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How soon until Space Colonization is a viable reality?
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fretgod99


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PostPosted: Tue Nov 13, 2012 11:33 am    Post subject: Reply with quote

milanb wrote:
fretgod99 wrote:
milanb wrote:
[UMN] wrote:
3. You do not end up in the future if you travel near the speed of light. That is not how relativity works.

http://en.wikipedia.org/wiki/Space_travel_using_constant_acceleration#Planetary_reference_frame
That's just basically restating the differences of how observers experience the passage of time based upon frame of reference. Or am I missing something?
It's called time dilation.

http://en.wikipedia.org/wiki/Time_dilation

There's also length contraction.

http://en.wikipedia.org/wiki/Length_contraction

It's why you don't need to travel beyond the speed of light to travel between the stars in a reasonable period of time. All you need to do is keep accelerating.

The down side to all this is that the faster and longer you accelerate, the more earth years go by for every year you experience as the traveller.
I know, we were talking about that earlier. I wasn't sure if you were refuting [UMN] or bolstering his point, which is why I asked. Think we're all in agreement, though. Was just trying to clarify. No worries.
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milanb


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PostPosted: Tue Nov 13, 2012 11:57 am    Post subject: Reply with quote

fretgod99 wrote:
milanb wrote:
fretgod99 wrote:
milanb wrote:
[UMN] wrote:
3. You do not end up in the future if you travel near the speed of light. That is not how relativity works.

http://en.wikipedia.org/wiki/Space_travel_using_constant_acceleration#Planetary_reference_frame
That's just basically restating the differences of how observers experience the passage of time based upon frame of reference. Or am I missing something?
It's called time dilation.

http://en.wikipedia.org/wiki/Time_dilation

There's also length contraction.

http://en.wikipedia.org/wiki/Length_contraction

It's why you don't need to travel beyond the speed of light to travel between the stars in a reasonable period of time. All you need to do is keep accelerating.

The down side to all this is that the faster and longer you accelerate, the more earth years go by for every year you experience as the traveller.
I know, we were talking about that earlier. I wasn't sure if you were refuting [UMN] or bolstering his point, which is why I asked. Think we're all in agreement, though. Was just trying to clarify. No worries.


I was responding to this post:

[UMN] wrote:
First of all, let’s get the more blatant statements in this thread out of the way:

1. Travel outside of the solar system is flat out impossible until we figure out FTL travel (if it is possible) or something equally as impressive.

2. Venus is not inhabitable. Period.

3. You do not end up in the future if you travel near the speed of light. That is not how relativity works.


I disagree with points (1) and (3).

If you can accelerate constantly at 1g for five years you can go to Alpha Centauri and return to earth, in which time six earth years would have elapsed.
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fretgod99


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PostPosted: Tue Nov 13, 2012 12:20 pm    Post subject: Reply with quote

milanb wrote:
fretgod99 wrote:
milanb wrote:
fretgod99 wrote:
milanb wrote:
[UMN] wrote:
3. You do not end up in the future if you travel near the speed of light. That is not how relativity works.

http://en.wikipedia.org/wiki/Space_travel_using_constant_acceleration#Planetary_reference_frame
That's just basically restating the differences of how observers experience the passage of time based upon frame of reference. Or am I missing something?
It's called time dilation.

http://en.wikipedia.org/wiki/Time_dilation

There's also length contraction.

http://en.wikipedia.org/wiki/Length_contraction

It's why you don't need to travel beyond the speed of light to travel between the stars in a reasonable period of time. All you need to do is keep accelerating.

The down side to all this is that the faster and longer you accelerate, the more earth years go by for every year you experience as the traveller.
I know, we were talking about that earlier. I wasn't sure if you were refuting [UMN] or bolstering his point, which is why I asked. Think we're all in agreement, though. Was just trying to clarify. No worries.
I was responding to this post:

[UMN] wrote:
First of all, let’s get the more blatant statements in this thread out of the way:

1. Travel outside of the solar system is flat out impossible until we figure out FTL travel (if it is possible) or something equally as impressive.

2. Venus is not inhabitable. Period.

3. You do not end up in the future if you travel near the speed of light. That is not how relativity works.
I disagree with points (1) and (3).

