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Science Forum Index » Space - Shuttle Forum » Time on shuttle and ISS......
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 Posted: Sat Jun 28, 2008 8:14 am |
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Guest
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Hi,
Are there any time sensitive instruments or experiments on the ISS
that have to be adjusted for time dilation?
If so, how often would they have to be adjusted? I imagine it
wouldn't be until after many months?
Or do they even need to worry about keeping the same time frame of
reference as the Earth? |
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| Posted: Sat Jun 28, 2008 2:50 pm |
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Guest
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eric_nospam08 at (no spam) yahoo.com wrote:
Quote: Hi,
Are there any time sensitive instruments or experiments on the ISS
that have to be adjusted for time dilation?
If so, how often would they have to be adjusted? I imagine it
wouldn't be until after many months?
Or do they even need to worry about keeping the same time frame of
reference as the Earth?
On the ISS time display, they list GMT (Greenwich Mean Time) and AOBT
(Adjusted On Board Time), which is usually a few seconds off. Someone else
will have to explain whether that difference is due to relativistic
effects, but that is the explanation I heard. They are going at (no spam) 0.002% of
the speed of light, so some effects would be expected.
Mike Ross |
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| Greg D. Moore (Strider)... |
| Posted: Sat Jun 28, 2008 8:03 pm |
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<eric_nospam08 at (no spam) yahoo.com> wrote in message
news:a3ad3817-4d7f-4386-9a5e-350dda0df817 at (no spam) 34g2000hsh.googlegroups.com...
Quote: Hi,
Are there any time sensitive instruments or experiments on the ISS
that have to be adjusted for time dilation?
Per the subjectline, I don't think there's anything on the shuttle that
sensitive, it uses MET for everything I believe. (well one could argue the
GPS guidance system doesn't :-)
Quote:
If so, how often would they have to be adjusted? I imagine it
wouldn't be until after many months?
My guess is any experiments are pretty self-contained. (Though there was a
relatively experiment planned for the outside of the ISS to test I believe
frame dragging.)
And in fact something like GPS has to take into both special relativity and
general relativity.
Quote: Or do they even need to worry about keeping the same time frame of
reference as the Earth?
--
Greg Moore
SQL Server DBA Consulting Remote and Onsite available!
Email: sql (at) greenms.com http://www.greenms.com/sqlserver.html |
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| OM... |
| Posted: Sat Jun 28, 2008 9:05 pm |
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Guest
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On Sat, 28 Jun 2008 21:03:53 -0400, "Greg D. Moore \(Strider\)"
<mooregr_deleteth1s at (no spam) greenms.com> wrote:
Quote: Per the subjectline, I don't think there's anything on the shuttle that
sensitive, it uses MET for everything I believe.
....Well, like the ad says, "Get MET, it pays."
OM
--
]=====================================[
] OMBlog - http://www.io.com/~o_m/omworld [
] Let's face it: Sometimes you *need* [
] an obnoxious opinion in your day! [
]=====================================[ |
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| Dand... |
| Posted: Sat Jun 28, 2008 11:06 pm |
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Guest
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Quote: On the ISS time display, they list GMT (Greenwich Mean Time) and AOBT
(Adjusted On Board Time), which is usually a few seconds off. Someone
else
will have to explain whether that difference is due to relativistic
effects, but that is the explanation I heard. They are going at (no spam) 0.002% of
the speed of light, so some effects would be expected.
I believe the lack of gravity has the bigger effect than the speed, as time
dilates depending on gravity also. |
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| Brian Gaff... |
| Posted: Sun Jun 29, 2008 4:55 am |
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Guest
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Time dilation at a constant velocity just around the planet? Now that would
be a heck of a long time to see a reasonable change I'd have thought.
Brian
--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email: briang1 at (no spam) blueyonder.co.uk
______________________________________________________________________________________________________________
<eric_nospam08 at (no spam) yahoo.com> wrote in message
news:a3ad3817-4d7f-4386-9a5e-350dda0df817 at (no spam) 34g2000hsh.googlegroups.com...
Quote: Hi,
Are there any time sensitive instruments or experiments on the ISS
that have to be adjusted for time dilation?
If so, how often would they have to be adjusted? I imagine it
wouldn't be until after many months?
Or do they even need to worry about keeping the same time frame of
reference as the Earth?
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| Brian Gaff... |
| Posted: Sun Jun 29, 2008 4:57 am |
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Guest
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Interesting as of course you are in fact in free fall. Gravity is still
there of course or you would simply be going in a straight line.
Brian
--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email: briang1 at (no spam) blueyonder.co.uk
______________________________________________________________________________________________________________
"Dand" <fake at (no spam) email.net> wrote in message
news:48670a52$0$13944$afc38c87 at (no spam) news.optusnet.com.au...
