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 MobileRead Forums Seriously thoughtful The concept of 'TIME'

08-23-2010, 02:05 PM   #61
HarryT
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 Originally Posted by WT Sharpe Great video. We know that astronauts in our day have already traveled through time. Only microseconds, to be sure, but the time dilation experienced by lunar astronauts away from the earth's gravitational field (which also causes distortions of time), and the distance into the future they have traveled, is measurable.
In the case of the Apollo astronauts, there were two competing factors at work.

1. The speed of their travel would cause a small amount of time dilation, which would result in time passing a little more slowly for them than for people back on Earth.

2. They spent time in a slightly weaker gravitational field than people back on Earth did. This would result in time passing a little more quickly than it did back on Earth.

Of these, the time dilation effect would be by far the greater (although still very, very small).

08-23-2010, 02:08 PM   #62
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 Originally Posted by Sparrow And away from everyone else??
Well, of course, I am the center of the universe after all

08-23-2010, 02:11 PM   #63
dsvick
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Quote:
 Originally Posted by WT Sharpe Great video. We know that astronauts in our day have already traveled through time.
Quote:
 Originally Posted by HarryT In the case of the Apollo astronauts, there were two competing factors at work. 1. The speed of their travel would cause a small amount of time dilation, which would result in time passing a little more slowly for them than for people back on Earth. 2. They spent time in a slightly weaker gravitational field than people back on Earth did. This would result in time passing a little more quickly than it did back on Earth. Of these, the time dilation effect would be by far the greater (although still very, very small).
I think the best example are the pilots of some of the jets, like the SR-71, the Concorde, and others. Again, the difference is very, very small, but I bet measurable.

08-23-2010, 02:16 PM   #64
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 Originally Posted by dsvick I think the best example are the pilots of some of the jets, like the SR-71, the Concorde, and others. Again, the difference is very, very small, but I bet measurable.
Certainly; it's been measured. A few years ago someone took two atomic clocks and precisely synchronised them. One of them then "stayed at home", while the other was flown around the world in commercial airliners. When it came back, the clock that had been on its travels was a few nanoseconds behind the one that had stayed in the laboratory, even though they were still measuring time at precisely the same rate. The amount of time lost by the travelling clock was precisely in according with what relativity predicted.

08-23-2010, 04:19 PM   #65
WT Sharpe
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Quote:
 Originally Posted by HarryT In the case of the Apollo astronauts, there were two competing factors at work. 1. The speed of their travel would cause a small amount of time dilation, which would result in time passing a little more slowly for them than for people back on Earth. 2. They spent time in a slightly weaker gravitational field than people back on Earth did. This would result in time passing a little more quickly than it did back on Earth. Of these, the time dilation effect would be by far the greater (although still very, very small).
Quite true. I had mentioned that in an earlier post in another thread around here somewhere, but I decided to omit those details in this post for sake of brevity. Gravity and acceleration both affect the flow of time.

08-24-2010, 01:09 AM   #66
MickeyC
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 Originally Posted by WT Sharpe Quite true. I had mentioned that in an earlier post in another thread around here somewhere, but I decided to omit those details in this post for sake of brevity. Gravity and acceleration both affect the flow of time.
I've read that scientists have placed atomic clocks at the top and bottom of tall water towers and discovered, as predicted by General Relativity, that the clock at the top (less affected by gravity) does run faster than the one at the bottom.

Consequently, if you and your twin have to share a bunk bed, take the lower one; you'll age slower. Okay, well, it probably take a million years to equal a couple of seconds.

 08-24-2010, 03:54 AM #67 lene1949 Wizard     Posts: 1,955 Karma: 213930 Join Date: Oct 2009 Location: Ipswich, Queensland, Australia Device: Kindle 2, Sony PRS 650, Ipod Touch Speed of light is what WE calculated it should be.. What if our sense of 'time' is not correct? I sometimes dream a whole story/book/movie in 4 seconds flat.. How can I do this? How can I fit all that information into those few seconds?
08-24-2010, 04:00 AM   #68
HarryT
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 Originally Posted by lene1949 Speed of light is what WE calculated it should be..
What do you mean "what we calculated it to be"? The speed of light is experimentally measured, it's not calculated.

