Game starting at 1979...

[TrashMan]

Who says aliens want to conquer us? From what I have heard, the general consensus is that they simply want to probe our butts.

If FTL travel is ever harnessed by Earth, then I believe butt probing would of a higher priority than invasion.

We must prepare for the ineviatable scientific expedition.

[Sinfullyvannila]

It cannot be possibly realistic, that's the point! Humanity has no chance of survival in that scenario. If the game is realistic the game canot exist. Just roll with the game. No XCOM game is ever realistic.

Games don't need realism to be fun. And a lot of games (including this one) are not possible if you ground yourself in realism too much.

You know their goal isn't to invade in either X-Com or XCOM right? They are trying to infiltrate through terror. In the first one they don't have FTL, in the second one it seems they do. But they aren't trying to invade in either. But in any case, the technology that they use to wage war on us is not too far ahead of our own, otherwise, we wouldn't be able to comprehend and reverse engineer it so easily. The reason for this is since necessity is the mother of invention, and there is very little reason to continue to develop that specific technology any further. Have you read much hard sci-fi? People don't wage war with necessarily "high-technology" weapons, not because they can't but because it's just not very effective. I've read books where capital ship-to-ship combat is waged with SAND, and ones where they use ICE for armor, because those are actually very cost effective weapons. I don't know about Xenonauts though, it appears that it is their intent to invade.

So in these games, they aren't using their technology to the full, because it goes against their goals to wipe out humanity, so in the X-Com games, it's actually pretty realistic to thwart the alien's plans.

[panzereich]

Ok. I admit I was being pretty far fetched with the whole anal probe thing, I guess I watch way too much Southpark.

The real reason for the invasion is that America's radio waves reached their planet, they got a whiff of matchbox 20 and had to put a stop to it.

[tiger12348]

And you're missing the point.

Any new theory or formula MUST explain all the experimentaly proven results of former theories.

We know some of the basic laws of the universe. They are immutable. Laws like Thermodynamics. Conservation of energy, etc..

No alien technology can break those laws.

First of all, I am not here to introduce a new theory that breaks Thermodynamics. Laws of the universe are excellent modules that accurately describe everything we observe without exceptions... SO FAR. Once an exception is found (not saying it ever will be), that's all it takes to break a theory, what would the physicists do? Ignore it? No... here is what science comes into play, a new module must be found, it could be a daunting task and until that all we can say about thermodynamics is it is our current best module that explains what is going on. Essentially, this process is what makes science so exciting.

As soon as we see a FTL civilization, they have already broken the universal speed law, or more likely found a way around it. This shows their mastery over the fabric of space-time, and if they are hostile, we don't stand a slight chance.

I'm a religious person yet you won't see me worshping an alien with a plasma rifle.

And 3D holograms? Whom do you think they would fool?

A hologram won't fool any scientist on the planet. A holographic representation cannot be the same as the real thing because they are fundamentaly different in it's properties.

A hologram won't fool any scientist on the planet, yes. However the point is 3D hologram is an over kill for people who want to believe there is god and after life, which is the majority, turning them against the minority with alien weaponry will force an unconditional surrender.

An alien would have to do something FAR more impressive than that.

Like come back from the dead.

And what if they can do some miracle healing:) will that do?

Edited October 23, 2012 by tiger12348

[tiger12348]

The hoi polloi might.

Will the Pharaoh?

He kinda likes his position and lifestyle, you know.

Note that, the Pharaoh enjoys his power and lifestyle only because the hoi polloi believes he is someone special that deserves the position.

[HWP]

Note that, the Pharaoh enjoys his power and lifestyle only because the hoi polloi believes he is someone special that deserves the position.

Mostly it's because he holds the power, godlike status is not a source of that power, it's a perk. Also because he'll kick the ass of anybody who says otherwise.

A hologram won't fool any scientist on the planet, yes. However the point is 3D hologram is an over kill for people who want to believe there is god and after life, which is the majority

You included? No offense, but why do you then see everyone else as so stupid.

As soon as we see a FTL civilization, they have already broken the universal speed law, or more likely found a way around it. This shows their mastery over the fabric of space-time, and if they are hostile, we don't stand a slight chance.

