0
$\begingroup$

Okay, So, this thought experiment starts with the movie, Interstellar. In which humans went through a wormhole to a system consisting of a Black Hole. They landed on a planet (I don't remember its name) with an hour equivalent to 7 earth years. Now, here is my question: - Suppose, a scientist on that planet measures the age of the universe. Then what would be the age measured by him? Would it be 13.8 billion years or something else?

Note: - The scientist is completely unaware of the age of unvierse measured from earth.

Improve this question
$\endgroup$
2
  • $\begingroup$ When does he measure it? $\endgroup$
    – WillO
    Commented Sep 23, 2019 at 13:58
  • $\begingroup$ Right now, i.e. when this question is posted. $\endgroup$
    – DHRUV PATEL
    Commented Sep 26, 2019 at 16:23

1 Answer 1

Reset to default
2
$\begingroup$

The observer is subject to gravitational time dilation by a factor of about 61320. They will see a blue-shifted universe, with all the wavelengths shifted by this factor looking much younger than we see it (they will still see galaxies etc, which seem to have developed fairly fast). When they do their cosmological observations and model the past expansion of the universe they end up with an age of about 224,559 years! Except that those years are planet-years. Translate it to years as measured in non-dilated flat space and you get 13.8 billion years. It is the same universe, just different time yardsticks.

Improve this answer
$\endgroup$
3
  • $\begingroup$ How did you calculate this exact figure of age and time dilation factor of about 224559years and 61320 respectively? $\endgroup$
    – DHRUV PATEL
    Commented Sep 24, 2019 at 6:52
  • $\begingroup$ @DHRUVPATEL - If 1 hour is 7 years, the ratio of time flow is (years)*(days/year)*(hours/day)=7*365*24 = 61320. And 13.77 billion flat-space years/61320 is about 224,559 planet-years. $\endgroup$
    – Anders Sandberg
    Commented Sep 25, 2019 at 10:52
  • $\begingroup$ Thanks for making it clear. $\endgroup$
    – DHRUV PATEL
    Commented Sep 26, 2019 at 16:22

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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