Anything's possible. I don't know a whole lot about space science, but I think the likelihood would depend on there being planets in the galaxy that formed/cooled/became inhabitable much earlier than our did, giving it's species that much more time to advance. That's probably possible.
I'm going to say I think there is.
There's too many myths that reference people visiting our world, multiple worlds, and similar science fiction concepts.
I suspect the only reason we haven't noticed them by now is they don't use radio signals to communicate.
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Sorry if I'm a bit "rant-y" but this is a subject near to my heart.
It's a hit or miss thing. While there are DEFINITLY other planets, we dont yet have the data to accurately establish how many could develop life. Some scientists (more philosophers considering how much they extrapolate) throw figures around, but they pull most of it out of their a*s, and we DO NOT have any serious data about the composition of other planets, much less the odds that they develop life. (however, within a decade, we WILL have data about other planets atmospheres, possibly from the "gemini planet imager" or "Nfarios", the adaptive optics system for the upcoming thirty meter telescope (TMT))(look those up, they are SUPER cool)
So there are several options:
1) Intergalactic community with prime directive: assuming life tends towards lawful neutral, might exist but seems unlikely. (best for us)
2) Corporative galactic community: a galactic community much like our own. Our planet is simply to uncivilized (and poor in resources) for us to be worth contacting/assimilating so we are left alone (kinda like some islands in the indian ocean). (not so good for us, but I consider fairly likely. However, my sample is biased)
3) Low probability life: life is improbable. The possibility of 2 civilizations of different species existing is so incredibly vast that they will NEVER cross paths.
4) We are alone in the universe: There is nothing but us. (fairly unlikely, but not impossible. Might be impossible to distinguish between 3 & 4)
There may be several specific cases I'm forgetting, but this is from one end of the spectrum to the other.
As for actual evidence of "aliens", I am fairly certain we have no credible evidence. It is simply to easy for a human to become drunk/drugged/confused/disoriented/messed up for me to lend much credence to it. There are so many things that can be confused for weirdness (aurora borealis, spontaneous combustion, bored kids making crop circles, etc.) that the simplest explanation will never be "aliens" to me.
Edit: any mention of "likelihood" in the previous scenarios is PURE CONJECTURE. We only have one "sample" of civilization (our own), and one "sample" of life (the life on this planet) so any statistical analysis on life & alien civilizations will always be conjecture.
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Mathematically, given the number of solar systems out there, and the number of potentially inhabitable planets, and the nature of life itself, which finds ways to thrive in the most inhospitable of places, it seems almost vanishingly remote that our universe isn't loaded with uncountable numbers of inhabited worlds (since we've got 200 million stars in the Milky Way, any one of which could have one to three planets in the 'Goldilocks zone,'), and there are estimated to be one hundred billion *galaxies* in the observable universe, some much bigger than our own...).
On the other hand, we've *almost* got 3D printing down, and we've *almost* got clone-generated meat (although it apparently tastes blah), and with the tiniest exertion of political will on our part (yeah, that last part is sheer science fiction...), we'd eliminate most resource shortage issues and be able to synthesize everything anyone would ever need from the comfort of their own homes.
Any alien race capable of getting out of their own solar system would have already beaten this, as well, and therefore have no *material* reason to ever get off their couch. If they want to learn about our culture (such as it is), they can just turn on the radio-telescope and listen to all the crap we are broadcasting into the ether, which, looking at the stuff in my Hulu queue, could serve as the only explanation we'd ever need as to why no advanced species has ever contacted us... :)
Next week on, As the Brain Turns;
Ghosts! Restless spirits of the dead, or grainy images of far-future archaeologists using remote chroniton projection scanning technology to study what, to them, is ancient history?
I like the majority theory that many authors have put forth, tongue in cheek as it were. Humans are intentionally isolated from the galactic community. As a whole, humanity is most easily compared to by galactic races as a multi-celled, sentient megavirus, only capable of infecting and destroying everything they touch. Kind of like the CDC, humans are allowed to fester on one planet as a petri dish for innoculation, should the galaxy need it.
(since we've got 200 million stars in the Milky Way, any one of which could have one to three planets in the 'Goldilocks zone,')
Eh, I don't know if I would use that as a standard. Currently, there are precisely zero known life-supporting Goldilocks planets. Plus, some gas giants radiate enough heat and light to act as stars, so we could find a lot of habitable life on moons.
