Author Topic: Information & knowledge  (Read 16374 times)

cyberman

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Re: Information & knowledge
« Reply #50 on: July 21, 2015, 07:34:25 PM »
If the universe is infinite, why is the night sky dark? given infinite space, every line of sight would end with a star - why would there be so much black?

Andy

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Re: Information & knowledge
« Reply #51 on: July 21, 2015, 07:56:10 PM »
The further away something is, the faster it is moving away. If a galaxy is so far away that the rate of expansion exceeds the speed of light, then the light from it will never reach us.

I'm open to correction on that.

cyberman

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Re: Information & knowledge
« Reply #52 on: July 21, 2015, 07:58:01 PM »
The further away something is, the faster it is moving away. If a galaxy is so far away that the rate of expansion exceeds the speed of light, then the light from it will never reach us.

I'm open to correction on that.

But hasn't it been travelling towards us for an infinite amount of time?
Does observation support the conjecture that the universe is expanding at faster than the speed of light?

Andy

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Re: Information & knowledge
« Reply #53 on: July 21, 2015, 08:26:42 PM »
Seems I was wrong. Good vid here that explains it better than I can.

http://youtu.be/XBr4GkRnY04

jeremyp

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Re: Information & knowledge
« Reply #54 on: July 21, 2015, 08:33:15 PM »
If the universe is infinite, why is the night sky dark? given infinite space, every line of sight would end with a star - why would there be so much black?

That's Olbers' paradox.  It doesn't apply in this Universe because time doesn't go back to infinity.
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cyberman

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Re: Information & knowledge
« Reply #55 on: July 21, 2015, 08:40:47 PM »
If the universe is infinite, why is the night sky dark? given infinite space, every line of sight would end with a star - why would there be so much black?

That's Olbers' paradox.  It doesn't apply in this Universe because time doesn't go back to infinity.

So you believe that the universe is infinite in space but has existed for a finite amount of time. Was it infinite in size from the instant it came into being?

BeRational

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Re: Information & knowledge
« Reply #56 on: July 21, 2015, 10:54:54 PM »
I also understood that some galaxies are moving away from us faster than the speed of light so they are lost to us forever
I see gullible people, everywhere!

jeremyp

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Re: Information & knowledge
« Reply #57 on: July 22, 2015, 07:54:19 AM »


So you believe that the universe is infinite in space but has existed for a finite amount of time. Was it infinite in size from the instant it came into being?

I don't think anybody knows the answer to that question.  The BBC poster Speaker to Animals once explained current thinking (as of 10 years ago) to me (she was a physicist) but I can't pretend I understood it.

Certainly, all the stars in the Universe began shinning a finite time ago which is why the sky still looks dark. 
« Last Edit: July 22, 2015, 07:58:57 AM by jeremyp »
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cyberman

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Re: Information & knowledge
« Reply #58 on: July 22, 2015, 07:57:23 PM »


So you believe that the universe is infinite in space but has existed for a finite amount of time. Was it infinite in size from the instant it came into being?

I don't think anybody knows the answer to that question. 

But you believe it anyway. Believing in things which no-one really knows about, Jeremy? Join the club! We have a buffet on Wednesdays.

jeremyp

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Re: Information & knowledge
« Reply #59 on: July 22, 2015, 08:40:27 PM »


So you believe that the universe is infinite in space but has existed for a finite amount of time. Was it infinite in size from the instant it came into being?

I don't think anybody knows the answer to that question. 

But you believe it anyway. Believing in things which no-one really knows about, Jeremy? Join the club! We have a buffet on Wednesdays.

From what we observe of the Universe, it looks like it is infinite in extent.

https://en.wikipedia.org/wiki/Metric_expansion_of_space#Topology_of_expanding_space
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cyberman

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Re: Information & knowledge
« Reply #60 on: July 23, 2015, 12:32:50 AM »


So you believe that the universe is infinite in space but has existed for a finite amount of time. Was it infinite in size from the instant it came into being?

I don't think anybody knows the answer to that question. 

But you believe it anyway. Believing in things which no-one really knows about, Jeremy? Join the club! We have a buffet on Wednesdays.

From what we observe of the Universe, it looks like it is infinite in extent.

https://en.wikipedia.org/wiki/Metric_expansion_of_space#Topology_of_expanding_space

No, it looks finite - but you've got an untested faster-than-light-travel hypothesis to explain why an infinite universe might look finite.

jeremyp

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Re: Information & knowledge
« Reply #61 on: July 23, 2015, 09:48:14 AM »

No, it looks finite - but you've got an untested faster-than-light-travel hypothesis to explain why an infinite universe might look finite.

What observations make you think the Universe is finite?

