Thread: Scifi impossibilities

I have always enjoyed science fiction. But one of the things that disturbs a good skeptic like me is the number of elements in science fiction books that I am pretty sure are utterly impossible. In other words, they are not a fictional science, but magic.

I am happy to accept something that we cannot achieve today, but which might be possible, such as suspended animation. But what of all those things which, according to our appreciation of the lawsd of physics, are utterly and totally impossible? I can think of a few.

1. Faster than light travel. (Or radio).
2. Tractor beams.
3. Energy fields as armour.
4. Inertial compensators.
5. Time travel into the past.
6. Psychic powers.

And so on.

I guess an author has the right to adopt one or two of them as 'artistic license' and pretend that some time in the future humanity might have a breakthrough that permits an action currently considered impossible. But how far should an author go in this? How blatant can the author be? Is this not an affront to credibility? At what point does a scifi book become fantasy?

7. Artificial gravity
8. Universal translators

To dan

Well thought out. I agree.

Originally Posted by danhanegan

8. Universal translators

We're getting close to that now. I have a phone which can listen to a language and give me the text of what people are saying in English.

1. Faster than light travel. (Or radio).

Entanglement presents a potential method of faster than light radio. So far no successes, but physicists are running experiments which might at least theoretically succeed. (Google Dopfer and Cramer)

2. Tractor beams.

Well, tractor beams are again possible in theory at least with metallic objects.

4. Inertial compensators.

These aren't impossible at all, just impractical.

5. Time travel into the past.

Again, possible, just very, very hard to even experiment with. Google "Godel Metric."

9. Hot, green, metallic bikini wearing aliens that you want to "Kirk".

Chances are, if we do find other intelligent life in the galaxy, they will be completely different from us, and certainly not something you'd want to put your "phaser" into.

Billvon

The universal translater that we find impossible is the Star Trek variety that instantly lets you talk to a new alien species. Not one that has been painstakingly programmed for known languages.

Faster than light is still impossible. Every few years some physicist comes up with a new suggestion for FTL, but another physicist soon finds the flaw. It appears that the universe itself has "decided" to ban FTL, and stops all loopholes. That includes entanglement. This is not something I am expert at, but my reading tells me that even sending information at FTL speeds via entanglement is not possible.

Tractor beams and inertial compensators as shown in Star Trek and elsewhere are also impossible according to the laws of physics. And so on.

Originally Posted by skeptic

Faster than light is still impossible.

These certitudes should end with 'now' or 'today' or 'according to the known laws of science'. These 'impossibilities' of today may become the realities of tomorrow.

Originally Posted by skeptic

The universal translater that we find impossible is the Star Trek variety that instantly lets you talk to a new alien species. Not one that has been painstakingly programmed for known languages.

Right, it's a much harder problem to solve. But not impossible. (Needless to say the Star Trek "paradigm" seems to be that all xenosapients just plain speak English, which is even more unlikely.)

Faster than light is still impossible. Every few years some physicist comes up with a new suggestion for FTL, but another physicist soon finds the flaw. It appears that the universe itself has "decided" to ban FTL, and stops all loopholes. That includes entanglement. This is not something I am expert at, but my reading tells me that even sending information at FTL speeds via entanglement is not possible.

Well, there is currently nothing _stopping_ it, which is what's so interesting about it.

Tractor beams and inertial compensators as shown in Star Trek and elsewhere are also impossible according to the laws of physics. And so on.

Tractor beam - magnetic fields will do that now, and indeed magnetic levitation is commonly used in industry and transportation. Impractical at a distance but not impossible.
Inertial compensators - put a massive body in front of a person (say Earth sized) and accelerate at 2G's and the person will feel only 1G. Impractical but not impossible.

10. Immortality

11. Creating a new sun

It is never a good idea to state that the laws of physics, as we know them today, cannot change sometime in the future. This mistake has been made by reputable scientists:

There is nothing new to be discovered in physics now. All that remains is more and more precise measurement.

This has been attributed to William Thomson, Lord Kelvin (1824–1907) in an address to the British Association for the Advancement of Science in 1900.