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I like the majority theory that many authors have put forth, tongue in cheek as it were. Humans are intentionally isolated from the galactic community. As a whole, humanity is most easily compared to by galactic races as a multi-celled, sentient megavirus, only capable of infecting and destroying everything they touch. Kind of like the CDC, humans are allowed to fester on one planet as a petri dish for innoculation, should the galaxy need it.
See, I find this an excellent example of human presumption. We can never consider ourselves "just average" or somewhere near that. We can never help but feel we should either be "the best" or "the worst" (that type of attitude is also seen a lot in american media, from heroic (USA save the world) to post-apocalyptic (USA destroy the world)). It's like the "human bias" in fantasy/scifi, even when it doesnt particularly make sense humans always got to be dominant (pathfinder is the only system I know where this makes sense since they are the only race that can be good at everything). However, I dont even know if we will ever be able to seriously compare 2 sentient forms of life though (who knows how aliens would think).
As for the numbers arguments... yes, there are billions of billions of potential planets. A fraction of those could support life. Another fraction does support life, etc... However, we don't know what the fraction is, and speculating on it is fruitless without more data (which we could be working on getting). I'm trying to do my share (currently doing an engineering masters working on improving telescope technology) and I wish there where more people putting their effort as well rather than speculating.
Then again, this isnt exactly very lengthy speculation, so I wouldn't say it's time wasted as long as it gets some folks thinking seriously about space exploration.
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Alright guys let me sum this up for you
It is known that there are an infinite number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the Universe can be said to be zero. From this it follows that the population of the whole Universe is also zero, and that any people you may meet from time to time are merely the products of a deranged imagination.
Therefore not only is there no galactic community, there isn't even an Earth community
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Alright guys let me sum this up for you
It is known that there are an infinite number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the Universe can be said to be zero. From this it follows that the population of the whole Universe is also zero, and that any people you may meet from time to time are merely the products of a deranged imagination.Therefore not only is there no galactic community, there isn't even an Earth community
Yes, exactly.
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Even if we aren't alone, you can't go faster than the speed of light, so we won't be crossing paths anytime soon.
I'd like to think there are others out there, but we probably won't ever know for sure. I'm kind of surprised nobody's mentioned the Drake equation yet.
I think I kinda implied it (when I was talking about stuff that is more philosophical than scientific), but it should have been mentionned. It's an interesting thought experiment, but it's one that's JUST vague enough that you cant really say it's invalid, but not precise enough to provide any insight.
The numbers are especially frustrating to me. 100% estimate that a planet that can develop life will develop life? And intelligent life at that? It gives me a headache just thinking about the problems with those numbers.
The only parameters we might have an estimate for soon are f_p (% of stars having planets, which might approach 100%) and n_e (number of planets in a habitable zone) (whithin the next couple of decades, enough exoplanets should be found that we might be able to evaluate that). R_* might be determined, but it's hard to get a good sample size. The other parameters are whatever you want, we wont have a reliable estimate until the equation becomes largely irrelevant (since we will have had to encounter other space civs).
Another issue is time. There could have been a intergalactic civilization that existed a million years ago but we'll never know it (unless we find its ruins). Or one may exist a million years from now which makes it irrelevant as far as we're concerned. Or everyone could be in the same development stage we're in now and are just now barely getting off their own planet.
The speed of light limit is the biggest hinderence to a galactic community. If Einstein was right then regardless of how many planets with life there are, it would take incredibly an long-lived species or extremely patient one (sending missions lasting hundreds of generations) for there to be any real physical contact between societies. And even then, each planet would still be effectively isolated with maybe the odd "ambassador" who survived the mulit-generational trip to visit.
As much as it may not be very romantic, the universe wasn't made for us. And its vastness is a rather cruel joke to those of us who fantasize about something grander. (And I consider myself one of those.)
Greg
I think life is probably at least somewhat common. I also think that there are probably at least a few other sapient species out there.
But I am not convinced that interstellar travel is that feasible, so no, I don't think there really is much of an interstellar community out there
I will note that traveling faster than the speed of light is actually possible under general relativity.
It's not just a straight curve upward; the graph is actually a bell graph. You don't see the other side of the slope because, most of the time, they don't display it out of feeling there's no point; just because traveling faster than the speed of light does not require infinite energy does not mean that they consider it practical to model. In fact, when traveling faster than the speed of light, it is actually theoretically possible for you to be travelling fast enough to have a negative mass.
