Other founders of the "Golden Age" of Sicience Fiction

[HarryT]

Originally Posted by barryem

I'm no scientist but for me it's hard to imagine how "hard to imagine" equals "impossible". I'm sure flashlights were hard to imagine a couple of centuries ago.

Why are you sure of that? Lanterns have existed for thousands of years - probably ever since the discovery of how to make fire. A flashlight is simply a form of lantern.

[fjtorres]

Originally Posted by HarryT

Why are you sure of that? Lanterns have existed for thousands of years - probably ever since the discovery of how to make fire. A flashlight is simply a form of lantern.

I think he's referring to the idea of electricity generating light. That originated in the 18th century or thereabouts.

[Greg Anos]

Originally Posted by rkomar

I'm a fan of sci-fi, and I'm fine with it using fantasy physics. I did claim that if you were using fantasy physics then you shouldn't worry about hand-waving. Of course, that moved into "We don't know everything, therefore anything is possible", to which I replied: "We don't know everything, but there are things we know not to be possible".

Physicists themselves play with fantasy physics, much of it inspired by sci-fi. They are always trying to find out if what we "know" is wrong, so they try to push outside the realm of what we presently understand to be true. It's legitimate science, but these fantasies need to be demonstrated before we lose confidence in the classic core theories. The existence of research in these areas does not mean that they have a good chance of being validated if we just work hard enough at it. Finding dead ends is normal in the scientific process. So, pointing to current research is not proof that it is possible, let alone imminent.

That said, I think that stories are as important in our lives as science, and I don't want anything to get in the way of good stories. I'm not trying to be a wet blanket and claim that there is no difference between most science fiction and fantasy. I'm just quibbling over what exactly hard sci-fi is.

Possible and impossible are base upon assumptions, rarely voiced. Something that may be considered impossible, is only impossible because we don't consider the possibility of being able to change the underlying assumptions. And vice versa.

Let me give a (relatively) non-controversial example. Can a reactionless drive exist?

Yes.

How? If we could control gravity, you would have a reactionless drive. Artificially distort space-time either in front or behind your craft, by the application of some form of energy only, creating a potential energy gradient, which then gets converted in to kinetic energy.

Do we have a clue how to do this? Absolutely not! But there is nothing in physics that precludes it.

[rkomar]

Originally Posted by Ralph Sir Edward

Possible and impossible are base upon assumptions, rarely voiced. Something that may be considered impossible, is only impossible because we don't consider the possibility of being able to change the underlying assumptions. And vice versa.

When researching the "impossible" in physics, it is usual to break down the theory to its base assumptions so that you know what you are really testing. So I would not say the assumptions are "rarely voiced"; they are front and center to the whole process of research in pure physics (as opposed to applied physics).

[Greg Anos]

Originally Posted by rkomar

When researching the "impossible" in physics, it is usual to break down the theory to its base assumptions so that you know what you are really testing. So I would not say the assumptions are "rarely voiced"; they are front and center to the whole process of research in pure physics (as opposed to applied physics).

<shrug> One man's theory is another man's application, and vice versa.

What are the unacknowledged assumptions behind c as the maximum speed of light, for example?

[rkomar]

Originally Posted by Ralph Sir Edward

<shrug> One man's theory is another man's application, and vice versa.

What are the unacknowledged assumptions behind c as the maximum speed of light, for example?

The assumption that if, no matter how hard you try, nothing you see ever goes faster than the speed of light, then that's the maximum. And that's still the case, over 100 years after Einstein came up with special relativity to describe what they saw before that. There are many ways we create stuff that gets up to or near the speed of light, without going over. Included in that are particles in accelerators, that just keep getting heavier as you add energy rather than go faster than the speed of light, in agreement with special relativity. The universe is a big place with all kinds of stupendously energetic processes taking place in it. If none of them produce anything that moves faster than the speed of light, you have to start thinking that that's the limit. It's not just a matter of no imagination.

[Greg Anos]

Originally Posted by rkomar

The assumption that if, no matter how hard you try, nothing you see ever goes faster than the speed of light, then that's the maximum. And that's still the case, over 100 years after Einstein came up with special relativity to describe what they saw before that. There are many ways we create stuff that gets up to or near the speed of light, without going over. Included in that are particles in accelerators, that just keep getting heavier as you add energy rather than go faster than the speed of light, in agreement with special relativity. The universe is a big place with all kinds of stupendously energetic processes taking place in it. If none of them produce anything that moves faster than the speed of light, you have to start thinking that that's the limit. It's not just a matter of no imagination.

But why is c (the speed of light as measured in a vacuum) the boundary limit. That is a more interesting question. . .

The question is not whether or not one can travel faster than the speed of light, but why is the speed of light limited to c? A more interesting question, that gets to the underlying assumptions. . .

[barryem]

Originally Posted by rkomar

Sure, but nothing we have accomplished so far goes against the laws of physics.

A lot of what we've already accomplished far exceeds what was previously known. If you wrote a science fiction novel 200 years ago with a Zippo cigarette lighter or a flashlight it would have been labeled "fantasy". If you'd included a cell phone it would have been labeled "comedy".

Barry

[barryem]

Originally Posted by fjtorres

I think he's referring to the idea of electricity generating light. That originated in the 18th century or thereabouts.

I was thinking of electricity and also the portability made possible by batteries.