It seems probable that most of the grand underlying principles have now been firmly established and that further advances are to be sought chiefly in the rigorous application of these principles to all the phenomena which come under our notice…. An eminent physicist has remarked that the future truths of physical science are to be looked for in the sixth place of decimals.

A similar comment made by the German-American scientist Albert Michelson (1852–1931) in 1894.

(Note that both proclamations were made before Relativity and Quantum Mechanics.)

Chuck

I am aware of the philosophy that nothing is impossible. I just disagree with it. There are many things declared impossible which came to be anyway. But none of them violated the laws of physics. The ones I listed violate those laws. FTL violates the laws of physics. Tractor beams, of the sort shown in Star Trek violate those laws. (Electromagnetism is something else).

I do have to point out to cosmictraveller, though, that there is no such ban on immortality, if we define immortality as never growing old. Obviously, immortality and invulnerability together are something else, and I think that would be impossible.

Originally Posted by skeptic

The ones I listed violate those laws. FTL violates the laws of physics. Tractor beams, of the sort shown in Star Trek violate those laws.

Sure. I agree that those things violate the laws of physics today. But if you had proposed a "twins paradox" to readers of the late 1890s, people, just like you and I, might say, "Hey, that violates the rules of physics as we know them today." (circa 1895). But now we know that Einstein's Special Theory of Relativity shows that this "twins paradox" is actually something that can occur. It has even been proven quite a few times using atomic clocks. Do I personally believe that FTL and time travel are possible? No, I don't. But my opinion isn't worth much -- maybe nothing.

It's not to say I don't like this thread. I love science fiction too -- been reading it since I was a child. This is a good thread. Thanks for starting it.

I like to read "hard" science fiction. My favorite author is probably Arthur C. Clarke. Although Clarke deviates into "softer" science fiction sometimes.

(If anyone can recommend good modern hard SF writers, please do -- but maybe in a PM so we don't go off topic here.)

Depends on how well it's written.
Peter F. Hamilton and Ian M. Banks - to give two examples - write "impossible" SF, but Hamilton especially writes stuff I wouldn't be without.

Originally Posted by Dywyddyr

Depends on how well it's written.

I've lost a fair amount of money over the years buying SF paperbacks only to throw them into the GoodWill box after the first 10-20 pages. When I was younger I felt "compelled" to finish any book that I bought. Not any more.

Originally Posted by skeptic

The ones I listed violate those laws. FTL violates the laws of physics. Tractor beams, of the sort shown in Star Trek violate those laws. (Electromagnetism is something else)

That's like a person 110 years ago saying "there will never be flying machines that fly across the ocean, transporting people and goods at high speeds. The Wright Flyer is something else."

Originally Posted by Chucknorium

(If anyone can recommend good modern hard SF writers, please do -- but maybe in a PM so we don't go off topic here.)

Robert Forward is perhaps the "hardest of the hard" sci fi authors. All his books are based pretty firmly on either his own research into physics or other cutting edge research.

12. Radars detecting lazer beams. Dodging lazers is especially nonsensical. Nothing travels faster than light, so unless you are just looking at the barrel and guessing, the only way to detect the lazer would be to get hit by it.

Dywyddyr, billvon,

Thanks for the book recommendations. I will check them out.

Originally Posted by SowZ37

Dodging lazers is especially nonsensical. Nothing travels faster than light, so unless you are just looking at the barrel and guessing, the only way to detect the lazer would be to get hit by it.

Yeah, every time I see some guy dodge a hand-held phaser blast in Star Trek, I say to the screen, "Hey, someone give me a .45! This POS is worthless."

Originally Posted by Chucknorium

Dywyddyr, billvon,

Thanks for the book recommendations. I will check them out.

Originally Posted by SowZ37

Dodging lazers is especially nonsensical. Nothing travels faster than light, so unless you are just looking at the barrel and guessing, the only way to detect the lazer would be to get hit by it.

Yeah, every time I see some guy dodge a hand-held phaser blast in Star Trek, I say to the screen, "Hey, someone give me a .45! This POS is worthless."