We have broken the speed of sound, making us masters over the atmosphere; so why do we still rely on dubious weather forecasts rather than make our own weather?

And I once again have to repeat that effectively faster-than-light travel is already well possible, provided an energy source. It's not even hard. You keep accelerating and it doesn't suddenly stop or slow down, you start approaching your target at 350,000 km/s, 500,000 km/s, 1 billion m/s. The general populace doesn't seem to understand even special relativity and imagines the speed of light like a highway speed limit. Which it's not, it's not even the sound barrier, that at least produces a shockwave.

As for need for "true quasi-FTL" - even the phrase sounds silly, that's because every FTL travel method will be subject to debate as to whether it is indeed FTL or not. There's no "you have FTL", "you don't have FTL", it's not a switch, it's all on a continuum in between.

Not that it matters. You need "true FTL" if you want to live on Aldebaran, at 9am commute to work to Betelgeuse and hang out at a bar on Canopus on caturday night, like in a trashy 25-cent drive-in space opera. For purposes that are not so naively anthropomorphic as to try and make suburban life "In Space!" you don't, and what fits in with General Relativity is sufficient.

[tiger12348]

You included? No offense, but why do you then see everyone else as so stupid.

It really has nothing to do with intelligence, believing in something without anything going for it whatsoever, takes faith.

We have broken the speed of sound, making us masters over the atmosphere; so why do we still rely on dubious weather forecasts rather than make our own weather?

And I once again have to repeat that effectively faster-than-light travel is already well possible, provided an energy source. It's not even hard. You keep accelerating and it doesn't suddenly stop or slow down, you start approaching your target at 350,000 km/s, 500,000 km/s, 1 billion m/s. The general populace doesn't seem to understand even special relativity and imagines the speed of light like a highway speed limit. Which it's not, it's not even the sound barrier, that at least produces a shockwave.

Masters of atmosphere does not grant you the ability to control weather, simply because the position and distance of the sun from the earth along with the gravitational effect of the moon is what makes us rely on weather forecast.

Unfortunately, energy source is really the problem, remember we still rely on fossil fuels. As you accelerate towards the speed of light, the amount of energy required approaches infinity regardless of the rest mass of the object... infinity as we know, causes problems in the physical world.

[HWP]

It really has nothing to do with intelligence, believing in something without anything going for it whatsoever, takes faith.

Yes. And does the fact that billions of people fail to believe in evolution, despite overwhelming evidence for it, tell us something else?

Masters of atmosphere does not grant you the ability to control weather, simply because the position and distance of the sun from the earth along with the gravitational effect of the moon is what makes us rely on weather forecast.

How strange. Mastery of a slave does grand you the ability to control what he does. Perhaps, then, we might not be so much masters of the atmosphere as merely kids who have figured out how to ride a surf wave?

As you accelerate towards the speed of light, the amount of energy required approaches infinity regardless of the rest mass of the object... infinity as we know, causes problems in the physical world.

You should have read my post more thoroughly. It doesn't work like that, you misunderstand relativity. Like I said, you can reach the speed of light, cross it, go to twice that, to 10c and further. To clarify further, you will not notice any change in acceleration along the way. No asymptote, no approaching infinity.

If you apply a force of 95 meganewtons to a 10,000 metric ton craft, it will keep producing an acceleration of 9.5g, or 10c/year, and if you're headed towards a star 500 light-years away, you will get there right on time, in 10 years. All happening exactly how Newtonian physics predict it.

There is only one small caveat, but I'll let you redeem yourself by figuring out what it is. But I'm not being ironic in calling it small, it really is pretty minor, for purposes we have in mind here.

[tiger12348]

Mostly it's because he holds the power, godlike status is not a source of that power, it's a perk. Also because he'll kick the ass of anybody who says otherwise.

Pharaoh are ordinary people if we put them in a modern society where the majority believes in democracy, their power back then ultimately come from the the hoi polloi.

Yes. And does the fact that billions of people fail to believe in evolution, despite overwhelming evidence for it, tell us something else?