I think flashlights are enough different from lanterns and torches that there shouldn't be much confusion. They accomplish the same thing in very different ways. We're sticklers for the differences in front lights and back lights. Why not flashlights and lanterns, which have even less in common.

Barry

[Thasaidon]

Originally Posted by barryem

A lot of what we've already accomplished far exceeds what was previously known. If you wrote a science fiction novel 200 years ago with a Zippo cigarette lighter or a flashlight it would have been labeled "fantasy". If you'd included a cell phone it would have been labeled "comedy".

Barry

Or Infernal comedy

I say cell phones are the invention of the Devil, an abomination unto the Lord!

[AnotherCat]

Originally Posted by rkomar

The assumption that if, no matter how hard you try, nothing you see ever goes faster than the speed of light, then that's the maximum. And that's still the case, over 100 years after Einstein came up with special relativity to describe what they saw before that...

That is the current belief for cases where special relativity applies i.e. locally over small distances where one can approximate spacetime to being flat. However, general relativity which applies over large distances, where the curvature of spacetime must be taken into account, does not prohibit speeds faster than that of light.

An example is, if the current model of the universe's expansion is correct, that galaxies sufficiently far away from us are traveling at speeds greater than that of light. Furthermore, despite their speed being faster than that of light, we can still see some of them.

Regardless, I think it is unlikely that current models/theories/laws will survive unchanged so I have an open mind. They are mathematically and observationally correct at this time, but history tells us that they are probably going to get modified with time.

[rkomar]

Originally Posted by AnotherCat

That is the current belief for cases where special relativity applies i.e. locally over small distances where one can approximate spacetime to being flat. However, general relativity which applies over large distances, where the curvature of spacetime must be taken into account, does not prohibit speeds faster than that of light.

An example is, if the current model of the universe's expansion is correct, that galaxies sufficiently far away from us are traveling at speeds greater than that of light. Furthermore, despite their speed being faster than that of light, we can still see some of them.

Regardless, I think it is unlikely that current models/theories/laws will survive unchanged so I have an open mind. They are mathematically and observationally correct at this time, but history tells us that they are probably going to get modified with time.

I've been arguing this in terms of the faster-than-light communication required in much of science fiction. If cosmic space is stretching to make galaxies speed apart at even greater speeds, I don't see how that makes faster-than-light communication any more possible.

I agree that we still have much to learn, but I still don't agree that anything we learn is going to make the basics we know completely wrong. It would also have to make everything we see completely wrong, as well. That's the part I have trouble coming to terms with. How do you who think we could be wrong explain how these mistakes don't manifest themselves in what we see of the universe? Does the speed of light hold in all cases except in some few that conveniently explain some macguffins used in some sci-fi novels?

[rkomar]

Originally Posted by Ralph Sir Edward

But why is c (the speed of light as measured in a vacuum) the boundary limit. That is a more interesting question. . .

The question is not whether or not one can travel faster than the speed of light, but why is the speed of light limited to c? A more interesting question, that gets to the underlying assumptions. . .

That's a very good question that lies outside my knowledge to even attempt to answer. I know that it has been considered in physics in that last few decades, but I've been out of it for over 15 years, and am ignorant of any recent progress on that front. Maybe someone else can answer you, but it ain't me.

[AnotherCat]

Originally Posted by rkomar

I've been arguing this in terms of the faster-than-light communication required in much of science fiction. If cosmic space is stretching to make galaxies speed apart at even greater speeds, I don't see how that makes faster-than-light communication any more possible.

I agree that we still have much to learn, but I still don't agree that anything we learn is going to make the basics we know completely wrong. It would also have to make everything we see completely wrong, as well. That's the part I have trouble coming to terms with. How do you who think we could be wrong explain how these mistakes don't manifest themselves in what we see of the universe? Does the speed of light hold in all cases except in some few that conveniently explain some macguffins used in some sci-fi novels?

Your not seeing how that makes faster-than-light communication any more possible is not a theory at all, but just an opinion based on your own interpretation. Your not seeing it does not preclude it happening.

Your How do you who think we could be wrong explain how these mistakes don't manifest themselves in what we see of the universe? seems to ignore that around 95% of the universe is not understood, that not just due to minor omissions from knowledge but pretty much just not understood as to how and why at all. {EDIT: it is also possible that there may be more than that of the universe that is not understood, it was only a short time ago that we did not know about the "missing" 95% and nobody much expected anything was missing from the models, perhaps there is more yet to become apparent to us}

As I said, I have an open mind on these things and without being silly about it history tells us that the theories/models/laws of physics are open to change over the course of time. It seems foolish to me to align oneself to a belief that current knowledge is immutable. As you probably know, there are stated opinions among well regarded physicists and cosmologists that to understand things seeming to become apparent to us about the energy and mass structure of the universe that it may be that special and, more particularly, general relativity may change in some way yet unknown.

I'll leave it at that as I cannot see any argument that I can produce will change any unswerving belief of others that the physics as it is now will not change in any substantive way into the future.

[HarryT]

Originally Posted by barryem

I was thinking of electricity and also the portability made possible by batteries.

Both electricity and batteries were well known a couple of centuries ago: the first electric telegraph, for example, was invented in 1816. Hence my disagreement with your comment that a flashlight would have been "hard to imagine".