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Do you believe in extraterrestrial life?


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#101 ElBastardoVerde

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Posted 16 September 2012 - 09:45 AM

Seems like I opened a can of worms here. :ph34r:


It's not too hard.

#102 Nymh

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Posted 16 September 2012 - 09:45 AM

The math was fun. ^_^

#103 Sweeney

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Posted 16 September 2012 - 10:08 AM

You can try and ridicule me all you want and it just makes you both seem like baboons.

It is a logical explanation of the existence of everything. Just as good as any explanation they can teach at school, church, home, corner store, crack pipe, ect...


Well, no. Not really.

#104 Guest_coltom_*

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Posted 16 September 2012 - 10:22 AM

You can try and ridicule me all you want and it just makes you both seem like baboons.

It is a logical explanation of the existence of everything. Just as good as any explanation they can teach at school, church, home, corner store, crack pipe, ect...


I would concur that it is a fairly common science fiction idea, that intelligence evolves to the point that its mastery of time allows it to be its own creator. As many things, Asimov likely did one of the short best answers in
http://en.wikipedia....e_Last_Question
Certainly others have played with this theme, I have not, but it does seem like one of the possible end states of any intelligence, the others being resource deprivation extinction and external extinction.

Now, that is all predicated on the ability of time travel to exist.

P.S. Yes, I am agreeing with Yung.

Edited by coltom, 16 September 2012 - 10:24 AM.


#105 Sweeney

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Posted 16 September 2012 - 10:31 AM

P.S. Yes, I am agreeing with Yung.


No, you're not.
Yung stated that "time is just a concept", which it isn't. It's a fundamental property of the universe.

#106 Romy

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Posted 16 September 2012 - 11:04 AM

No, you're not.
Yung stated that "time is just a concept", which it isn't. It's a fundamental property of the universe.


THIS 100%.

Time is NOT a concept.

#107 Guest_coltom_*

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Posted 16 September 2012 - 01:30 PM

Time is a concept.
Linear time even more so.
Unidirectional time not only an unproven concept, but contrary to almost all theories of the universe.

Delta S is always positive, but the why, that is the question.

#108 Sweeney

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Posted 16 September 2012 - 01:36 PM

Surely something is either a concept, or it isn't... How can something be "more" of a concept than something else...?

And obviously there are concepts of time. But time itself is a property of the universe. You can't just decide that it's irrelevant and go hopping around the past on a whim.

#109 artificial

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Posted 16 September 2012 - 03:33 PM

And now we're on to semantics. Riveting discussion this.

#110 Guest_coltom_*

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Posted 16 September 2012 - 06:27 PM

And now we're on to semantics. Riveting discussion this.


A variety of slackers and "never made its" are arguing with a science fiction writing engineer. Now, I've got an advanced degree from one of the nation's best engineering schools, but hellfire I'm not qualified to argue the problems subatomic scale, where time appears to be reversible and the macro scale where it does not appear at all.

So what to expect, a discussion on the level of a lecture at the Niels Bohr Institute?

P.S. Except for Nymh, who stays mainly silent.

#111 Drakonid

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Posted 16 September 2012 - 06:30 PM

Now, I've got an advanced degree from one of the nation's best BUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUULLSHIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIT



#112 chess211

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Posted 17 September 2012 - 06:52 AM

Coltrom: Just as a clarification, time symmetry is not always found in the interaction of subatomic particles. While CPT symmetry is always found, there are a number of interactions that violate CP symmetry, thus T symmetry must also be broken at those levels. Thus time is not a true symmetry of the Standard Model of Particle Physics, which is currently the best model that we have. While the effect is small, this provides a slight preference for one direction of time compared to the other at the particle scale. It is also unconnected to the macroscopic idea of entropy, which is what we see as the cause of the macroscopic arrow of time.

The current belief of why we have a macroscopic arrow of time due to entropy is because for some reason the early universe was a state of very low entropy, if it had been a state of high entropy then there would be no arrow of time, as local processes could occur with little impact on the global entropy due to it already being at a high level.