Even worse, after they miss, they just adjust the setting to a wide beam or something and hit no problem. Why didn't you have it on the better setting in the first place?!?

.....

Originally Posted by SowZ37

Originally Posted by Chucknorium

Originally Posted by SowZ37

Dodging lazers is especially nonsensical. Nothing travels faster than light, so unless you are just looking at the barrel and guessing, the only way to detect the lazer would be to get hit by it.

Yeah, every time I see some guy dodge a hand-held phaser blast in Star Trek, I say to the screen, "Hey, someone give me a .45! This POS is worthless."

Even worse, after they miss, they just adjust the setting to a wide beam or something and hit no problem. Why didn't you have it on the better setting in the first place?!?

I love STNG. I can watch the original but I can't watch any of the later series. But as much as I love STNG, I still love to poke fun of it.

Originally Posted by Chucknorium

Originally Posted by SowZ37

Originally Posted by Chucknorium

Originally Posted by SowZ37

Dodging lazers is especially nonsensical. Nothing travels faster than light, so unless you are just looking at the barrel and guessing, the only way to detect the lazer would be to get hit by it.

Yeah, every time I see some guy dodge a hand-held phaser blast in Star Trek, I say to the screen, "Hey, someone give me a .45! This POS is worthless."

Even worse, after they miss, they just adjust the setting to a wide beam or something and hit no problem. Why didn't you have it on the better setting in the first place?!?

I love STNG. I can watch the original but I can't watch any of the later series. But as much as I love STNG, I still love to poke fun of it.

Same here.

9. Thousand year cryogenic slumbers
10. Brain transplants, or moving consciousness between two of them
11. Transporters

To Lynx

I agree they are seriously unlikely, but not necessarily impossible.

Cryogenic slumbers.
The biggest problem here is resurrecting someone from such a slumber. But if it were possible to totally freeze someone for even a day, and then successfully resurrect them, it really would not matter if the frozen state lasted a day, or a year, or a million years.

Moving consciousness.
I think that a person who has his/her consciousness moved in that way would actually end up dead. But it might be possible to clone a consciousness, so that a close imitation would then exist in another site.

Transporters.
Interestingly, this may not be impossible. Using quantum entanglement methods, it is now possible to transport something of quantum size, like a photon or an atom, from one place to another. Admittedly, it would be many orders of magnitude more difficult to transport a whole human body, but there is nothing in the laws of physics to prophibit it.

NP

NP

The ones I listed violate those laws.

What law of physics exists that prevents time travel into the past?
If your answer is paradoxes, there are several proposed conjectures that would solve all possible paradoxes.

NP

Originally Posted by anticorncob28

The ones I listed violate those laws.

What law of physics exists that prevents time travel into the past?
If your answer is paradoxes, there are several proposed conjectures that would solve all possible paradoxes.

It is not so much that a law prohibits such travel. It is more that there is no way, even in theory, where it might be possible. It is like FTL, where many physicists have tried hard to find a way, and each time, the universe hit back and showed that the method suggested would not work.

Originally Posted by skeptic

To Lynx

I agree they are seriously unlikely, but not necessarily impossible.

Cryogenic slumbers.
The biggest problem here is resurrecting someone from such a slumber. But if it were possible to totally freeze someone for even a day, and then successfully resurrect them, it really would not matter if the frozen state lasted a day, or a year, or a million years.

I totally agree but represented it as often depicted in Scifi, where folks are frozen for long long periods.

Moving consciousness.
I think that a person who has his/her consciousness moved in that way would actually end up dead. But it might be possible to clone a consciousness, so that a close imitation would then exist in another site.

Given the complexity of the brain, from not only the macroscale cells but down to the important much smaller forces such as Van der Waals at the atomic level essential to its functioning, chaos theory completely rules out copying an replica of the information-It is completely impossible.

Originally Posted by skeptic

To Lynx

I agree they are seriously unlikely, but not necessarily impossible.