I can assure you that if even the slightest evidence supports religious belief, it would not go unnoticed, and yes a fully interactive 3D hologram is going to be a overkill because of the desperation.

You should have read my post more thoroughly. It doesn't work like that, you misunderstand relativity. Like I said, you can reach the speed of light, cross it, go to twice that, to 10c and further. To clarify further, you will not notice any change in acceleration along the way. No asymptote, no approaching infinity.

If you apply a force of 95 meganewtons to a 10,000 metric ton craft, it will keep producing an acceleration of 9.5g, or 10c/year, and if you're headed towards a star 500 light-years away, you will get there right on time, in 10 years. All happening exactly how Newtonian physics predict it.

There is only one small caveat, but I'll let you redeem yourself by figuring out what it is. But I'm not being ironic in calling it small, it really is pretty minor, for purposes we have in mind here.

Relativity tells us that for an stationary observer out side your craft, the mass of the craft increases as it approach the speed of light, F=ma => a=F/m, thus acceleration appears to be decreasing.

For you on your craft, you won't notice increase in mass, and as you approach the speed of light, time slows down on your clock, thus you will be approaching c forever.

For both observers, the speed of the craft approaches c but never get there, since science is based on observation and velocity is defined by v=at.

And more importantly, a CONSTANT force is required for your craft to keep producing an acceleration, which leads us to infinite energy again, we can't just make this assumption.

Edited October 23, 2012 by tiger12348

[HWP]

Ok. I admit I was being pretty far fetched with the whole anal probe thing

Now, that's just really dirty. Don't do it man, at least don't push these things too far.

[HWP]

Relativity tells us that for an stationary observer out side your craft, the mass of the craft increases as it approach the speed of light, F=ma => a=F/m, thus acceleration appears to be decreasing.

Correct.

For you on your craft, you won't notice increase in mass, and as you approach the speed of light, time slows down on your clock, thus you will be approaching c forever.

Not correct. Neither increase in mass nor any slowing down of your clock happen for you. Your time flows as normal, and your speed, calculated as v=dx/dt, where x is your distance from the starting point, measured at the beginning of your journey, will seamlessly reach c, exceed c, and keep growing.

This is not an illusion or failure to notice things. It's as true for you as what the outside observer experiences is true for him. So if dx/dt>c doesn't count as faster than light travel, what does?

For both observers, the speed of the craft approaches c but never get there, since science is based on observation and velocity is defined by v=at.

The last equation keeps true. And a=F/m where F is thrust. So v=t*F/m. As t grows and a remains constant, what happens to v?

Remember, there is no absolute velocity. No stationary observer - no stationary object at all - only a pair of objects can be stationary relative to one another. You are never actually approaching the speed of light, it's more like objects approaching it relative to you. Think of it this way: you are always in Newtonian space, it only gradually turns Einsteinian for long distances.

Of course, distance itself is relative as well. It's very hard to get one's mind around, that the world isn't a grid, just how fluid it is. From your perspective, measured scientifically, it won't be that Alpha Centauri approached you faster than light, it will be that, measured in the middle of your journey, it only was half a light-year away. Even though it never "moved" closer, more like the space between you and the star compressed itself relative to you.

Does that mean you managed to outrun the light? Kinda and kinda not. You see, from light's perspective, time doesn't exist at all - just like in classical optics, light reaches everywhere instantly. Light, radio waves, any wave. So light was still faster from Alpha Centauri to you, it did the trip within planck time. It's only outside observers that have to perceive its instantaneous spread in their own slow time.

[panzereich]

>>> And I once again have to repeat that effectively faster-than-light travel is already well possible, provided an energy source. It's not even hard.

Faster than light speed travel is physically impossible. You cannot simply accelerate and eventually go as fast or faster than light speed.

The closer to C (lightspeed) you travel, the more energy is required to accelerate further. In terms of speed of light, photons have no mass so are able to travel this fast. Anything with mass would require infinite energy to reach speed of light. So in theory speed of light IS A highway speed limit that nothing but massless particles can reach.

A spaceship attempting this kind of lightspeed travel would need to consume more energy than the big bang. Ie Infinite energy.

e=mc2. Energy = mass x speed of light squared. There is pretty much a general consensus on this.