#113 Guest_coltom_*

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Posted 17 September 2012 - 07:44 AM

Coltrom: Just as a clarification, time symmetry is not always found in the interaction of subatomic particles.

Ah, someone that knows enough to catch me when I over simplify. I should have said that some interactions of subatomic particles occur without respect to the arrow of time.

Are you really comfortable with the concept that time is simply a byproduct of entropy? Then why would the trick to time travel simply be that we need to make entropy increase in one part of the universe, decrease in another part, still creating a net positive S, yet allowing localized time travel? For that matter, it seems that the only real restriction on that is that total S of the the universe post time travel interaction must be greater than the total S of the universe-prime.

Hey, that's a great story idea, time travel is possible, but each interaction must increase the total entropy of the universe, speeding the eventual arrival at the state of dark energy expansion/quantum soup.

Wait, even better, dark energy is the by product of time travel!!!! Love it. The universe is speeding its expansion because of elder civilizations using time travel.

This is fun.


P.S. considering that the concept of dark expansive energy was just beginning to gain favor when I was in school, there is part of me that has a healthy skepticism of the Standard Model of Particle Physics. I don't fully grasp why neutrinos have mass, I'm really uncomfortable with the linkage of entropy and time. What I am pretty sure of, is if we exist as a civilization for another 100,000 years, we'll likely discover a whole lot of things unthought of in the first three and half centuries of physics (I'm starting with Newton)

Edited by coltom, 17 September 2012 - 07:56 AM.


#114 Sweeney

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Posted 17 September 2012 - 10:30 AM

[stuff]


All well and good, but you're yet to explain how a civilisation could explore 3.817×1032 ly3 of space in under a million years, without exceeding lightspeed.

#115 chess211

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Posted 17 September 2012 - 10:50 AM

All well and good, but you're yet to explain how a civilisation could explore 3.817×1032 ly3 of space in under a million years, without exceeding lightspeed.


Sweeney, if you are going to give the number you might as well give the more accurate one based on the evidence we have which has a radius of about 46 billion light years, due to the wonderful expansion of space is much larger than just using the age of the universe estimate.


Coltrom: You might have misunderstood what I said. It is not that time is a product of entropy, but that the direction of time is probably found from entropy. Time itself is understood as just being the 'fourth' dimension of the 4D manifold of general relativity. The trick of time travel in this understanding of the arrow of time would be to just be in a near maximal (global) entropy state, as a state of maximum (global) entropy does not have a preferred direction of time except for the mentioned rare particle events.

Lowering entropy in one area does not allow for time travel, as any process that requires the input of heat (such as any endothermic reaction) generally involves the local decrease of entropy but none of these processes are evidence of time travel.

Dark Energy is a concept unrelated to the direction of time, and also unrelated to the concept of entropy.

#116 Guest_coltom_*

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Posted 17 September 2012 - 11:07 AM

Coltrom: You might have misunderstood what I said. It is not that time is a product of entropy, but that the direction of time is probably found from entropy. Time itself is understood as just being the 'fourth' dimension of the 4D manifold of general relativity. The trick of time travel in this understanding of the arrow of time would be to just be in a near maximal (global) entropy state, as a state of maximum (global) entropy does not have a preferred direction of time except for the mentioned rare particle events.

Lowering entropy in one area does not allow for time travel, as any process that requires the input of heat (such as any endothermic reaction) generally involves the local decrease of entropy but none of these processes are evidence of time travel.

Dark Energy is a concept unrelated to the direction of time, and also unrelated to the concept of entropy.

Dark energy is causing the accelerated rate expansion of the universe, does not an expanded universe have more entropy? Since we don't know what dark energy is, only what it appears to be doing, .,.,

Ok, three observations.
The direction of time is generally believed to be from the past to future.
The fact that events in the arrow of time cause an increase of entropy.
Overall entropy always increases, except on an atomic scale.
It is possible to have a system where part of the system has an increase greater than the decrease in the other part. Thus, some parts do have an decrease in entropy, as long as the overall system shows a increase.

