Here's why:

* Distance: Regulus is approximately 77 light-years away from Earth.

* Light Travel Time: Light travels at a finite speed (approximately 299,792,458 meters per second).

* Observation: When we look at Regulus, we are seeing the light that left the star 77 years ago, the time it took for that light to reach our eyes.

So, the light you see from Regulus today is a snapshot of the star as it was 77 years ago.