Tukuk-OSA light-year is a distance, not a time — about 9.5 trillion kilometres. When you see Orion, its nearest bright stars are around 250 light-years off, so the pattern left your retina’s data centuries ago in the sense that its information is centuries old. Nothing in the night sky is “now”: the only truly present object overhead is the Moon, 1.3 light-seconds away. Looking farther is literally looking back in time, which is why telescopes are the closest thing to a time machine astronomy owns.
Stars are thermonuclear engines fusing hydrogen into helium, and their mass sets their lifespan: small red dwarfs burn for trillions of years; the Sun, mid-sized, gets about 10 billion in total and is just over halfway; huge blue stars are spent in a few million. When stars like the Sun exhaust fuel they shed their outer layers and leave a white dwarf — Earth-sized, teaspoon-heavy. The giants explode as supernovae, and inside those explosions (and inside the stars before them) elements heavier than helium are forged. The calcium in your bones, the iron in your blood — astronomically speaking, all of it is recycled star exhaust.
Betelgeuse, the red supergiant in Orion, is the famous “might explode any time” star — “any time” meaning within the next hundred thousand years or so, and possibly already decades past if it has, its light still arriving. When it finally does, it will not harm Earth (about 500–700 light-years away) but will briefly shine as bright as Venus in daylight.