If you can accelerate constantly at 1g for five years you can go to Alpha Centauri and return to earth, in which time six earth years would have elapsed.
That doesn't really dispute his points, though.

1. Constant Acceleration engines are basically theoretical at this point. They're definitely not practical at this time for actual use. Also, I'm willing to be coming up with such an engine would constitute "something equally as impressive". Come up with an engine capable of constant 1g acceleration that can be used to transport humans, supplies, etc. and it's possible. That, to my knowledge, hasn't been developed yet.

3. You're not traveling into the "future" when traveling at any significant fraction of the Speed of Light; you're simply experiencing time at a different rate. Perhaps it's a semantic thing but "traveling into the future" connotes "jumping" or having "breaks" in time, meaning you're not experiencing time fluidly.
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milanb


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PostPosted: Tue Nov 13, 2012 12:47 pm    Post subject: Reply with quote

fretgod99 wrote:


1. Constant Acceleration engines are basically theoretical at this point. They're definitely not practical at this time for actual use. Also, I'm willing to be coming up with such an engine would constitute "something equally as impressive". Come up with an engine capable of constant 1g acceleration that can be used to transport humans, supplies, etc. and it's possible. That, to my knowledge, hasn't been developed yet.



Yes, and the technical difficulties may never be overcome. But it's not ridiculously impossible that someone may develop an efficient means of turning e.g. nuclear fusion into mechanical energy.

fretgod99 wrote:


3. You're not traveling into the "future" when traveling at any significant fraction of the Speed of Light; you're simply experiencing time at a different rate. Perhaps it's a semantic thing but "traveling into the future" connotes "jumping" or having "breaks" in time, meaning you're not experiencing time fluidly.


Here was my original post to which he was ostensibly responding:

milanb wrote:
vike daddy wrote:
49ersfan wrote:
42 light years is relatively small, when i've read that our galaxy itself is 100,000 light years long, compared to the known universe which itself is supposedly 100 billion light years. So 42? Almost like a cakewalk.

as you are discovering, 42 LY is a tiny distance in the cosmic road map, but an enormous one for our present technology, or anything immediately foreseable.

our Moon is about 2 light seconds away, our Sun is about eight light minutes away. 42 years is an enormous distance to transit, not to mention what support help would there be from an Earth command base if a one-time back and forth conversation would take 84 years to complete?


Even if you could travel at anything close to the speed of light, time would slow down around you and you could be thousands of years into the future by the time you reached your destination.


It should have been pretty clear that I was talking about time slowing down for the traveller relative to Earth, and that I was attempting to explain it in plain English.
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Flaccomania


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PostPosted: Tue Nov 13, 2012 1:01 pm    Post subject: Reply with quote

Maybe I don't fully understand it, but even if you were experiencing time at a different rate relative to Earth, would you not age the same, just technically "slower/faster"? As in, yeah, it may only be 1 months time from your point of reference going that fast, but 6 years on Earth -- but would you body not still age the same amount in that "1 month" as it would have in 6 years on Earth?
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fretgod99


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PostPosted: Tue Nov 13, 2012 1:10 pm    Post subject: Reply with quote

Flaccomania wrote:
Maybe I don't fully understand it, but even if you were experiencing time at a different rate relative to Earth, would you not age the same, just technically "slower/faster"? As in, yeah, it may only be 1 months time from your point of reference going that fast, but 6 years on Earth -- but would you body not still age the same amount in that "1 month" as it would have in 6 years on Earth?
No. If you experience "1 month" of time passage, you would only age "1 month".

http://en.wikipedia.org/wiki/Twin_paradox#Specific_example

Quote:
If twins are born on the day the ship leaves, and one goes on the journey while the other stays on Earth, they will meet again when the traveler is 6 years old and the stay-at-home twin is 10 years old. The calculation illustrates the usage of the phenomenon of length contraction and the experimentally verified phenomenon of time dilation to describe and calculate consequences and predictions of Einstein's special theory of relativity.


That's what gets confusing about Relativity for a lot of people. Time isn't the constant we are led to believe it is. The rate of the passage of time changes depending upon acceleration and gravity, for instance.

EDIT: For clarity, meaning there's not one standard, unchanging barometer of time that all travelers can be compared to.
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Can somebody give me a good reason there's not a giant statue to fret somewhere?


