When you look up at the night sky, some stars shine brightly while others are barely visible. But does a bright star appear that way because it is extremely luminous, or simply because it is close to Earth?

To distinguish between how bright a star appears and how bright it actually is, astronomers use two distinct scales: apparent magnitude (m) and absolute magnitude (M). Based on a logarithmic system created by the ancient Greek astronomer Hipparchus and refined by modern astrophysics, a difference of 5 magnitudes corresponds to a factor of 100 in brightness—where smaller or negative numbers represent brighter celestial objects.

Watch the video to explore the inverse-square law of light, how to convert between apparent and absolute magnitude, and how calculating a star's distance modulus (m - M) reveals its true place in cosmic space