 08-24-2010, 04:42 AM #69 Druid_Elf Zealot   Posts: 109 Karma: 612 Join Date: Jul 2010 Location: belgium Device: none Yup HarryT is right: http://www.xs4all.nl/~johanw/PhysFAQ...measure_c.html List of the experiments of how speed of light was deduced
08-24-2010, 08:27 AM   #70
WT Sharpe
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 Originally Posted by cassidym I've read that scientists have placed atomic clocks at the top and bottom of tall water towers and discovered, as predicted by General Relativity, that the clock at the top (less affected by gravity) does run faster than the one at the bottom. Consequently, if you and your twin have to share a bunk bed, take the lower one; you'll age slower. Okay, well, it probably take a million years to equal a couple of seconds.
It's true that people in the upper stories of high towers age faster than people who live on the ground floor, or more correctly, the people in the upper stories travel through time faster because they are further away from earth's gravity, which produces the same effect as acceleration. Of course, the differences are minuscule, and no one researching genealogies needs to concern themselves as to whether someone was born in the penthouse or the basement when assigning the exact time of birth to various relatives. Even if it were noticeable to outside observers, as in the famous thought experiment of the astronaut who travels close to the speed of light only to return and discover his twin brother is now an old man, the amount of time each experienced would be the same.

Last edited by WT Sharpe; 08-24-2010 at 08:35 AM.

08-25-2010, 05:04 AM   #71
Roger Parkinson
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 Originally Posted by TGS Suppose you have a meeting arranged for next Wednesday, then you get an email saying, "Sorry to mess you about but we are going to have the move the meeting forward a day." Is the meeting now on Tuesday or Thursday.
This is something I have been annoying people with for years now. Usually they seem to mean that moving something 'back' makes it 'later', but when I change my watch to move it 'back' it is to an earlier time. When I point this out they just call me a now-it-all (or worse) and I have no friends.

 08-25-2010, 09:26 PM #72 Williamlk Guru     Posts: 624 Karma: 700001 Join Date: Aug 2010 Location: New York Device: kindle In response to those who chimed in on the idea of an existence with no time at all, I have what I think is an interesting question; Inside a wormhole, wouldn't time (at least as we understand it) cease to exist?
 08-25-2010, 09:49 PM #73 badgoodDeb Wizard     Posts: 4,903 Karma: 16112951 Join Date: Jan 2008 Location: Chicago outskirts Device: Palms, K1, K3, K4s, iPad, iPhones, KV Have you ever read the long out of copyrite work "Flatland"? Skipping the bits about war, the societies in it ..... and how the 1-dimensioner's view 2-dimensioners, etc .... gives a very good feeling why someone *IN* an N-dimensional universe (i.e. our 4 dimensions including time) cannot even conceive of a larger dimension. They don't have words to describe it, and can't wrap their heads around the idea of more dimensions than they know. I find it useful for thinking of time as one of those "we can't even imagine it" dimensions -- i.e. a 5-dimensional being *can* move backwards in time, whereas we cannot. Actually, we can imagine it .... so that's a little different than the dimensions discussed, wherein one's brain can't even grasp a higher dimension than it is built in. But the book stretches the mind as regards to the more usual of our 3 dimensions. Very interesting read!
 08-25-2010, 09:56 PM #74 Williamlk Guru     Posts: 624 Karma: 700001 Join Date: Aug 2010 Location: New York Device: kindle I am definately going to check that book out. Thank you!
 08-25-2010, 10:05 PM #75 badgoodDeb Wizard     Posts: 4,903 Karma: 16112951 Join Date: Jan 2008 Location: Chicago outskirts Device: Palms, K1, K3, K4s, iPad, iPhones, KV It's available here at MR -- see the book section.

 Tags sci-fi, time