This is just one of several quirks in general relativity and one of multiple areas where it produces weird or nonsensical results.
I don't think the speed of light would be much of a hindrance at all; I kinda suspect that the universe is a lot more complicated than we think it is. The biggest hindrance? Even within our galaxy, space is mostly empty. Finding each other would be pure luck.
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One interesting possibility out there is that the universe (as it is) is a simulation. Several indicators (apparent speed limit, apparent minimum observable size, others that I dont quite remember) suggest we might be in a simulation. So maybe all we need to do is find the "bugs" in the simulation that allow us to travel.
It's nonsensical speculation, and impossible to demonstrate, but it's a funny idea nonetheless.
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I will note that traveling faster than the speed of light is actually possible under general relativity.
I only took general and special relativity in undergrad, but my understanding is that the speed of light is a barrier. One cannot cross from sub-light to supra-light speeds. In fact, IIRC the rise of mass as one accelerates to c has been shown in particle accelerators. (Mass goes as 1/ sqrt (1-v^2/c^2)). You may not have infinite mass while going faster than c but you will get there trying to accelerate from less than c.
So unless you start out at supra-light speeds, you are stuck at sub-light speeds.
Greg
Yeah, GregH, you're right, MagusJanus is way off. There's no bell graph to acceleration up to/and over the speed of light. It's in the math, there's 1 divided by X, where X is the square root of 1 - (v^2/c^2), where v is the velocity of the mass (a proton or a spaceship) and c is the speed of light. So if v == c, then you have X being square root of (1 - 1), or square root of 0, which is 0. 1 divided by 0 is...not applicable. As v approaches c, the mass approaches infinity and an infinite mass would, well, take up everything and be everywhere at once. And you can't magically jump some mass from a v < c to a v > c, the acceleration requires a unbroken increase in velocity.
The math does support faster than light travel that moves backwards in time however. But it's an asymptotic break in the graph between forward time and backward time at the velocity of c. Tachyons are hypothetical particles (meaning have not been experimentally discovered) that move faster than light and backwards in time. Getting a real mass particle on the other side of the asymptotic barrier...well, Nobel prize for you if you figure it out experimentally.
But a real mass particle, under relativity, is prohibited from FTL or even travel at the speed of light by the rules of relativity.
And as far as I know, there's no negative mass particles. There's zero mass particles (photons and gluons) and then everything else has mass.
Huh.
If you guys will excuse me, I have a science teacher to call up and tell them how badly they failed me.
Hopefully if there is they won't blow up our planet to four lane a space highway.
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Huh.
If you guys will excuse me, I have a science teacher to call up and tell them how badly they failed me.
Well, GregH stated he "took general and special relativity in undergrad" and I have a double degree in History and Physics, with a focus on astronomy for the Physics and worked for several years on a helping create cosmology undergrad science course led by head of the physics department.
But as a trained scientist, I'm willing to accept that anything I wrote (or write in the future) was/is wrong and/or inaccurate if evidence is presented. And will readily admit that not a day went by during that work that the two PhD's didn't expound upon some aspect that I was getting wrong.
But I have 95% confidence in what I wrote about what happens to an object with mass as it approaches the speed of light, the asymptotic barrier that's inherent in the equations, and so on.
It's why us finding a planet with a technologically advanced life would be so extremely frustrating. The nearest star is just over 4 light years away, so a conversation with them would go; Earth "Hello?" 8 years later: Alpha Centauri (AC) "Yeah?", us "Hi." 8 years later: AC "Uh, hi?", us "A/S/L?" 8 years later, AC "creep much?" There ends a 24 year long conversation.
And even if we were able to travel at 100 times the speed of our fasted current travel speeds (which would be 0.0134 times c, 1.34% of the speed of light), it would take us about 300 years to physically get there (and another 300 years to get back). And that's the closest star to us (other than the Sun) at just over 4 light years away...in a galaxy that's, for the disk, ~1000 light years thick and about 110,000 light years in diameter. Even if we could push our speed to half the speed of light then we're talking 2 years to AC and 2 years back but it would still take 500 years to get from the top to the bottom of the Milky Way and over 50,000 years to get from one side to the other. If a ship left Earth at half the speed of light when we were making cave paintings in Lascaux France, the ship today would only be 36% across the width of the Milky Way.
