sun distance. So the term that captures how bright a star looks from Earth is apparent magnitude.