Cryogenic slumbers.
The biggest problem here is resurrecting someone from such a slumber. But if it were possible to totally freeze someone for even a day, and then successfully resurrect them, it really would not matter if the frozen state lasted a day, or a year, or a million years.

Moving consciousness.
I think that a person who has his/her consciousness moved in that way would actually end up dead. But it might be possible to clone a consciousness, so that a close imitation would then exist in another site.

Transporters.
Interestingly, this may not be impossible. Using quantum entanglement methods, it is now possible to transport something of quantum size, like a photon or an atom, from one place to another. Admittedly, it would be many orders of magnitude more difficult to transport a whole human body, but there is nothing in the laws of physics to prophibit it.

Not to mention you'd have to freeze them at a low enough temperature not completely destroy capillaries. Then there is that tricky bit about re-animating dead tissue somehow.

Originally Posted by Chucknorium

I like to read "hard" science fiction. My favorite author is probably Arthur C. Clarke. Although Clarke deviates into "softer" science fiction sometimes.

(If anyone can recommend good modern hard SF writers, please do -- but maybe in a PM so we don't go off topic here.)

Agree entirely. Hard sci-fi is written with a few "impossible" premisses, for which the reader has to suspend disbelief but then, with those as givens, the rest fits with it in a scientifically consistent manner. The game is to see what effects then arise. Clarke is a master of course. And Asimov (The Gods Themselves was a favourite) But I also recall reading with great pleasure "Mission of Gravity" by Hal Clement. I don't whether anyone still reads his stuff, but I found it intriguing as a teenager.

So I don't mind the few impossible premisses, as without them you don't have any science fiction in space, which is by far the most exciting setting, of course. What I hate, though, is carelessly ridiculous effects in films (sound in explosions and billowing clouds of smoke in space from rocket motors etc, views on screens requiring a camera viewpoint that doesn't exist, spiral orbits…). I also hate, above all, perhaps, lazily anthropoid aliens - what a failure of imagination, when it is vanishingly unlikely that alien life would resemble our own.

Originally Posted by exchemist

Originally Posted by Chucknorium

I like to read "hard" science fiction. My favorite author is probably Arthur C. Clarke. Although Clarke deviates into "softer" science fiction sometimes.

(If anyone can recommend good modern hard SF writers, please do -- but maybe in a PM so we don't go off topic here.)

Agree entirely. Hard sci-fi is written with a few "impossible" premisses, for which the reader has to suspend disbelief but then, with those as givens, the rest fits with it in a scientifically consistent manner. The game is to see what effects then arise. Clarke is a master of course. And Asimov (The Gods Themselves was a favourite) But I also recall reading with great pleasure "Mission of Gravity" by Hal Clement. I don't whether anyone still reads his stuff, but I found it intriguing as a teenager.

So I don't mind the few impossible premisses, as without them you don't have any science fiction in space, which is by far the most exciting setting, of course. What I hate, though, is carelessly ridiculous effects in films (sound in explosions and billowing clouds of smoke in space from rocket motors etc, views on screens requiring a camera viewpoint that doesn't exist, spiral orbits…).

Agreed. Thanks for the response! I've read quite a few Azimov novels, including The Gods Themselves. Also good scifi.

I also hate, above all, perhaps, lazily anthropoid aliens - what a failure of imagination, when it is vanishingly unlikely that alien life would resemble our own.

I can understand it on TV and the movies because then it doesn't require any CG so it is usually cheaper -- but maybe that is changing now. Let's hope so.

Originally Posted by exchemist

Originally Posted by Chucknorium

I like to read "hard" science fiction. My favorite author is probably Arthur C. Clarke. Although Clarke deviates into "softer" science fiction sometimes.

(If anyone can recommend good modern hard SF writers, please do -- but maybe in a PM so we don't go off topic here.)

Agree entirely. Hard sci-fi is written with a few "impossible" premisses, for which the reader has to suspend disbelief but then, with those as givens, the rest fits with it in a scientifically consistent manner. The game is to see what effects then arise. Clarke is a master of course. And Asimov (The Gods Themselves was a favourite) But I also recall reading with great pleasure "Mission of Gravity" by Hal Clement. I don't whether anyone still reads his stuff, but I found it intriguing as a teenager.

