When I look at the night sky, I often view the stars not just in space but also in terms of their places in time. Light moves at a finite speed (299,792 kilometers per second, to be precise), so the journey from star to star is a very long one even for a beam of light. When astronomers talk about light years of distance, they are literally describing the number of years it takes for light to travel from those distant stars to your eyeball.
And so when I heard about the death of Stephen Hawking, I couldn’t help thinking about his place in the stars. At some distance from Earth, there is a star whose light (as seen right now on Earth) started its journey at the time when you were born. You can think of that as your birth star. We all have one. Hawking has one–and you can easily see it. His birth star is shining brightly in the evening tonight.