So we're left hoping for warping spacetime/creating stable wormholes to travel through. But the materials needed to make those...we haven't discovered and the energy needed to power something like that...through the roof. Most likely. We may discover something that makes it a reality but it's very improbable.
But for a campaign...throw in some juicy technobable like "fluctuating tachyon fields" and let ships fly at warp speed or corporations develop wormhole portals.
Reality should never stand in the way of a good campaign.
I wasn't being sarcastic in my previous post; I meant that quite literally.
I have no reason to disbelieve any of you; I was simply wrong in what I knew.
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No worries, MagusJanus. Text always carries the concern that tone will be misinterpreted and I admit on first reading of your post it came across as negative but after I was a few sentences in on writing my response I realized I had no justification for that interpretation. So I apologize if the start of my response post felt defensive/attacking, was just meant as a clarification of where I'm coming from.
But I realized I made a mistake. At half the speed of light, travel to AC would take 8 years there and 8 years back, not 2 and 2. And it would take 2000 to get from top to bottom of our galaxy and ~200,000 years to get across it. Not what I listed, I was dividing by 2 when I should have been multiplying (making the mistake of "half" the speed of light and then halving the numbers instead of doubling them, le ug).
I tend to be perfectly fallible.
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Stephen Hawking has put it quite nicely, if not very hopefully. An encounter between us and some starfaring race would involve us meeting up with beings much more technologically advanced than us. The result could easily be rather like Europeans encountering American Indians or other less advanced native peoples. The results were almost universally bad for the less advanced peoples, up to and including genocide.
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"There are two possibilities. Either we are alone in the universe or we are not. Each is equally terrifying." Arthur C. Clarke.
I don't know shiznit about physics and what not, but I do read science fiction novels occasionally, and, this week, I've been reading about the utods, with whom I'd love to be in a galactic community.
I remember watching a science show on this subject, wish I had a better memory and could remember the full details. Im sure they said that since the speed at which you travel effects the passage of time; while it may take (8?) years to get to Alpha Centauri as far as the people of earth are concerned, the people on the ship would measure the time in months...
So star travel could be possible with only one generation of humans... at less for the ones on the ship.
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I remember watching a science show on this subject, wish I had a better memory and could remember the full details. Im sure they said that since the speed at which you travel effects the passage of time; while it may take (8?) years to get to Alpha Centauri as far as the people of earth are concerned, the people on the ship would measure the time in months...
So star travel could be possible with only one generation of humans... at less for the ones on the ship.
Absolutely. Time dilates as you approach the speed of light. But even then stars are very far apart. But even more than that, you need the political will on Earth (or whatever home planet) to fund a project that no one supporting it will ever see the results of. That would be an impossible sell in any country here now, and unless we become far more "enlightened" as a species I don't think it ever will. (And I'm not holding my breath on that one.)
Greg
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It may be possible to star travel but not go faster than light. Two methods
1 slowship. Construct a flying ark, so to speak. Crew of tens of thousands, complete industrial plant. The vessel travels at about 0.5C. The craft stays in contact with earth, albeit with a fair amount of lag. Send multiple vessels. These would be fully a functional community.
2 albucurrie derive (probably mis spelling that). Warp space to provide fast travel. Ship never actually reaches lightspeed but warping of space gives that effect. Has problems like a masive discharge of radiation on arrival, but that may be amiliated. (For example don't arrive directly in target system, but outside and let the inverse square law be your friend. Then do ordinary travel in system.)
To say it can't be done lacks...ambition.
Space warping FTL presents problems with causality. It is actually time travel, even when it seems like it's just going faster.
Thus, rather unlikely.
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1 slowship.
No one disagrees that this is possible. But as a means of developing a "galactic community" it's basically a no-go.
2 albucurrie derive (probably mis spelling that). Warp space to provide fast travel. Ship never actually reaches lightspeed but warping of space gives that effect. Has problems like a masive discharge of radiation on arrival, but that may be amiliated. (For example don't arrive directly in target system, but outside and let the inverse square law be your friend. Then do ordinary travel in system.).
Also the negative energy requirement is a bit of a hurdle. If (and that's a big "if") White's experiments support his warp drive hypothesis then we'll talk. Until then it's just another idea...
To say it can't be done lacks...ambition
One person's "lack of ambition" is another person's "living with the laws of physics".
Greg
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Well, they managed to accelerate a laser.If (and that's a big "if") White's experiments support his warp drive hypothesis then we'll talk. Until then it's just another idea...