Last edited by fretgod99 on Tue Nov 13, 2012 1:16 pm; edited 1 time in total
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fretgod99


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PostPosted: Tue Nov 13, 2012 1:14 pm    Post subject: Reply with quote

milanb wrote:
fretgod99 wrote:
1. Constant Acceleration engines are basically theoretical at this point. They're definitely not practical at this time for actual use. Also, I'm willing to be coming up with such an engine would constitute "something equally as impressive". Come up with an engine capable of constant 1g acceleration that can be used to transport humans, supplies, etc. and it's possible. That, to my knowledge, hasn't been developed yet.
Yes, and the technical difficulties may never be overcome. But it's not ridiculously impossible that someone may develop an efficient means of turning e.g. nuclear fusion into mechanical energy.
That's fair, but I don't think it's actually disputing [UMN] on that point. Unless we actually develop the technology to travel FTL or come up with some equally impressive developments in propulsion, than it's impossible to be able to muster meaningful and useful interplanetary travel, let alone interstellar travel.

Quote:
fretgod99 wrote:
3. You're not traveling into the "future" when traveling at any significant fraction of the Speed of Light; you're simply experiencing time at a different rate. Perhaps it's a semantic thing but "traveling into the future" connotes "jumping" or having "breaks" in time, meaning you're not experiencing time fluidly.
It should have been pretty clear that I was talking about time slowing down for the traveller relative to Earth, and that I was attempting to explain it in plain English.
Fair enough. That's basically what I assumed in response to him as well.
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RainbowCarebear


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PostPosted: Tue Nov 13, 2012 1:15 pm    Post subject: Reply with quote

How do we know NASA isn't already doing it Confused
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Packman Luke


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PostPosted: Tue Nov 13, 2012 1:20 pm    Post subject: Reply with quote

I remember all of this time lapse mumbo jumbo from when I read (I think) the second Ender's book a while back. I understand how the words make sense and what needs to happen, but I still don't really follow what exactly is happening.
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Green90


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PostPosted: Tue Nov 13, 2012 1:41 pm    Post subject: Reply with quote

EliteTexan80 wrote:
[UMN] wrote:
as someone with degrees in both aerospace engineering and astrophysics, this is the funniest thread I have seen in a while. some of the replies here are priceless.

Laughing


Oh yeah? Well, I had a fling with an Ansari a few weeks back on Thessia. Would be going back, but I heard the Reapers really did a number to that planet.

(For those of you who don't get my references in this thread - do me a solid, get yourself a copy of Mass Effect 2 and Mass Effect 3, play 'em both a lot, and thank me later).


You know ET, for as many Mass Effect plugs as you give I'd think you be able to spell Asari right. Or did she screw with your mind... if you know what I mean *wink wink nudge nudge*.

And not the first ME?
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EliteTexan80


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PostPosted: Tue Nov 13, 2012 2:11 pm    Post subject: Reply with quote

Green90 wrote:
EliteTexan80 wrote:
[UMN] wrote:
as someone with degrees in both aerospace engineering and astrophysics, this is the funniest thread I have seen in a while. some of the replies here are priceless.

Laughing


Oh yeah? Well, I had a fling with an Ansari a few weeks back on Thessia. Would be going back, but I heard the Reapers really did a number to that planet.

(For those of you who don't get my references in this thread - do me a solid, get yourself a copy of Mass Effect 2 and Mass Effect 3, play 'em both a lot, and thank me later).


You know ET, for as many Mass Effect plugs as you give I'd think you be able to spell Asari right. Or did she screw with your mind... if you know what I mean *wink wink nudge nudge*.

Yeah, I romanced her, so she screwed with my mind. Also, I have fat fingers. I'm a clumsy typer. Sad

Quote:
And not the first ME?

Only have the PS3 version, so I won't get the 1st one until the trilogy is released early next month. You better bet yoour boy ET is ON that. Very Happy
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I wanna be a mod.

vastly over rated.
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Gmen4ev


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PostPosted: Tue Nov 13, 2012 2:12 pm    Post subject: Reply with quote

RainbowCarebear wrote:
How do we know NASA isn't already doing it Confused




CONSPIRACY!!!!!
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milanb


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PostPosted: Tue Nov 13, 2012 2:14 pm    Post subject: Reply with quote

fretgod99 wrote:
That's fair, but I don't think it's actually disputing [UMN] on that point. Unless we actually develop the technology to travel FTL or come up with some equally impressive developments in propulsion, than it's impossible to be able to muster meaningful and useful interplanetary travel, let alone interstellar travel.



