I don’t really understand it, could someone explain in basic terms?
Are we saying if a star is 120 million lightyears away, light from the star would take 120 million years to reach us? Meaning from the pov of time on earth, the light left the star when the earth was still in its Cretaceous period?
In: 292
What you said is 99% right. Any time someone is having a hard time with light years I make this analogy. If someone asked you how far the next city is from your house you might say “3 hours” as in 3 hours by car on the highway. So “3 car hours” is in fact a measure of distance. It takes a car 3 hours to go that far, but something faster or slower would take less or more time to go the same distance.
Continuing this analogy, if you took a picture of a hole your dog was digging when you left, when you got to the next city and showed it to a friend, they would be seeing the hole as it was 3 hours ago, not now. That is how light mostly works.
The 1% is barely worth mentioning. Due to inflation, the distance between distant objects increases as the light travels here. So the object is farther away than when the light first set out, and it took longer to get here than the distance when the light first started it’s journey would have been in a static universe. But this really just complicates things and is barely worth mentioning as it doesn’t change the fundamental understanding of the speed of light.
Latest Answers