0

In the following sentence I want to understand the meaning of the bolded part:

The light from most stars takes millions of years to reach us, so not only the present existence of these stars debatable, but so are the very concepts of the "present" and "existence".

What does it mean?

  • What exactly is it that's unclear to you? Which part of the sentence do you not understand? – Janus Bahs Jacquet Apr 17 '14 at 7:18
  • The proverb 'seeing is believing' means 'If I can see it, it's real / there / happening ... now.' It's taken as axiomatic. However, cosmological concepts can even challenge what we consider axioms, fundamentals. Is time really linear? Has the speed of light always been as it is now? Could light-information have been fed into the system, rather than needing to have originated from the apparent source ('distant galaxy')? – Edwin Ashworth Apr 17 '14 at 8:14
  • Actually the light from most visible stars only takes a few hundred years to reach Earth. There is a huge star, S Doradus, in the Large Magellanic Cloud Clouds that almost makes it to visibility and is 169,000 light years away. – Oldcat Apr 17 '14 at 21:10
3

It refers to the fact that stars have been existing for millions of years, and their light takes millions of years to reach us, to be visible to us. So, when we see theirs light, are the stars form which the light is sent still in existence? If not, can we say that they still exist because we see their light at present?

0

The light from most stars takes millions of years to reach us, so not only the present existence of these stars debatable, but so are the very concepts of the "present" and "existence".

Einstein's Special Relativity showed that anything that is far away in space is also distant in time. That is counterintuitive, but it seems to have held up in experiments. So the idea of "the present" meaning "at this same moment" now only works for something that is also "present" in the other sense, meaning "here."

I also so not understand how the concept of existence is made debatable by the distance and by relativity. Maybe the author claimed a little too much?

  • I see lighting before I hear thunder. Oh Noes! – Oldcat Apr 17 '14 at 21:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.