# Astronauts and passage of time **URL:** \ **Category:** Factual Questions\ **Created:** [December 9, 2012, 3:06am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481 "2012-12-09T03:06:32Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![etv78](https://avatars.discourse-cdn.com/v4/letter/e/d78d45/32.png) [@etv78](https://boards.straightdope.com/u/etv78)\ **Post date:** [December 9, 2012, 3:06am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/1 "2012-12-09T03:06:32Z")
Do astronauts feel the pass of time while in orbit? ---
**Author:** ![BMalion](https://avatars.discourse-cdn.com/v4/letter/b/e274bd/32.png) [@BMalion](https://boards.straightdope.com/u/BMalion)\ **Post date:** [December 9, 2012, 3:08am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/2 "2012-12-09T03:08:10Z")
Why wouldn’t they? ---
**Author:** ![etv78](https://avatars.discourse-cdn.com/v4/letter/e/d78d45/32.png) [@etv78](https://boards.straightdope.com/u/etv78)\ **Post date:** [December 9, 2012, 3:16am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/3 "2012-12-09T03:16:37Z")
> [@BMalion](#): > > Why wouldn’t they? My thought: They aren’t seeing a sunrise/sunset, and that would be disorienting. ( **This** is why I stay out of GQ) ---
**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:** [December 9, 2012, 3:27am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/4 "2012-12-09T03:27:07Z")
Well, of course they’re disoriented (though the lack of gravity would be a much bigger effect). But there’s no reason they wouldn’t experience time. I mean, heck, even on Earth, there are plenty of contexts where a person might not see the Sun’s cycle (working late in a windowless office, say). ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [December 9, 2012, 3:44am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/5 "2012-12-09T03:44:49Z")
Even people in total sensory deprivation experience time. Why wouldn’t astronauts? Or do you mean they experience time, but have difficulty measuring its passage? ---
**Author:** ![BMalion](https://avatars.discourse-cdn.com/v4/letter/b/e274bd/32.png) [@BMalion](https://boards.straightdope.com/u/BMalion)\ **Post date:** [December 9, 2012, 4:19am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/6 "2012-12-09T04:19:09Z")
_It’s about time, it’s about space…"_ ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [December 9, 2012, 4:20am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/7 "2012-12-09T04:20:34Z")
> [@etv78](#): > > My thought: They aren’t seeing a sunrise/sunset, and that would be disorienting. ( **This** is why I stay out of GQ) Actually, on the ISS, they see one every 90 minutes… ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [December 9, 2012, 4:57am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/8 "2012-12-09T04:57:30Z")
> [@etv78](#): > > My thought: They aren’t seeing a sunrise/sunset, and that would be disorienting. ( **This** is why I stay out of GQ) There is, sometimes, a slight tendency to treat a good question as if it were a stupid question. This is regrettable, exactly for the reason you note: it keeps people away. As noted, the astronauts, from Gagarin onward, saw too many sunrises and sunsets. The earlier ones, at least, were also in a high stress environment. If one’s heart is pounding rapidly, time can seem to pass more slowly than it actually does. (I’m told this is particularly notable for talk-radio hosts on the first few broadcasts of their careers. They start at 7:08, talk for what seems like an hour, glance at the clock, and are astonished to see…7:12.) Now, it’d be pointless to mention relativistic effects… 🙂 ---
**Author:** ![etv78](https://avatars.discourse-cdn.com/v4/letter/e/d78d45/32.png) [@etv78](https://boards.straightdope.com/u/etv78)\ **Post date:** [December 9, 2012, 5:40am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/9 "2012-12-09T05:40:37Z")
> [@panache45](#): > > Even people in total sensory deprivation experience time. Why wouldn’t astronauts? Or do you mean they experience time, but have difficulty measuring its passage? This is more what I’m thinking. (or not) 😃 ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [December 9, 2012, 3:34pm UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/10 "2012-12-09T15:34:38Z")
They don’t experience quite as much time as we here in the full gravitational field of earth. An extremely accurate atomic clock was once sent on a plane trip around the world and lost an extremely tiny fraction of a second from being in slightly lower gravity. An astronaut is in free fall and feels no gravity at all. ---
**Author:** ![RaftPeople](https://avatars.discourse-cdn.com/v4/letter/r/6f9a4e/32.png) [@RaftPeople](https://boards.straightdope.com/u/RaftPeople)\ **Post date:** [December 9, 2012, 6:21pm UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/11 "2012-12-09T18:21:28Z")
Research in long term light deprived environments showed people shifted towards a 25 hour clock. Not sure what happens in space but clearly we have some internal mechanisms that aren’t completely dependent on the regular rising of the sun. ---