Still sounds like a neat plot device for a science fiction story.

P.S. Assume top ramjet speed of .1c, with solar deceleration greater than acceleration, assume a self replicating machine, producing multiple replicators at each G-class star. Then the total exploration of the Galaxy takes less than 2 million years to explore. Since exploration is done by sentient replicating machines, there isn't even the need for the host/creating species to survive.

I'm pretty sure that was Fredrick Pohl that did that math, I hope it wasn't Niven, Larry is jerk.

P.S. I really don't get what you, and others are trying to say when you say "It is not that time is a product of entropy, but that the direction of time is probably found from entropy." They seem almost like the same statement. Yet, time is linear and uniform, best as anyone can tell, but entropy is not.

Edited by coltom, 17 September 2012 - 11:10 AM.


#117 Sweeney

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Posted 17 September 2012 - 11:19 AM

Sweeney, if you are going to give the number you might as well give the more accurate one based on the evidence we have which has a radius of about 46 billion light years, due to the wonderful expansion of space is much larger than just using the age of the universe estimate.


I used an estimate of 45 billion lightyears, from memory, apparently slightly out of date. Apologies.

 

So, given the age of the universe, the amount of time for civilizations to evolve, and even with no FTL travel ram-jet fusion ships could have explored the whole universe, with self-replicating machines to either watch, conquer, or just play head games, WHERE ARE THE ALIENS

P.S. Assume top ramjet speed of .1c, with solar deceleration greater than acceleration, assume a self replicating machine, producing multiple replicators at each G-class star. Then the total exploration of the Galaxy takes less than 2 million years to explore. Since exploration is done by sentient replicating machines, there isn't even the need for the host/creating species to survive.


I would expect even you to know that galaxy and universe are not synonymous.
And that's not to mention the fact that you've doubled the supposed estimate without even acknowledging the fact.

(Very impressive, though, addressing my post without reading it.)

#118 chess211

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Posted 17 September 2012 - 11:43 AM

I used an estimate of 45 billion lightyears, from memory, apparently slightly out of date. Apologies.


It is fine. The answer does depend on assumptions about the size of the universe anyways, as it is always possible that the actual universe is smaller than that are what is seen on the edge has circumnavigated the universe before.

Anyways, any question of exploring the universe depends on the size of the universe. Currently there is no reason to assume that the observable universe is equivalent to the size of the universe. If you just restrict it to a single galaxy, then in the lifetime of the universe exploring a galaxy is technically possible, even if it is difficult.

As for the impact of the expanding universe on the entropy of the universe, that is not something that I am familiar with. I have not dealt with cosmological aspects of anything in my research, so I am not qualified to talk about it, which trying to find some papers about it.

Edited by chess211, 17 September 2012 - 11:44 AM.


#119 Guest_coltom_*

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Posted 17 September 2012 - 11:55 AM

Quite possibly that is an assumption from my chemical engineering thermodynamics, any expanding gas increases in entrophy. Since I don't know how to tie dark energy into traditional thermodynamics.,.,.,.,

My discussion, and Niven's Pohl's or Clarke's discussion of exploration has to be limited to the Galaxy. While the Galaxy is a small, small sliver of the Universe, most still believe large enough for there should be elder civilization, unless.,,..,

#120 Sweeney

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Posted 17 September 2012 - 11:58 AM

My discussion, and Niven's Pohl's or Clarke's discussion of exploration has to be limited to the Galaxy. While the Galaxy is a small, small sliver of the Universe, most still believe large enough for there should be elder civilization, unless.,,..,


Then you probably shouldn't have said universe.
Your inability to admit a simple mistake is mindblowing.

#121 liquidnails

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Posted 22 January 2013 - 07:50 PM

It' possible, but I'm not going to take a firm stand either side until we are much more advanced in space exploration...

Considering the fact that they have found traces of water on places like Mars, it's quite possible...


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