[RD] Will we ever travel faster than light speed?

[Lemon Merchant]

Why is this in the Off Topic section?

Because it is indeed an off topic type thread.

I don't think we'll ever see FTL. At the very least it will be a long time away. The amount of energy required to accelerate even a small amount of mass to light speed is staggering. Moving a spaceship like that would take a stultifying amount of energy. In my wildest dreams, I couldn't imagine how much energy that would take.

But then there is Clarke's Third Law: Any sufficiently advanced technology is indistinguishable from magic.

 

[MagisterCultuum]

I prefer the contrapositive formulation "Any technology that is distinguishable from magic is insufficiently advanced."

 

[Thorgalaeg]

I don't think we'll ever see FTL. At the very least it will be a long time away. The amount of energy required to accelerate even a small amount of mass to light speed is staggering.

It is not staggering, it is infinite.

Moving through space FTL is not only impossible It does not make sense. It is not only a physical impossibility, but a logical impossibility in relativity terms. It is like going colder than absolute zero, since temperature is particle movement, you can't decelerate something when it is already stopped. (Well, there are esoteric ways to get negative absolute temperature, but paradoxically that does not mean going colder but infinitely hotter)

However we could find ways to go from A to B without having to move through the space between.

 

[Michkov]

Because it is indeed an off topic type thread.

Despite having a Science and Technology subforum right around the corner?

 

[Hygro]

Despite having a Science and Technology subforum right around the corner?

It would be the same posters but over the course of months instead of days.

 

[Narz]

Maybe we'll reach .1% of it.

 

[Cutlass]

I prefer the contrapositive formulation "Any technology that is distinguishable from magic is insufficiently advanced."

Lackey's corollary is that 'any sufficiently advanced magic is indistinguishable from science'.

 

[Leifmk]

From the point of view of light, light travels infinitely fast.

Technically, light doesn't even have a point of view.

 

[Lexicus]

However we could find ways to go from A to B without having to move through the space between.

Or pinch the space so that it's really small eh?

 

[TheMeInTeam]

I'd like to be proven wrong, but i'm gonna say no to FTL.

I agree with this position.

Even if it is possible through some trick we don't know about yet to get from point A to point B faster than a beam of light traveling in a straight line, it won't be "accelerating to a speed faster than light". It'll be something that hasn't been imagined yet.

But it's hard to envision such a thing while still having a coherent understanding of causality. I've not heard of any "FTL" concepts that a) are physically possible even in principle and b) don't imply the ability to travel to the past and create paradoxes.

Or maybe some answer like "multiple universe theory is right and any universe that creates a time paradox destroys itself" turns out to be the case, but even that would make FTL seem pretty unappealing.

Perhaps the more interesting question is, could we colonize the galaxy traveling much less than the speed of light? There was a paper which suggested that, given the huge amount of planets in the universe, it is very likely that there would have been intelligent life out there. And that, given the age of the universe, this intelligent life would have had more than enough time to colonize the entire galaxy, even if they were traveling only a small fraction of light speed. Yet try as we might, there is no sign of anyone else in this universe.

Yes, and this is more concerning. With machine life or other modifications (allowing for hedge against radiation and enough energy to survive) it should be possible to make multi-decade trips between stars at sub-light speeds. That we see no evidence of this brings up those great filter/fermi paradox problems again.

 

[hobbsyoyo]

That we see no evidence of this brings up those great filter/fermi paradox problems again.

I think it's a mix of four things -
1) Societies tend to destroy themselves before expanding out of their home system.
2) Societies capable of expanding through the galaxy have technologies and means that we are not capable of detecting yet or possibly not even conceive of yet.
3) Societies don't expand out of their home systems by and large and exist in low-impact, low-observability states. If everyone in a society uploaded themselves to the Matrix and it was run on solar power and low-power electronics, you would have a hard time finding that society.
4) Even absent the possibility of 2), we still aren't that good at detecting things even when we're looking for them. We know now there are countless planets (probably the overwhelming majority of stars have multiple planets) but we still can't detect most of them. We also know there are probably more rogue planets (planets without a star) than there are star-bound planets and we can't detect most of these either. It may be the case that any advanced society has tell-tale signatures we should be able to see but just can't because our detection capabilities are so poor, even as we laud our advances on that front.