Who are "they" and what does "accelerate a laser" mean?
Lasers collimate light into a focused beam. The "stuff" coming out of a laser is light, photons, which moves at c. There's no way to accelerate, increase the velocity, of light. "Adding" more energy to light just increases its wave frequency/lowers its wavelength. A gamma ray is the same as visible light or a radio wave, just with a lot more energy...but they're all still moving at the same velocity; c.
Otherwise, lasers are used to accelerate (mass) particles, such as electrons for use in particle accelerators, medical equipment, and (it is hoped) for sustainable fusion.
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Well, they managed to accelerate a laser.If (and that's a big "if") White's experiments support his warp drive hypothesis then we'll talk. Until then it's just another idea...
Who are "they" and what does "accelerate a laser" mean?
Lasers collimate light into a focused beam. The "stuff" coming out of a laser is light, photons, which moves at c. There's no way to accelerate, increase the velocity, of light. "Adding" more energy to light just increases its wave frequency/lowers its wavelength. A gamma ray is the same as visible light or a radio wave, just with a lot more energy...but they're all still moving at the same velocity; c.
Otherwise, lasers are used to accelerate (mass) particles, such as electrons for use in particle accelerators, medical equipment, and (it is hoped) for sustainable fusion.
Eh, there might be a few things that need to be qualified there; colimating a beam of light has no effects on the photons themselves. When it is said that there is "more energy", it needs to be specifided that we add more energy to the photon (either through nonlinear effects or just a different medium to produce the light in the first place). We need to be very careful about differentiating the photon's energy (joules, generally very low quantity per photon), the power in the beam (Joules/second), and the energy in the beam (power integrated over time). It's important to distinguish these elements because a lot of folks (me included, until I got the courses) dont properly understand the quantification of light.
However, there is no way to go faster than c, the speed of light in the void (as far as we know) (this is true for everything from radio waves to gamma radiation, which are all photons, with different wavelengths). It is possible to go faster than light IN SPECIFIC MEDIUMS because the speed of light in something that isnt the void is c/n, the index of refraction. Electron going faster than c/n can be observed in certain nuclear reactors, and this gives off a blue light called "cherenkov radiation".
Another long-winded post, largely because I did a lot of work with lasers in my undergrad. Fun stuff.
Interestingly enough, you can also use lasers to cool things to near 0 Kelvin temperatures, but I'll admit I'm unfamiliar with the techniques.
From what I understand, warping space does not have time dilation, as the vessel never actually goes faster than the speed of light. I don't understand the maths (hulks head hurts) but I am told it is possible.
As for a slowship galactic community, well it is possible for a quantum singularity communicator, which has been shown to be ftl (actually thats not what really happens but it is the effect.) After all we have community, and most of it is text based.
If life extension tech comes through, then a local civilization is possible. After all empires existed in the 19th century with travel times of a year or more. If people can live, well indefinitely in one form or another, then ten or twenty years travel is not an issue. Remember, communication should be fairly constant, especially if the quantum singularity communicator is available.
Hey its all speculative, but it may work.
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As for a slowship galactic community, well it is possible for a quantum singularity communicator, which has been shown to be ftl (actually thats not what really happens but it is the effect.) After all we have community, and most of it is text based.
No, that is functionally impossible (as far as we know, though it could change one day). I've done my quantum mechanics, and talked with a lot of professors, and it is fundamentally impossible to transmit information faster than the speed of light in the void. I'm going to ask for a reference, because as far as I understand that's star trek stuff and isnt possible in the real world. Certain cases that give the impression of "instant, ftl transmission" like quantum entanglement only give that appearence under certain very specific interpretations of what happens.
Interpretation (and semantics) can give some weird ideas to the layman; for example, shrodingers cat. The thought experiment was originally created as an example of how ABSURD the "copenhagen" interpretation of quantum mechanics was, and quite a lot of physicists disagree with it.
And I hate these arguments & weirdnesses, especially when they get out to the public, because it gives a very false impression of what science can do. Journalists really dont help, since except for specialised science journalists, most dont have the training to evaluate the quality of the information.
NERDS!
:)
Wish I knew enough about physics to contribute, but reading this is fascinating.
Actually I prefer geek. Williamoak, I would be interested in that reference, but nothing I have read has said its impossible. Maybe hard, and expensive and unlikely, but not impossible.