The observations that make me think the Universe is probably infinite are that space-time is approximately flat as deduced by observations about its expansion.  That doesn't men the Universe is infinite - it might bend back on itself like a torus, but if it does that, it is considerably larger than what we can observe.
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cyberman

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Re: Information & knowledge
« Reply #62 on: July 23, 2015, 09:56:05 AM »

No, it looks finite - but you've got an untested faster-than-light-travel hypothesis to explain why an infinite universe might look finite.

What observations make you think the Universe is finite?

The observations that make me think the Universe is probably infinite are that space-time is approximately flat as deduced by observations about its expansion.  That doesn't men the Universe is infinite - it might bend back on itself like a torus, but if it does that, it is considerably larger than what we can observe.

The observation that the sky is dark. Which you cannot rebut with any counter-observations, but only with an unevidenced guess about things being able to travel faster than light.

And, as you say, the observations you do have are perfectly consistent with "very big" rather than infinite, and very big is consistent with other observations and with your own observation that the universe is finite in time. 

jeremyp

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Re: Information & knowledge
« Reply #63 on: July 23, 2015, 10:03:56 AM »

The observation that the sky is dark.


We've already talked about that and I've already refuted it. 

Quote
Which you cannot rebut with any counter-observations, but only with an unevidenced guess about things being able to travel faster than light.

I have rebutted it.  The Universe is not infinite in the time dimension.  It began a finite time ago, but that doesn't mean it is not infinite in the space direction.

Now do you have any observations that haven't alrewady been rebutted.

While you're doing so, have a read of this

http://www.esa.int/Our_Activities/Space_Science/People/Is_the_Universe_finite_or_infinite_An_interview_with_Joseph_Silk

and perhaps ask yourself why a top scientist doesn't agree with you that "the sky is dark" means the Universe is finite. 
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cyberman

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Re: Information & knowledge
« Reply #64 on: July 23, 2015, 10:16:11 AM »

The observation that the sky is dark.


We've already talked about that and I've already refuted it. 

Quote
Which you cannot rebut with any counter-observations, but only with an unevidenced guess about things being able to travel faster than light.

I have rebutted it.  The Universe is not infinite in the time dimension.  It began a finite time ago, but that doesn't mean it is not infinite in the space direction.

Now do you have any observations that haven't alrewady been rebutted.

While you're doing so, have a read of this

http://www.esa.int/Our_Activities/Space_Science/People/Is_the_Universe_finite_or_infinite_An_interview_with_Joseph_Silk

and perhaps ask yourself why a top scientist doesn't agree with you that "the sky is dark" means the Universe is finite.

I have asked you before - and you have failed to answer - about your idea of an infinite universe existing for a finite period of time. Was it infinitely big from the moment it began? Is that notion consistent with observations of the Big Bang? If it wasn't, how can a finite universe suddenly become infinite, and when do you imagine this happened?

And, really? Are we going with "a 'top' scientist agrees with me so I must be right"...?

Andy

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Re: Information & knowledge
« Reply #65 on: July 23, 2015, 10:52:38 AM »
The observation that the sky is dark. Which you cannot rebut with any counter-observations, but only with an unevidenced guess about things being able to travel faster than light.

Light speed is the limitation to things with mass that exist in space-time. That doesn't account for space-time itself. If you accept that the BB model along with inflation is currently the best explanation we have, then by that definition, you also have to accept that space-time expands "faster" than light speed.

cyberman

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Re: Information & knowledge
« Reply #66 on: July 23, 2015, 12:40:42 PM »
The observation that the sky is dark. Which you cannot rebut with any counter-observations, but only with an unevidenced guess about things being able to travel faster than light.

Light speed is the limitation to things with mass that exist in space-time. That doesn't account for space-time itself. If you accept that the BB model along with inflation is currently the best explanation we have, then by that definition, you also have to accept that space-time expands "faster" than light speed.

The model which was suggested says that objects (such as distant stars) are travelling away from us at faster than the speed of light. That is to say, things with mass that exist in space-time.

Andy

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Re: Information & knowledge
« Reply #67 on: July 23, 2015, 12:45:30 PM »
The observation that the sky is dark. Which you cannot rebut with any counter-observations, but only with an unevidenced guess about things being able to travel faster than light.

Light speed is the limitation to things with mass that exist in space-time. That doesn't account for space-time itself. If you accept that the BB model along with inflation is currently the best explanation we have, then by that definition, you also have to accept that space-time expands "faster" than light speed.

The model which was suggested says that objects (such as distant stars) are travelling away from us at faster than the speed of light. That is to say, things with mass that exist in space-time.

It's not the objects that are moving away, but the space between them that is expanding.

cyberman

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Re: Information & knowledge
« Reply #68 on: July 23, 2015, 12:56:35 PM »
The observation that the sky is dark. Which you cannot rebut with any counter-observations, but only with an unevidenced guess about things being able to travel faster than light.