There is another, less plausible explanation - that we're among the first advanced societies to evolve. It sounds far fetched given how old the universe is but for probably the vast majority of the universe's existence, the conditions for advanced life just weren't met. There were billions of years where the only elements were hydrogen, helium and a bunch of smaller particles. And before that, things were way too hot for anything complex to arise on top of the fact that there was only hydrogen and helium in the universe. Even after more elements began to be manufactured in stars and supernova, it took a long time for those elements to be seeded out in the wider universe in enough concentrations to be notable. Then, even when all of the chemical preconditions are met, it still takes billions more years for complex systems to arise that turn into life which eventually turn into intelligence. And the intelligence isn't necessarily a given, so there are going to be a lot more garden of Eden type worlds than worlds occupied by intelligent beings.


All that said, you are right. A society not much more advanced than ours would have the ability to make generation-ship voyages and seed the stars in just a few thousand years. They should be everywhere but near as we can tell, they aren't. That's quite a conundrum that needs more data to untangle.

 

[Thorgalaeg]

Or pinch the space so that it's really small eh?

Yep. We'll need to find some melange for this guy first:

 

[Hehehe]

I think it's a mix of four things -
1) Societies tend to destroy themselves before expanding out of their home system.
2) Societies capable of expanding through the galaxy have technologies and means that we are not capable of detecting yet or possibly not even conceive of yet.
3) Societies don't expand out of their home systems by and large and exist in low-impact, low-observability states. If everyone in a society uploaded themselves to the Matrix and it was run on solar power and low-power electronics, you would have a hard time finding that society.
4) Even absent the possibility of 2), we still aren't that good at detecting things even when we're looking for them. We know now there are countless planets (probably the overwhelming majority of stars have multiple planets) but we still can't detect most of them. We also know there are probably more rogue planets (planets without a star) than there are star-bound planets and we can't detect most of these either. It may be the case that any advanced society has tell-tale signatures we should be able to see but just can't because our detection capabilities are so poor, even as we laud our advances on that front.

I'm not sure about points 2-4. Even if a civilization were super-advanced, you'd expect them to use technologies such as radio waves for at least some applications (airport radars, low tech communications, etc.) but we're not picking up any. It really does seem like we're alone in the universe.

 

[hobbsyoyo]

I'm not sure about points 2-4. Even if a civilization were super-advanced, you'd expect them to use technologies such as radio waves for at least some applications (airport radars, low tech communications, etc.) but we're not picking up any. It really does seem like we're alone in the universe.

No you shouldn't expect that. Even the Earth is beginning to go radio-dark relative to 50 years ago as tight-beam radios take over from more broad-spectrum (and broadly directional) systems. We are also beginning to deploy fiber and laser networks to replace the old radio links and these won't be detectable at vast distances. Even when we deploy new broadband systems (like cell phone towers), they are much more limited in range than the old TV and radio broadcasts of old and wouldn't necessarily be detected from far away. And to your specific example of air traffic control, even now it's being supplemented (and may one day be replaced entirely) by shorter range transponders, data links and less visible systems like lidar (laser radar).

And all that's happening now with technology we have and understand. Trying to guess what exactly we'd see from more advanced societies and from societies that have a completely different technological framework is a losing game. We think that aliens would think and act like us on some level and that's just a fundamentally flawed assumption in my opinion. For one, just the environment they inhabit will force them down different technological paths. Our atmosphere and our solar radiation force us to use some radio bands and communications links over others, this would not necessarily be true of other species.

Plus, we tend to view our own very recent history as indicative of the way things have to be. When the first alien-hunting radio telescope arrays went up, practically no one considered that advanced societies might not be using the radio frequencies we were looking for in a way we might detect - even as our own technology was moving away from the very things we were looking for. This flawed reasoning has been acknowledged and now scientists are looking for deliberate laser bursts and other potential tell-tale signs of civilization even though there is still an enormous amount of inertia in old-fashioned radio searches.