Whats needed I feel is somengenius to make it happen.
BTW by saying that I'm not denigrating the abilities and contributions any in the field, many of whom are certifiable geniuses as far as I am concerned, but I am talking about the person who makes the paradigm shifting discovery .
Or it might not happen. Still it's something interesting.
Actually I prefer geek. Williamoak, I would be interested in that reference, but nothing I have read has said its impossible.
What one needs, and what science can only really provide, is what's possible, not what's impossible. Even with the speed of light, the math doesn't say "you can't travel faster than the speed of light" it really says "as you approach the speed of light, mass goes to infinity". From that we can infer that "you can't travel faster than the speed of light" because we know that F=ma (force equals mass times acceleration) and if the mass goes to infinity, then the force must also go to infinity for any acceleration greater than zero. Since applying a force requires energy, then an infinite force requires infinite energy. We know there is a finite amount of energy in the universe, so we can't accelerate an object from below light speed up to c.
So, with regards to ftl communication, one must assume it is not possible until someone shows that it is possible. (One can never prove a negative, but the absence of any proof that it is possible can be very convincing...)
Greg
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The main problem I am seeing with this discussion of FTL is that the whole issue of problems with the light speed barrier assume there's only one set of laws of physics That assumption is what fuels the hunt for Unified Field Theory.
Problem: There's absolutely no evidence that the universe operates under a single set of physics, and plenty of things are are problematic in both relativity and in quantum mechanics. And several items where the explanations they have to use grow increasingly complex as time goes by just to keep the items within the purview of physics as we know it.
I won't get into my long bit about how much science actually relies upon assumptions, but that essential core assumption about how the universe works is potentially problematic, especially given the number of times they've repeatedly been shown the universe doesn't actually work the way we thought it did.
So, what if science is wrong? What if relativity and quantum mechanics are operating under different sets of physics entirely? And what if gravity is operating under a third, one we don't know much about yet? What if there's more? What if Unified Field Theory is just science tilting at windmills and the majority of the universe as we see it exists in the cracks where these different fields of physics interact?
Scary thought, isn't it?
But in that scenario, FTL travel would be potentially possible, using one of the sets of physics outside of the ones we're currently aware of. Of course, we still wouldn't be likely to see any other races traveling at FTL speeds or visiting us; the galaxy is a big place, after all, and they might not know our planet even exists.
No worries, MagusJanus. Text always carries the concern that tone will be misinterpreted and I admit on first reading of your post it came across as negative but after I was a few sentences in on writing my response I realized I had no justification for that interpretation. So I apologize if the start of my response post felt defensive/attacking, was just meant as a clarification of where I'm coming from.
But I realized I made a mistake. At half the speed of light, travel to AC would take 8 years there and 8 years back, not 2 and 2. And it would take 2000 to get from top to bottom of our galaxy and ~200,000 years to get across it. Not what I listed, I was dividing by 2 when I should have been multiplying (making the mistake of "half" the speed of light and then halving the numbers instead of doubling them, le ug).
I tend to be perfectly fallible.
When you posted, I realized that my comment came across as being sarcastic from your post. Nothing in it came across as defensive or attacking, but more as someone responding to sarcasm ^^
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The main problem I am seeing with this discussion of FTL is that the whole issue of problems with the light speed barrier assume there's only one set of laws of physics That assumption is what fuels the hunt for Unified Field Theory.
Problem: There's absolutely no evidence that the universe operates under a single set of physics, and plenty of things are are problematic in both relativity and in quantum mechanics. And several items where the explanations they have to use grow increasingly complex as time goes by just to keep the items within the purview of physics as we know it.
I won't get into my long bit about how much science actually relies upon assumptions, but that essential core assumption about how the universe works is potentially problematic, especially given the number of times they've repeatedly been shown the universe doesn't actually work the way we thought it did.
So, what if science is wrong? What if relativity and quantum mechanics are operating under different sets of physics entirely? And what if gravity is operating under a third, one we don't know much about yet? What if there's more? What if Unified Field Theory is just science tilting at windmills and the majority of the universe as we see it exists in the cracks where these different fields of physics interact?
Scary thought, isn't it?
But in that scenario, FTL travel would be potentially possible, using one of the sets of physics outside of the ones we're currently aware of. Of course, we still wouldn't be likely to see any other races traveling at FTL speeds or visiting us; the galaxy is a big place, after all, and they might not know our planet even exists.