**Author:** ![Jake](https://avatars.discourse-cdn.com/v4/letter/j/f475e1/32.png) [@Jake](https://boards.straightdope.com/u/Jake)\ **Post date:** [December 9, 2012, 7:02pm UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/12 "2012-12-09T19:02:16Z")
> [@etv78](#): > > My thought: They aren’t seeing a sunrise/sunset, and that would be disorienting. ( **This** is why I stay out of GQ) Please stick around. This is an informative and sometimes funny part of the board. Don’t let us scare you, all questions are welcome. Again, welcome! ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [December 10, 2012, 11:50am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/13 "2012-12-10T11:50:34Z")
> [@Jake](#): > > Please stick around. This is an informative and sometimes funny part of the board. Don’t let us scare you, all questions are welcome. > Again, welcome! Hasn’t the OP been around for years? _checks_ Ten years in fact. Thought the name was familiar. ---
**Author:** ![cjepson](https://avatars.discourse-cdn.com/v4/letter/c/a9adbd/32.png) [@cjepson](https://boards.straightdope.com/u/cjepson)\ **Post date:** [December 10, 2012, 3:16pm UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/14 "2012-12-10T15:16:16Z")
> [@BMalion](#): > > _It’s about time, it’s about space…"_ Wow, somebody else remembers that? ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [December 10, 2012, 3:22pm UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/15 "2012-12-10T15:22:03Z")
> [@etv78](#): > > Do astronauts feel the pass of time while in orbit? Certainly. Due to time dilatation though time is actually slightly (VERY slightly) slower in orbit relative to the Earth. They don’t notice it (they wouldn’t notice it if they were traveling near the speed of light in their reference frame…it would all look normal to them, though an outside observer would see it very differently), but it’s measurably different for the Astronauts in orbit than it is on Earth. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [December 10, 2012, 3:31pm UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/16 "2012-12-10T15:31:21Z")
> [@RaftPeople](#): > > Research in long term light deprived environments showed people shifted towards a 25 hour clock. Not sure what happens in space but clearly we have some internal mechanisms that aren’t completely dependent on the regular rising of the sun. I recall an experiment many years ago in which a test subject spent several months isolated in an underground cave. He had comfortable living quarters - heat, a bed, artificial lighting, communication with colleagues on the surface etc. - but was not exposed to any sunlight, and did not have access to any sort of artifical timekeeping device. As you describe, he tended toward a 25-hour sleep-wake cycle. I suspect the same would be true of of the astronauts, if they were not allowed access to clocks. I would guess that deliberately staying in synch with the work cycle of the folks at ground control - whether that’s in Russia or the US or elsewhere - helps them stay well rested so that they can work effectively when ground control is fully staffed during the day. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [December 10, 2012, 4:51pm UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/17 "2012-12-10T16:51:01Z")
Do astronauts and the sleep cycle test subjects take Vitamin D supplements? Or does that screw up the data on the sleep-cycle guys? ---
**Author:** ![Floater](https://avatars.discourse-cdn.com/v4/letter/f/dc4da7/32.png) [@Floater](https://boards.straightdope.com/u/Floater)\ **Post date:** [December 11, 2012, 10:20am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/18 "2012-12-11T10:20:28Z")
> [@Hari\_Seldon](#): > > They don’t experience quite as much time as we here in the full gravitational field of earth. An extremely accurate atomic clock was once sent on a plane trip around the world and lost an extremely tiny fraction of a second from being in slightly lower gravity. Gravity has got nothing to do with it. It’s about speed, or should I say relative speed. The faster an object, e.g. a space ship, moves the slower the time flows **as noted by an outside observer**. Inside the space ship time is as normal as ever. Einstein calculated this and the experiment you mentioned confirmed it. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [December 11, 2012, 11:12am UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/19 "2012-12-11T11:12:09Z")
> [@Floater](#): > > Gravity has got nothing to do with it. It’s about speed, or should I say relative speed. The faster an object, e.g. a space ship, moves the slower the time flows **as noted by an outside observer**. Inside the space ship time is as normal as ever. Einstein calculated this and the experiment you mentioned confirmed it. That’s only the special relativistic part; in general relativity, gravity is indeed responsible for time dilation effects. ---
**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:** [December 11, 2012, 2:34pm UTC](https://boards.straightdope.com/t/astronauts-and-passage-of-time/643481/20 "2012-12-11T14:34:39Z")
Indeed. The gravitational effect is not only larger than the speed effect, it’s in the opposite direction, so a calculation based only on the speed will fail horribly.