# Time dilation and the age of the universe **URL:** \ **Category:** Factual Questions\ **Created:** [September 13, 2009, 3:22am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884 "2009-09-13T03:22:25Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Malleus\_Incus\_Stapes](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/malleus_incus_stapes/32/3293_2.png) [@Malleus\_Incus\_Stapes](https://boards.straightdope.com/u/Malleus_Incus_Stapes)\ **Post date:** [September 13, 2009, 3:22am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/1 "2009-09-13T03:22:25Z")
Scientists tell us that the world is about fifteen billion years old, give or take. But Einsteinian relativity says the passage of time is dependent on the local gravitational force. So presumably it would be more accurate to say, “On Earth-time the universe is 15 bil”. How old would the world be from the perspective of someone in the empty vacuum of space? What if you had someone (something?) whose consciousness filled the whole universe, and had been there since the Big Bang? How old would the world be to such an entity? ---
**Author:** ![snailboy](https://avatars.discourse-cdn.com/v4/letter/s/97f17d/32.png) [@snailboy](https://boards.straightdope.com/u/snailboy)\ **Post date:** [September 13, 2009, 4:23am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/2 "2009-09-13T04:23:24Z")
The age of the universe was measured with telescopes orbiting Earth where there is less gravity. Even if they were sitting on Earth, the effects are pretty negligible. Using the formulas on Wikipedia, I calculated that if we perceived the universe to be exactly 15 billion years old from the surface of Earth, then in deep space it would be perceived as 15,000,021,190 years old. I imagine this is within the expected deviation of their calculations. ---
**Author:** ![WoodenTaco](https://avatars.discourse-cdn.com/v4/letter/w/45deac/32.png) [@WoodenTaco](https://boards.straightdope.com/u/WoodenTaco)\ **Post date:** [September 13, 2009, 5:13am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/3 "2009-09-13T05:13:17Z")
> [@Malleus\_Incus\_Stapes](#): > > But Einsteinian relativity says the passage of time is dependent on the local gravitational force. No, relativity says the passage of time is dependent on relative velocities. Gravity can _cause_ velocity, but it’s an important difference. As to the more fundamental question of how our velocity affects our calculations of the age of the universe, I am not really qualified to answer. ---
**Author:** ![OldGuy](https://avatars.discourse-cdn.com/v4/letter/o/3bc359/32.png) [@OldGuy](https://boards.straightdope.com/u/OldGuy)\ **Post date:** [September 13, 2009, 5:21am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/4 "2009-09-13T05:21:15Z")
> [@WoodenTaco](#): > > No, relativity says the passage of time is dependent on relative velocities. Gravity can _cause_ velocity, but it’s an important difference. As to the more fundamental question of how our velocity affects our calculations of the age of the universe, I am not really qualified to answer. No the OP is correct, according to GENERAL relativity, the passage of time depends on the strength of the gravitational field. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [September 13, 2009, 7:27am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/5 "2009-09-13T07:27:50Z")
The age of the universe is known more exactly than you think. The universe is 13,730,000,000 years old, with an uncertainty of plus or minus 120,000,000 years: > **[Age of the universe](https://en.wikipedia.org/wiki/Age_of_the_universe)** > > In physical cosmology, the age of the universe is the time elapsed since the Big Bang. Astronomers have derived two different measurements of the age of the universe: a measurement based on direct observations of an early state of the universe, which indicate an age of 13.787±0.020 billion years as interpreted with the Lambda-CDM concordance model as of 2021; and a measurement based on the observations of the local, modern universe, which suggest a younger age. The uncertainty of t In the 18th... So the age is known to within one percent. I’ll let someone else explain this, but time dilation has nothing to do with it. The age of the universe can be calculated without regard to the gravity, the speed, or the amount of air on the Earth (or whatever you mean by recalculating it in “the empty vacuum of space.” ---
**Author:** ![Don\_t\_Panic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/don_t_panic/32/398_2.png) [@Don\_t\_Panic](https://boards.straightdope.com/u/Don_t_Panic)\ **Post date:** [September 13, 2009, 9:55am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/6 "2009-09-13T09:55:21Z")
> [@Wendell\_Wagner](#): > > The age of the universe is known more exactly than you think. Which caused [Simon Singh to fall out with Katie Melua](http://www.guardian.co.uk/education/2005/sep/30/highereducation.uk). ---
**Author:** ![Polerius](https://avatars.discourse-cdn.com/v4/letter/p/d78d45/32.png) [@Polerius](https://boards.straightdope.com/u/Polerius)\ **Post date:** [September 13, 2009, 10:06am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/7 "2009-09-13T10:06:55Z")
> [@Wendell\_Wagner](#): > > The age of the universe is known more exactly than you think. The universe is 13,730,000,000 years old, with an uncertainty of plus or minus 120,000,000 years: In whose timeframe? Assume that after the Big Bang two particles were created. One was speeding near c, and the other was going slower. According to the first particle, not much time has passed since the Big Bang. According to the second particle, a few billion years have passed. Which one of the two particles is correct as to the age of the Universe? In fact, if a photon was created during the Big Bang and has been travelling ever since, according to that photon, no time has elapsed since the Big Bang. It has just happened. So the speed of an observer changes what they perceive to be the age of the Universe. What’s wrong in the statements above? ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [September 13, 2009, 11:00am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/8 "2009-09-13T11:00:51Z")
