Question

Daniel observed and compared some stars at night and recorded his observations in a chart.

A 2 column table with 3 rows labeled star observations. The first column is labeled star with entries X, Y, Z. The second column is labeled observation with entries brightest, least bright, somewhat bright.
Daniel later discovered that star X is farther away from Earth than the other stars he observed, and star Z is closest to Earth.

Which conclusion is best supported by Daniel’s observations and discoveries?

Star X is more luminous than both stars Y and Z.
Star X is more luminous than star Z, but not star Y.
Star Y is more luminous than star X.
Star Z is more luminous than star Y.

Answer 1

Star X is more luminous than both stars Y and Z.

Reason: Apparent brightness depends on both luminosity and distance (inverse-square law). X appears brightest even though it is farthest away, so it must have the greatest intrinsic luminosity. Z is closest but not the brightest, so it is less luminous than X; Y is the least bright, so it is not more luminous than X.