—Doug Bloom, North Branch, Minnesota First, the stars we can see with the unaided eye are much closer—less than about 1,000 light-years away. Still, because stars are so extremely long-lived, it is almost certain that the vast majority of them, including the distant ones that require a telescope to view, are still twinkling away. But it’s quite true that even if the brightest star in the sky (Sirius, which is relatively close at 8.6 light-years away) were to disappear tomorrow, we wouldn’t know about it for nearly a decade.

Might Many of the Stars We See in the Night Sky No Longer Exist  - 69