Light speed is the limitation to things with mass that exist in space-time. That doesn't account for space-time itself. If you accept that the BB model along with inflation is currently the best explanation we have, then by that definition, you also have to accept that space-time expands "faster" than light speed.

The model which was suggested says that objects (such as distant stars) are travelling away from us at faster than the speed of light. That is to say, things with mass that exist in space-time.

It's not the objects that are moving away, but the space between them that is expanding.

If an object is x km away from me, and then later is is 2x km away from me, then it has moved away.

Outrider

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Re: Information & knowledge
« Reply #69 on: July 23, 2015, 01:09:50 PM »
what is its usefulness?

It gives us information on the nature of Pluto's historical development, its interaction with other objects in the far reaches of the Solar System, this allows us to improve our model of the mechanics of the universe.

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We live in an age of information ..... more and more information without really having any better understanding of the universe and our lives.

We live in an age of data, that data can be interpreted into information with the insight, will and time. If you lack the insight or the will, or don't put the time in, it will remain meaningless data.

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The original motivation for space exploration was about doing better than the Soviet Union and a little later it was about finding other places to colonize if the earth becomes uninhabitable.

For some people - particularly those agreeing the funding - it was about the race between the Soviet Union and the West. For many - perhaps most - of the people actually involved in the work it was about exploring the frontiers of knowledge, science, technology and human experience.

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Now we know that we cannot possibly colonize any other planet in the solar system let alone other exoplanets. We now realize (I hope) that we are rooted to the earth and better look after it well if we want to continue to exist. Moving to other planets and exoplanets is out of the question.

... because reasons? Colonising other bodies in the solar system is far from beyond the question, and although the pressure would have to be extreme to consider the costs of extra-solar colonisation it's not beyond the realms of possibility, though it would be stretching current technology.

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One point is that all information is not necessarily knowledge. By knowledge I mean something that helps us grow intellectually and is also useful to us in our lives.  Knowledge should be  about forming a big picture view of life in general by adding relevant information wherever necessary.....and our lives should figure in it in some way....IMO.  Random information can be more of a clutter.

Agreed. I believe information theorist make this the differentiation between data (raw information, if you will) and information (interpreted data that, therefore, has a meaning).

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Secondly, people  can get addicted to information. Some people can actually start believing that all information is knowledge and derive pleasure from acquiring such information.  Intellectual need is also just a need like hunger, sleep or sex. It is possible to get addicted to the pleasurable sensation we experience when we satisfy these needs.

An overstretch of the word 'addiction' - as it is when it's used in realtion to 'sex'. There is no 'addiction' to hunger, there can be a similar habit-forming behaviour with food.

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The same thing can happen to the intellectual need also. Many people  could begin to think that information is an end in itself...at any cost. This is questionable.

And what's the down-side? Part of the definition of addiction is that the desire is harmful - where is the harm in learning?

O.
Universes are forever, not just for creation...

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Andy

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Re: Information & knowledge
« Reply #70 on: July 23, 2015, 01:11:56 PM »
If an object is x km is away from you but is glued to a travelator, then later on it is 2x km away from you, what has done the moving?

You seem to be stuck on the concept that the rate space-time expands is limited to light speed, like the speed of a travelator is limited to how fast you can run along it, or the rate at which you can inflate a balloon is limited to how fast an ant can walk across the surface.

Outrider

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Re: Information & knowledge
« Reply #71 on: July 23, 2015, 01:16:05 PM »
So you believe that the universe is infinite in space but has existed for a finite amount of time. Was it infinite in size from the instant it came into being?

The universe is finite - the dimension in which we measure it came into existence with its creation -  but the "space" into which it's expanding may well be infinite; we have no reliable information on that with which to make a determination.

O.
Universes are forever, not just for creation...

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Enki

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Re: Information & knowledge
« Reply #72 on: July 23, 2015, 02:23:07 PM »
Hi Outrider,

Good post! (Mess 69). And may I say, welcome back. :)

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cyberman

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Re: Information & knowledge
« Reply #73 on: July 23, 2015, 03:13:18 PM »
If an object is x km is away from you but is glued to a travelator, then later on it is 2x km away from you, what has done the moving?



An object with mass in space-time has done the moving

Outrider

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Re: Information & knowledge
« Reply #74 on: July 23, 2015, 03:18:44 PM »
If an object is x km is away from you but is glued to a travelator, then later on it is 2x km away from you, what has done the moving?



An object with mass in space-time has done the moving

Movement, in the absence of an inertial frame of reference, is relative. It rather depends on which point in space you consider to be the reference point - you, the travelator or the object could have moved.

This is ignoring the slight expansion of the intervening space that's likely to have happened, according to current inflationary models.

O.
Universes are forever, not just for creation...

New Atheism - because, apparently, there's a use-by date on unanswered questions.

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