What if magic is real? :O
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So, what if science is wrong? What if relativity and quantum mechanics are operating under different sets of physics entirely? And what if gravity is operating under a third, one we don't know much about yet? What if there's more? What if Unified Field Theory is just science tilting at windmills and the majority of the universe as we see it exists in the cracks where these different fields of physics interact?
Scary thought, isn't it?
First off, science isn't a "thing" it's a process. More accurately it's the scientific method. "Science" as you define it, is everything we have ever learned using that process.
Now yes, it is true that current scientific study is based on the assumption that the laws of physics, as we understand them, apply to all of the observable universe. But two things: 1) we've seen nothing so far to counter that and 2) you gotta start somewhere.
If someone actually provides evidence (not just conjecture) that the laws of physics are not universal but rather location-specific, I'm sure most scientists will not find it scary at all, but rather a challenge. A rather daunting one, but a challenge nonetheless.
Greg
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Adding to what GregH said;
The phrase "sets of physics" doesn't mean anything. Physics is energy and matter and how they exists in nature and/or the study of energy and matter in nature (nature meaning, for us today, the whole of the cosmos).
There are no "sets" of physics. There's subsets, to be sure...energy or matter, but no sets.
If feels like, though I could be wrong, you are using "sets of physics" to mean Scientific Theories, as in General Relativity or Quantum Field Theory, MagusJanus. And that, therefore, GR or QFT may be wrong.
"Wrong" is, pardon the wording, well, to say "wrong" is wrong. Science is concerned with accuracy and precision not wrong or right. Ang because GR and QTF have been experimentally verified for well over 50 years (in the modern era, no less) they are not one day going to suddenly be found to be invalidated.
As a great and wonderful example. About 400 years ago Newton described how gravity worked. Newtonian gravity. And his scientific theory on gravity works. Still does. It is accurate and precise when you apply it to people or planets. But very soon after the introduction of Newtonian gravity, along with the discovery of the finite speed of light, people began to ask what happens to objects with mass far beyond anything humanity has encountered...Newtonian gravity doesn't work; it becomes wildly inaccurate and imprecise. But that doesn't mean that it doesn't accurately describe gravitational effects for things like people and planets.
Then in steps Einstein about a 100 years ago with relativity and his scientific theory accurately describes gravity for people, planets, and infinitely dense black holes. Relativity is more accurate than Newtonian and Relativity didn't show Newtonian as "wrong."
So today we have Relativity which is amazingly accurate in describing gravity on one hand and QTF for describing and predicting all other forces we know about. And because of the nature of the knowledge that we've gain from QTF (partical accelerator experiences for example) we have an exceptionally high degree of certainty that there are no other forces at work in the universe...or at least if there are they will be so small as to in no way be able to interact with normal human senses or the physical world we're used to.
Now make a venn diagram of QTF and Relativity and where they overlap is where the current issue is. QTF says the "fabric" of spacetime is lumpy, bubbly, and constantly influx with paired particles popping into existence and then annihilating themselves mere moments later. But Relativity says the fabric has to be smooth. Essentially Relativity is experiencing what Newtonian gravity experienced but at the opposite end of the scale. Newtonian broke down at the extremely large/massive and Relativity does at the small scale...if QTF is right (and the Fermi Space Telescope was actually able to test this bumpy "quantum foam" idea and it was able to push the "size" of the foam into a smaller corner because it didn't find it at the scale it was able to look). But it could be QTF's issue and that spacetime is smooth and QTF will have to be modified or subsumed into a different scientific theory...but if it does that doesn't mean your computer is going to stop working because all of a sudden QTF is wrong...you'll still be able to use QTF from now until a million years and more to make computers or smash particles together regardless of what a Unified theory says or does.
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So do we know what dark matter is now?
I think AAS (American Astronomical Society) is still meeting this week, so something may come out there, but it's still unknown...other than it has mass and doesn't interact with light. Dark matter, and then dark energy, are two of the big fun unknown of astronomy. WIMPs and MACHOs were the two big candidates for dark matter, but at least one of those went to the unlikely bin a few years ago (forget which one, but I think it was WIMPs as the big candidate was the neutrino but after they determined neutrino's change flavor in their travel from Sun to Earth it made the number of known neutrinos to be far less that what would be needed for them to account for dark matter...I think that's how that went down, but I could very off on that).