Question

Why do astronomers often say that large telescopes are like time machines, or equivalently, why is distant light old light?

Answer 1

⭐ $\underline{\boxed{\tt{\huge{\red{AnSwEr}}}}}$ ⭐

Hey❗, Nice Question Dear

✍ ️Let's understand the concept behind your question with an example.

✍ ️Light also takes time to travel, sunlight takes approx 8 min to reach earth surface ..

✍ ️Imagine that you are an scientist and observing sky with highly advance telescope and you find that , there is a planet 'A' which is 1000 light year away from Our Earth ..

✍ ️It means the light emitted by that plant A will reach Earth after travelling 1000 earth year. therefore the image observed by you in the telescope is the image of planet A of 1000 years back and not the latest one (as the light reflection of that planet on the telescope is the light which has travelled 1000 light year and not the light which is reflected by planet at that particular instant ). simply the image observed is of 1000 year old planet 'A'.

✍ ️It means you are watching the past of planet(1000years before one, instead of latest one).

✍️ Therefore Astronomer say that large telescope are like time machines ...

I hope it helps you dear...

❤️Be happy ❤️