And in the end, what we are doing ourselves right now is such a vanishingly small snapshot in time. Even if we accepted that all societies will go through a radio-heavy phase (which again, isn't a given), that phase will be exceedingly short if going by our own example. The odds that an advanced society will have gone through it in a window of time where we'd be able to detect it is stupifyingly small - and that's even putting aside the distances involved. If there are other societies on the other side of the galaxy who are broadcasting in a window when we could detect them, we still probably could not based on the distances involved and the amount of stuff between us blocking the signal.

 

[TheMeInTeam]

I'm not sure about points 2-4. Even if a civilization were super-advanced, you'd expect them to use technologies such as radio waves for at least some applications (airport radars, low tech communications, etc.) but we're not picking up any. It really does seem like we're alone in the universe.

We could miss that stuff if it's far away and/or typically a short window in tech development.

I'm not even sure I completely buy #1. Every alien species destroys itself without exception, or some absurdly high %? Even if WE do, it seems to defy probability that every sentient species that develops has traits that lead it to destroy itself. The number of potential areas with sentient aliens in the universe is inconceivably vast. 100% self-kill rate? It might be, but it's hard to envision a mechanism that guarantees that.

None of those explanations are enticing, though maybe #3 is the most of the group. I could at least envision tech advancements becoming increasingly power efficient and then species going into that kind of path, and it would make the window any particular species is observable to us small enough/short range enough that missing them is plausible.

 

[hobbsyoyo]

Yeah I'm not a fan of every society nuking itself to extinction either but it's at least plausible given our own history. I too find #3 to be the most compelling reason though I think we all overestimate our ability to actually spot alien civilizations and underestimate their capacity to do things we can't see by dent of novel technologies we can't anticipate.

I actually think some variation of #3 is the greatest stumbling block to our own colonization of this solar system as I just pointed out in the Mars thread.

 

[El_Machinae]

Robin Hanson talks about 'twenty zeros'.

We look up, and see evidence of 100,000,000,000,000,000,000 stars. We then ask 'why does it seem that none of these stars have produced a galaxy-spanning civilization?'.

Each factor trims away some of the zeros. 2/3 of the stars are so far away that they're in a different epoch. That's a zero. Planets within the life-generating zones only happen in 1 in 100 stars. That's two more zeros. 90% of civilizations burn out their ecology before they can become space-faring, that's another zero. Just like that, I just have to figure out why 10,000,000,000,000,000 stars have failed to produce a galaxy-spanning civilization.

 

[TheMeInTeam]

90% of civilizations burn out their ecology before they can become space-faring, that's another zero.

Where's that coming from?

I don't think we can even assume "habitable zones" as a filter at this point. Uninhabitable for us, but not necessarily other life. Or we're just going assume liquid water is an absolute requirement?

Even if it is, advanced species could easily have found ways to efficiently colonize "uninhabitable" planets to us comfortably.

By yeah, your point still stands. The scales are absolutely incredible even if you make crazy assumptions like that 90%.

 

[hobbsyoyo]

Or we're just going assume liquid water is an absolute requirement?

In short, yes. There may be exotic chemistries that don't require it but really it seems that water is the only really hard requirement we can think of. Water is a universal solvent (really, it's the only such substance we know of) and it facilitates all the other interesting chemistry of life. Everything else seems to be optional near as we can tell. And on those exotic water-less chemistries that may exist - that reinforces the notion that while we may be looking, we don't really know what it is we should be looking for.

Related - if we do find life on Europa or one of the other moons in our own backyard, that alone would radically change the equation in favor of there being lots of civilizations out there. Well, not if we can prove it has a common origin with life on Earth but that's a whole other tangent.

 

[TheMeInTeam]

Related - if we do find life on Europa or one of the other moons in our own backyard, that alone would radically change the equation in favor of there being lots of civilizations out there. Well, not if we can prove it has a common origin with life on Earth but that's a whole other tangent.

It also would raise our expected probability of the filter being in front of us rather than behind . Again, unless it had a common origin with life on Earth. That by itself would have interesting implications.