Questions regarding electromagnetic radiation in the visible spectrum.

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12
votes
4answers
594 views

Is the light we see from stars extremely old?

Our nearest star Proxima Centauri is 4.243 light years away from Earth. Does that mean we are seeing light that is 4.243 years old everyday?
16
votes
3answers
329 views

Why can't light escape from a black hole?

I've heard that light can't escape from a black hole. Can it? If not, why?
4
votes
2answers
107 views

How does light affect the universe?

When light is emitted by for example a star, that star loses energy - which causes it to reduce its gravity. Then that energy begins a journey for potentially billions of years, until it reaches some ...