So I don't mind the few impossible premisses, as without them you don't have any science fiction in space, which is by far the most exciting setting, of course. What I hate, though, is carelessly ridiculous effects in films (sound in explosions and billowing clouds of smoke in space from rocket motors etc, views on screens requiring a camera viewpoint that doesn't exist, spiral orbits…). I also hate, above all, perhaps, lazily anthropoid aliens - what a failure of imagination, when it is vanishingly unlikely that alien life would resemble our own.

But the bipedal organism is the most energy efficient mechanism of land locomotion we know of, hands with opposable thumbs are important to fully utilize high intelligence, and at least two hands is ideal. I'm not so sure that a two legged, two armed alien is unlikely.

Originally Posted by Lynx_Fox

Given the complexity of the brain, from not only the macroscale cells but down to the important much smaller forces such as Van der Waals at the atomic level essential to its functioning, chaos theory completely rules out copying an replica of the information-It is completely impossible.

Agreed that you cannot make an exact copy but you can certainly make a _functionally equivalent_ copy. Consider now how I can run a simulated 8080 processor on a modern processor and the software doesn't even know it's on a modern processor. It is functionally equivalent to an old Altair 8800 - but of course not identical.

Originally Posted by SowZ37

But the bipedal organism is the most energy efficient mechanism of land locomotion we know of

I'd argue that four and six legs are both more efficient and far more common.

hands with opposable thumbs are important to fully utilize high intelligence

?? Why not four equal fingers, all closing towards a midline, moved out of the way when the limb is used for walking?

and at least two hands is ideal.

Well, at least two manipulators is ideal - but again they need not be hands.

Originally Posted by SowZ37

Originally Posted by exchemist

Originally Posted by Chucknorium

I like to read "hard" science fiction. My favorite author is probably Arthur C. Clarke. Although Clarke deviates into "softer" science fiction sometimes.

(If anyone can recommend good modern hard SF writers, please do -- but maybe in a PM so we don't go off topic here.)

Agree entirely. Hard sci-fi is written with a few "impossible" premisses, for which the reader has to suspend disbelief but then, with those as givens, the rest fits with it in a scientifically consistent manner. The game is to see what effects then arise. Clarke is a master of course. And Asimov (The Gods Themselves was a favourite) But I also recall reading with great pleasure "Mission of Gravity" by Hal Clement. I don't whether anyone still reads his stuff, but I found it intriguing as a teenager.

So I don't mind the few impossible premisses, as without them you don't have any science fiction in space, which is by far the most exciting setting, of course. What I hate, though, is carelessly ridiculous effects in films (sound in explosions and billowing clouds of smoke in space from rocket motors etc, views on screens requiring a camera viewpoint that doesn't exist, spiral orbits…). I also hate, above all, perhaps, lazily anthropoid aliens - what a failure of imagination, when it is vanishingly unlikely that alien life would resemble our own.

But the bipedal organism is the most energy efficient mechanism of land locomotion we know of, hands with opposable thumbs are important to fully utilize high intelligence, and at least two hands is ideal. I'm not so sure that a two legged, two armed alien is unlikely.

Hmm. I'd have thought there were enough inefficient things about the human body to make it doubtful that it represents an optimum design. I'm sure the grasping hands provided synergy with an expanding brain capacity, but this could apply to other grasping mechanisms.

Originally Posted by billvon

Originally Posted by SowZ37

But the bipedal organism is the most energy efficient mechanism of land locomotion we know of

I'd argue that four and six legs are both more efficient and far more common.

hands with opposable thumbs are important to fully utilize high intelligence

?? Why not four equal fingers, all closing towards a midline, moved out of the way when the limb is used for walking?

and at least two hands is ideal.

Well, at least two manipulators is ideal - but again they need not be hands.

Nope. The best energy output for input is bipedal. It doesn't have the highest short term speed potential, but is better for energy. It is why humans are the best long distance land animal on the planet. When we migrate, on foot, an in shape human goes farther in a day than anything else and we spend less energy to move a mile than a four legged creature of the same weight would. Four legs has other advantages.

