Why Starlight Is a Picture of the Past
Why Starlight Is a Picture of the Past — After learning that starlight comes from the past, I came to weigh again the feeling of longing. When we call someone to mind, what we see is never the person as they are now, but as they once were. When we draw in our hearts the face of one who left before us, we are seeing that person starlight. The light has already departed, yet it still reaches within me and shines. Perhaps love is the keeping of vanished light for a long, long time. If a star has set but its light remains in someone night sky, that star has not wholly vanished. And we, too, will live on as light remaining in someone sky.
To see a star in the night sky is, we assume, to see the star where it is now. Yet some stars are so far that their light takes thousands, even tens of thousands of years to reach our eyes. Then the starlight we see now — from when is that picture? Could the star already have vanished long ago, while only its light is still on the journey?
For long, people believed light reached everywhere the instant it was lit — so fast as to have no limit. In the 17th century, the Danish astronomer Romer, watching the times when Jupiter moon slipped into shadow, noticed something odd. When Earth drew farther from Jupiter, the moon appeared later than scheduled. Light needed more time to cross the lengthened distance. He realized: light, too, has a speed. However fast, light was in the end a traveler that spends time to cross space.
Light travels about 300,000 kilometers per second. A speed beyond imagining, yet before cosmic distances even that is slow. Sunlight runs eight minutes to reach us, so the sun we see is the sun of eight minutes ago. The nearest star light travels four years; some stars shine in our eyes now by light that set out tens of thousands of years past. What we see in the night sky is not the stars present but a vast museum of time, where each star different past is gathered in one place. Some of those stars have truly already vanished. We are seeing the once-living light of dead stars.
- GPS satellites calculate this speed of light at every turn to tell us our location. Leave out the fact that light spends time to travel, and the navigator soon loses its way.
- For astronomers to view the distant universe is to view the universe old form. The farther they look, the older the past they see. A telescope is a kind of time machine.
- On a video call, the faint lag with someone on the other side of the earth comes from the time light (radio waves) needs to cross that great distance. Light finiteness seeps even into daily life.
往은 이미 지나가 버린 옛것을 뜻하니, 떠나온 지 오래인 과거의 빛을 지금 보는 별빛의 성질과 통한다.
Meet this hanja in Cheonjamun →After learning that starlight comes from the past, I came to weigh again the feeling of longing. When we call someone to mind, what we see is never the person as they are now, but as they once were. When we draw in our hearts the face of one who left before us, we are seeing that person starlight. The light has already departed, yet it still reaches within me and shines. Perhaps love is the keeping of vanished light for a long, long time. If a star has set but its light remains in someone night sky, that star has not wholly vanished. And we, too, will live on as light remaining in someone sky.