Quote: On the ISS time display, they list GMT (Greenwich Mean Time) and AOBT
(Adjusted On Board Time), which is usually a few seconds off. Someone
else
will have to explain whether that difference is due to relativistic
effects, but that is the explanation I heard. They are going at (no spam) 0.002% of
the speed of light, so some effects would be expected.
I believe the lack of gravity has the bigger effect than the speed, as
time dilates depending on gravity also.
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| Dr J R Stockton... |
| Posted: Sun Jun 29, 2008 8:07 am |
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Guest
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In sci.space.shuttle message <BtydnTzBQ4-DC_vVnZ2dnUVZ_q3inZ2d at (no spam) comcast.c
om>, Sat, 28 Jun 2008 14:50:52, mike_l_rossREMOVE at (no spam) REMOVEcomcast.net
posted:
Quote:
On the ISS time display, they list GMT (Greenwich Mean Time) and AOBT
(Adjusted On Board Time), which is usually a few seconds off. Someone else
will have to explain whether that difference is due to relativistic
effects, but that is the explanation I heard. They are going at (no spam) 0.002% of
the speed of light, so some effects would be expected.
Nearer 0.003% of c, I believe. ISS is ten years old; relativity at that
speed for 10 years should amount to well under a second.
For the approximate speed : light would circle the Earth in 1/7 second,
ISS takes 92 minutes.
--
(c) John Stockton, near London. * at (no spam) merlyn.demon.co.uk/?.?.Stockton at (no spam) physics.org
Web <URL:http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
Correct <= 4-line sig. separator as above, a line precisely "-- " (SoRFC1036)
Do not Mail News to me. Before a reply, quote with ">" or "> " (SoRFC1036) |
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| Greg D. Moore (Strider)... |
| Posted: Sun Jun 29, 2008 10:16 am |
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Guest
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"Dand" <fake at (no spam) email.net> wrote in message
news:48670a52$0$13944$afc38c87 at (no spam) news.optusnet.com.au...
Quote: On the ISS time display, they list GMT (Greenwich Mean Time) and AOBT
(Adjusted On Board Time), which is usually a few seconds off. Someone
else
will have to explain whether that difference is due to relativistic
effects, but that is the explanation I heard. They are going at (no spam) 0.002% of
the speed of light, so some effects would be expected.
I believe the lack of gravity has the bigger effect than the speed, as
time dilates depending on gravity also.
Umm, what lack of gravity?
You're moving in relation to the surface of the Earth, and you're in a
gravity field, but you're not lacking gravity.
--
Greg Moore
SQL Server DBA Consulting Remote and Onsite available!
Email: sql (at) greenms.com http://www.greenms.com/sqlserver.html |
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| ... |
| Posted: Mon Jun 30, 2008 3:43 pm |
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Guest
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Interesting comments. I have been following this thread.
I have also gone on to read that the ISS's frame of reference for 24
hours is ~26 microseconds (plus or minus a few microseconds, depending
on who's fuzzy math you are led to believe) slower than the Earth's 24
hour frame of reference.
Time for the old twins again. If you have two twins that born at
exactly the same time (C-section?) and one grows up to be, oh, say, a
farmer while the other grows up to be an astronaut, the astronaut twin
will be 260 microseconds younger than his farmer twin after spending
ten days in orbit.
Not exactly the fountain of youth, but it is pretty cool that the
shuttle and ISS are "time machines" even though they aren't very
efficient at it. |
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| Greg D. Moore (Strider)... |
| Posted: Mon Jun 30, 2008 8:56 pm |
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Guest
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<eric_nospam08 at (no spam) yahoo.com> wrote in message
news:9b47712a-d917-4c27-af96-86b1e6741010 at (no spam) m3g2000hsc.googlegroups.com...
Quote: Interesting comments. I have been following this thread.
I have also gone on to read that the ISS's frame of reference for 24
hours is ~26 microseconds (plus or minus a few microseconds, depending
on who's fuzzy math you are led to believe) slower than the Earth's 24
hour frame of reference.
Time for the old twins again. If you have two twins that born at
exactly the same time (C-section?) and one grows up to be, oh, say, a
farmer while the other grows up to be an astronaut, the astronaut twin
will be 260 microseconds younger than his farmer twin after spending
ten days in orbit.
Personally I'd love to come back in about 100-150 years....
(there was a classic twilight zone episode that involved that).
Quote:
Not exactly the fountain of youth, but it is pretty cool that the
shuttle and ISS are "time machines" even though they aren't very
efficient at it.
--
Greg Moore
SQL Server DBA Consulting Remote and Onsite available!
Email: sql (at) greenms.com http://www.greenms.com/sqlserver.html |
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