I heard something today, but did not catch the name of the speaker and it did not come up on a quick search but it seems to apply to the topic of this thread.

The facts never change.

It is our understanding of the facts that changes.

Originally Posted by scheherazade

I heard something today, but did not catch the name of the speaker and it did not come up on a quick search but it seems to apply to the topic of this thread.

The facts never change.

It is our understanding of the facts that changes.

Er…...very Delphic….and, superficially at least, wrong-sounding. Facts in general clearly do change, given that the world is not a static system. But perhaps the context of this remark would explain why it was made.

What has this to do with sci-fi impossibilities?

Originally Posted by exchemist

Originally Posted by scheherazade

I heard something today, but did not catch the name of the speaker and it did not come up on a quick search but it seems to apply to the topic of this thread.

The facts never change.

It is our understanding of the facts that changes.

Er…...very Delphic….and, superficially at least, wrong-sounding. Facts in general clearly do change, given that the world is not a static system. But perhaps the context of this remark would explain why it was made.

What has this to do with sci-fi impossibilities?

If I have to explain, we really are NOT going to get it, lol...

As example, the world was never flat, but for a considerable time, we surely thought it was. The facts did not change...

In the context of this thread, we may discover that the laws of physics as we understand them now, are but the tip of the iceberg, so to speak.

Originally Posted by scheherazade

Originally Posted by exchemist

Originally Posted by scheherazade

I heard something today, but did not catch the name of the speaker and it did not come up on a quick search but it seems to apply to the topic of this thread.

The facts never change.

It is our understanding of the facts that changes.

Er…...very Delphic….and, superficially at least, wrong-sounding. Facts in general clearly do change, given that the world is not a static system. But perhaps the context of this remark would explain why it was made.

What has this to do with sci-fi impossibilities?

If I have to explain, we really are NOT going to get it, lol...

As example, the world was never flat, but for a considerable time, we surely thought it was. The facts did not change...

In the context of this thread, we may discover that the laws of physics as we understand them now, are but the tip of the iceberg, so to speak.

Ah OK I understand now. If this person had said REALITY never changes, but our understanding of it does, then I would have comprehended.

The flat earth idea was given up about 300BC, I think.

Originally Posted by skeptic

I have always enjoyed science fiction. But one of the things that disturbs a good skeptic like me is the number of elements in science fiction books that I am pretty sure are utterly impossible. In other words, they are not a fictional science, but magic.

For the simpletons it's magic.

Is there any real expectation of significant "new" physics that would not merely refine and clarify but can overturn what's currently known and result in technologies that are currently considered impossible? Dark matter and acceleration of expansion of the universe are suggestive that there may be some wriggle room, however I do think too much is known with a lot of confidence for there to be a lot of room to fit a complete rewrite of physics that would allow things like anti-gravity or FTL.

Originally Posted by Ken Fabos

Is there any real expectation of significant "new" physics that would not merely refine and clarify but can overturn what's currently known . . . .

I am reminded of a quote attributed to Lord Kelvin made in 1900, a few years before Einstein's Relativity and Quantum Mechanics:

"There is nothing new to be discovered in physics now, All that remains is more and more precise measurement."

Originally Posted by billvon

Originally Posted by danhanegan;565518

[quote

5. Time travel into the past.

Again, possible, just very, very hard to even experiment with. Google "Godel Metric."

How can this be possible? you can't rewind actions like a tape player.

If I were to tell you that I had discovered pretty little fairies, with four wings each, living in the bottom of my garden, you would rightly declare me to be a nut case. If a writer tells you that his characters are buzzing around the universe at some multiple of light speed, using tractor beams and anti-gravity, then that writer is writing about magic. Because there is no way, even in theory, those things can be accomplished. You can speculate all you like about some weird new physics in aother 100 or 200 years. In today's world, those things are magic. A writer who includes magic in his story line is a writer of fantasy, not science fiction.