I'm not disputing it, just disagreeing with it.

I believe that developing a propulsion system that can accelerate itself and its payload at 1g for ~10 years is still very much in the realm of science fiction, but it is not nearly as far removed from the realm of possibility as e.g. FTL or wormhole travel.
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Flaccomania


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PostPosted: Tue Nov 13, 2012 2:29 pm    Post subject: Reply with quote

fretgod99 wrote:
Flaccomania wrote:
Maybe I don't fully understand it, but even if you were experiencing time at a different rate relative to Earth, would you not age the same, just technically "slower/faster"? As in, yeah, it may only be 1 months time from your point of reference going that fast, but 6 years on Earth -- but would you body not still age the same amount in that "1 month" as it would have in 6 years on Earth?
No. If you experience "1 month" of time passage, you would only age "1 month".

http://en.wikipedia.org/wiki/Twin_paradox#Specific_example

Quote:
If twins are born on the day the ship leaves, and one goes on the journey while the other stays on Earth, they will meet again when the traveler is 6 years old and the stay-at-home twin is 10 years old. The calculation illustrates the usage of the phenomenon of length contraction and the experimentally verified phenomenon of time dilation to describe and calculate consequences and predictions of Einstein's special theory of relativity.


That's what gets confusing about Relativity for a lot of people. Time isn't the constant we are led to believe it is. The rate of the passage of time changes depending upon acceleration and gravity, for instance.

EDIT: For clarity, meaning there's not one standard, unchanging barometer of time that all travelers can be compared to.


I still don't quite understand it -- I saw this in the article you posted, but it doesn't go into the detail I hoped:

Quote:
It would probably be prudent to mention: All processes—chemical, biological, measuring apparatus functioning, human perception involving the eye and brain, the communication of force—everything, is constrained by the speed of light. There is clock functioning at every level, dependent on light speed and the inherent delay at even the atomic level. Thus, we speak of the "twin paradox", involving biological aging. It is in no way different from clock time-keeping. Biological aging is equated to clock time-keeping by John A. Wheeler in Spacetime Physics.


I understand the issue with the differences in "calculated" age where one baby would be 1 year old and the other 6 years old or whatever. But biologically, I guess I wouldn't expect the body to slow it's aging process by the same value. That is, from the viewpoint of somebody on Earth, one twin living 80 years and the other living 240 years (6x as long) simply because they are traveling at a higher speed.

Not sure if I'm explaining my difficulty understanding very clearly: For instance, again let's use the example from your article: They mention the traveling twin would be 6 years old, the stay at home twin being 10 years old. Biologically, would they be at the same point? Let's say we let this occur for 10x as long -- a 60 year old traveling twin and an 80 year old Earth twin -- are their bodies at the same biological point? Ie, close to the end of their lives?
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Green90


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PostPosted: Tue Nov 13, 2012 2:41 pm    Post subject: Reply with quote

EliteTexan80 wrote:
Green90 wrote:
EliteTexan80 wrote:
[UMN] wrote:
as someone with degrees in both aerospace engineering and astrophysics, this is the funniest thread I have seen in a while. some of the replies here are priceless.

Laughing


Oh yeah? Well, I had a fling with an Ansari a few weeks back on Thessia. Would be going back, but I heard the Reapers really did a number to that planet.

(For those of you who don't get my references in this thread - do me a solid, get yourself a copy of Mass Effect 2 and Mass Effect 3, play 'em both a lot, and thank me later).


You know ET, for as many Mass Effect plugs as you give I'd think you be able to spell Asari right. Or did she screw with your mind... if you know what I mean *wink wink nudge nudge*.

Yeah, I romanced her, so she screwed with my mind. Also, I have fat fingers. I'm a clumsy typer. Sad

Quote:
And not the first ME?

Only have the PS3 version, so I won't get the 1st one until the trilogy is released early next month. You better bet yoour boy ET is ON that. Very Happy


Oh good, I was just hoping you didn't mean Aziz Ansari:


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