As I said, I’ll let someone else explain why time dilation has nothing to do with this value, since I don’t understand it well enough. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [September 13, 2009, 11:52am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/9 "2009-09-13T11:52:48Z")
I maybe wrong, but isnt it just semantics? I have a boat. I measure it with one ruler. Its 25 feet long. I now use a warped ruler. It now measures 25.3 feet long. Depending on what you use to measure the boat, you get different numbers. But the real PHYSICAL length of the boat hasnt changed one iota. Seems to me that same concept applies to the real age of the universe. ---
**Author:** ![The\_Seventh\_Deadly\_Finn](https://avatars.discourse-cdn.com/v4/letter/t/6bbea6/32.png) [@The\_Seventh\_Deadly\_Finn](https://boards.straightdope.com/u/The_Seventh_Deadly_Finn)\ **Post date:** [September 13, 2009, 12:23pm UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/10 "2009-09-13T12:23:02Z")
There’s no such thing as objective time, it’s just an illusion created by the fact that entropy was freakishly low in the past. I realize that’s no help, but I actually do believe it. ---
**Author:** ![david\_42](https://avatars.discourse-cdn.com/v4/letter/d/cc9497/32.png) [@david\_42](https://boards.straightdope.com/u/david_42)\ **Post date:** [September 13, 2009, 1:34pm UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/11 "2009-09-13T13:34:54Z")
If you are moving, your perception of time changes, but time in the frame does not. You can always determine your speed and therefor the correct passage of time for the frame. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [September 13, 2009, 4:09pm UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/12 "2009-09-13T16:09:55Z")
> [@Polerius](#): > > In whose timeframe? Presumably WRT the [comoving frame](http://en.wikipedia.org/wiki/Comoving_distance). Essentially, the frame where the galaxies are all more-or-less unmoving (although they still have small relative motions). I suspect they also assume “not deep in a gravity well”. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 13, 2009, 7:34pm UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/13 "2009-09-13T19:34:49Z")
The Earth’s gravity well is really, really shallow, shallow enough that even with the “precise” value of 13.7 billion years, it’s not enough to make a difference. ---
**Author:** ![Malleus\_Incus\_Stapes](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/malleus_incus_stapes/32/3293_2.png) [@Malleus\_Incus\_Stapes](https://boards.straightdope.com/u/Malleus_Incus_Stapes)\ **Post date:** [September 13, 2009, 8:03pm UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/14 "2009-09-13T20:03:34Z")
Ah, thanks. That clears up one long-standing mystery. ---
**Author:** ![Tom\_Tildrum](https://avatars.discourse-cdn.com/v4/letter/t/e95f7d/32.png) [@Tom\_Tildrum](https://boards.straightdope.com/u/Tom_Tildrum)\ **Post date:** [September 14, 2009, 3:25am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/15 "2009-09-14T03:25:12Z")
> [@Wendell\_Wagner](#): > > The age of the universe is known more exactly than you think. The universe is 13,730,000,000 years old, with an uncertainty of plus or minus 120,000,000 years: Reminds me of the time I asked the museum guard how old the dinosaur skeleton was, and he replied, “65,000,013 years old.” I asked him how they were able to date it with such precision, and he said, “I don’t know, but I started working here 13 years ago, and back then they told me it was 65,000,000 years old.” ---
**Author:** ![Claude\_Remains](https://avatars.discourse-cdn.com/v4/letter/c/898d66/32.png) [@Claude\_Remains](https://boards.straightdope.com/u/Claude_Remains)\ **Post date:** [September 14, 2009, 6:26am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/16 "2009-09-14T06:26:40Z")
> [@snailboy](#): > > The age of the universe was measured with telescopes orbiting Earth where there is less gravity. Nitpick. While the Hubble space telescope has been in service for many years, the first math was laid down by Edwin Hubble himself in 1929. Hense the Hubble constant. ---
**Author:** ![Claude\_Remains](https://avatars.discourse-cdn.com/v4/letter/c/898d66/32.png) [@Claude\_Remains](https://boards.straightdope.com/u/Claude_Remains)\ **Post date:** [September 14, 2009, 6:33am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/17 "2009-09-14T06:33:01Z")
> [@Tom\_Tildrum](#): > > Reminds me of the time I asked the museum guard how old the dinosaur skeleton was, and he replied, “65,000,013 years old.” I asked him how they were able to date it with such precision, and he said, “I don’t know, but I started working here 13 years ago, and back then they told me it was 65,000,000 years old.” 😃 I’m gonna use this with your permission. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [September 14, 2009, 9:58am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/18 "2009-09-14T09:58:27Z")
While it’s true that the first estimates of the age of the universe were made long before the Hubble space telescope existed, the more recent exact measurements of its age were made using observations from that telescope. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [September 14, 2009, 10:18am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/19 "2009-09-14T10:18:18Z")
Does not the 3K radiation that permeates all space come into play when trying to determine an absolute reference frame? It said it did in a book I got in sixth grade… ---
**Author:** ![Tom\_Tildrum](https://avatars.discourse-cdn.com/v4/letter/t/e95f7d/32.png) [@Tom\_Tildrum](https://boards.straightdope.com/u/Tom_Tildrum)\ **Post date:** [September 14, 2009, 10:57am UTC](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884/20 "2009-09-14T10:57:48Z")
> [@Claude\_Remains](#): > > 😃 I’m gonna use this with your permission. Please feel free. I stole it from Reader’s Digest, after all. [Next page](https://boards.straightdope.com/t/time-dilation-and-the-age-of-the-universe/509884.md?page=2)