Originally Posted by skeptic

If I were to tell you that I had discovered pretty little fairies, with four wings each, living in the bottom of my garden, you would rightly declare me to be a nut case. If a writer tells you that his characters are buzzing around the universe at some multiple of light speed, using tractor beams and anti-gravity, then that writer is writing about magic. Because there is no way, even in theory, those things can be accomplished. You can speculate all you like about some weird new physics in another 100 or 200 years. In today's world, those things are magic. A writer who includes magic in his story line is a writer of fantasy, not science fiction.

Not necessarily. Read this. Main/Mohs Scale of Science Fiction Hardness - Television Tropes & Idioms

Another big thing in sort-of-hard-sci-fi is inventing a bunch of laws of physics, and as long as they don't directly conflict with current observable laws of physics, it is still speculative fiction/sci-fi. In the world of speculative fiction, making a new kind of physics that doesn't conflict with current laws isn't magic. Something like Dr. Who or Star Wars is fantasy, sure. Something like Star Trek could qualify as both.

Originally Posted by grmpysmrf

How can this be possible? you can't rewind actions like a tape player.

Correct - but you can move into a universe where those actions haven't happened yet.

Originally Posted by billvon

Originally Posted by grmpysmrf

How can this be possible? you can't rewind actions like a tape player.

Correct - but you can move into a universe where those actions haven't happened yet.

The multiverse theory?

Multiverse Controversy Heats Up over Gravitational Waves - Scientific American

The multiverse idea is a lot more likely than FTL travel. There are no laws of physics to prohibit it, and some phenomena are easier to explain if we assume a multiverse. Of course, writing a story in which the characters move from one universe to another is still fantasy, since there is no way, even in theory, of doing this without being destroyed.

There are degrees of impossible. It is correct that Star Trek is less fantasy than Star Wars, but it is still fantasy. It still relies on ideas that have to be classified as magic, rather than science.

Originally Posted by Chucknorium

Originally Posted by Ken Fabos

Is there any real expectation of significant "new" physics that would not merely refine and clarify but can overturn what's currently known . . . .

I am reminded of a quote attributed to Lord Kelvin made in 1900, a few years before Einstein's Relativity and Quantum Mechanics:

"There is nothing new to be discovered in physics now, All that remains is more and more precise measurement."

I think there is a lot more known with high levels of confidence and a lot less room for new physics that overturns what is known than in 1900.

Originally Posted by skeptic

I have always enjoyed science fiction. But one of the things that disturbs a good skeptic like me is the number of elements in science fiction books that I am pretty sure are utterly impossible. In other words, they are not a fictional science, but magic.

I am happy to accept something that we cannot achieve today, but which might be possible, such as suspended animation. But what of all those things which, according to our appreciation of the lawsd of physics, are utterly and totally impossible? I can think of a few.

1. Faster than light travel. (Or radio).
2. Tractor beams.
3. Energy fields as armour.
4. Inertial compensators.
5. Time travel into the past.
6. Psychic powers.

And so on.

I guess an author has the right to adopt one or two of them as 'artistic license' and pretend that some time in the future humanity might have a breakthrough that permits an action currently considered impossible. But how far should an author go in this? How blatant can the author be? Is this not an affront to credibility? At what point does a scifi book become fantasy?

Well, there are several different categories of SF literature. Some SF, which is considered "soft," uses science fiction tropes to explore the human condition in new and exciting ways (e.g., a story about two lovers, one of whom lives aboard a fast spaceship affected by time dilation). The science may not be plausible, but that's not the author's intention. Another kind of SF is so-called "hard" SF, and its authors try to keep the science--at least the science that's relevant to the plot--as realistic as possible (e.g., a novel about terraforming that uses plausible science to discuss the terraforming, even though the characters reached the planet via "hyper-drive" or whatever). There are also many sub-categories, which I'm too lazy to get into.

I think there will be limits to scientific understanding and technological advancement - and we are closer to them now than a century ago. And we are better able to determine where those limits are likely to be than a century ago; there will be surprises, but as our understanding of the physical universe keeps being refined there will be progressively less of them.