* Absolute Magnitude: This measures a star's intrinsic brightness, as if it were located 10 parsecs (32.6 light-years) away from Earth. A higher absolute magnitude means a dimmer star.

* Apparent Magnitude: This is the brightness we actually observe from Earth. It's affected by both a star's intrinsic brightness (absolute magnitude) and its distance from us.

The key here is distance. If a star is much farther away, even if it's intrinsically brighter, its light has to travel a much greater distance to reach us. This causes it to appear dimmer.

In your example: The star with a greater absolute magnitude than Sirius is intrinsically brighter. However, being 100 times farther away means its light is spread out over a much larger area, making it appear much dimmer in our sky compared to Sirius.

Let me know if you'd like more details about stellar magnitudes!