However, it seems the universe is expanding faster than the speed of light. How? This can be illustrated with a balloon. If you draw some dots on a rubber balloon and then inflate the balloon, you can see how this could work, how the space between the dots expands and they grow apart quickly, yet they remain in the same space. By stretching or shrinking spacetime artificially, you could in theory travel lightyears very quickly. Again energy required to do this.

Some of the magic of general relativity is revealed by the fact that gravity and time and linked to create spacetime. Time on the Earth's surface passes slower than if in orbit. Mass is therefore part of the equation and cannot be removed.

Going past Einstein, quantum physics and the latest string theories are somewhat bound with general relativity if more than 4 dimensions are taken into account. Ie height, width, breadth and time. This again can be illustrated by imagining a wire. Imagine an ant crawling on the wire. It can go up and down the wire. Now if we look from a distance, the ant appears to be moving up and down a 2 dimensional line. We cannot see the curve in the wire from a long way away. However, the ant can also go around the wire because it is tiny. From a distance and our perspective, the ant has vanished.

The same applies to our own 4 dimensional space. If we could image 5, 6 or 7 dimensions. Smaller ones bound up in a quantum (really tiny) state that are hidden from our view or perspective. String theory uses these extra dimensions to primarily allow the effect of gravity to integrated. The four forces in our universe are the strong nuclear force (holds our atoms together) weak nuclear force (radiation) electromagnetism and gravity.

Gravity appears to be very weak compared to the other forces. If it wasn't we wouldn't exist. In string theory, this is because gravity or the unknown particles responsible for it (gravitron?), is leaked out of our own 4 dimensions into other smaller dimensions. The strength of gravity is dispersed so it becomes weaker. It leaks, because the particle responsible for gravity is so small no one is able to identify it. It is so small, that it can fit into these other tiny quantum dimensions.

As with Einstein improving the less precise Newtonian model. String theory hopes to improve general relativity and incorporate the quantum world within general relativity. Quantum physics exhibits all kinds of strange properties. Such as particles that appear to interact with each other at great distances regardless of distance. Particles that appear to act like a wave when observed. Einstein called it spooky action from a distance. He hated the way it wouldn't fit within general relativity. In fact it makes many people uneasy.

Once this new model is completed, there will be a much greater understanding of how everything works. Travelling faster than the speed of light is impossible. Travelling to the stars might not be. Getting to places really far away really quickly could become a reality and in turn our butt probing technology would develop at an exponential rate.

[tiger12348]

Not correct. Neither increase in mass nor any slowing down of your clock happen for you. Your time flows as normal, and your speed, calculated as v=dx/dt, where x is your distance from the starting point, measured at the beginning of your journey, will seamlessly reach c, exceed c, and keep growing.

This is not an illusion or failure to notice things. It's as true for you as what the outside observer experiences is true for him. So if dx/dt>c doesn't count as faster than light travel, what does?

The last equation keeps true. And a=F/m where F is thrust. So v=t*F/m. As t grows and a remains constant, what happens to v?

Remember, there is no absolute velocity. No stationary observer - no stationary object at all - only a pair of objects can be stationary relative to one another. You are never actually approaching the speed of light, it's more like objects approaching it relative to you. Think of it this way: you are always in Newtonian space, it only gradually turns Einsteinian for long distances.

Of course, distance itself is relative as well. It's very hard to get one's mind around, that the world isn't a grid, just how fluid it is. From your perspective, measured scientifically, it won't be that Alpha Centauri approached you faster than light, it will be that, measured in the middle of your journey, it only was half a light-year away. Even though it never "moved" closer, more like the space between you and the star compressed itself relative to you.

Does that mean you managed to outrun the light? Kinda and kinda not. You see, from light's perspective, time doesn't exist at all - just like in classical optics, light reaches everywhere instantly. Light, radio waves, any wave. So light was still faster from Alpha Centauri to you, it did the trip within planck time. It's only outside observers that have to perceive its instantaneous spread in their own slow time.

In fact, if your craft is flying away from the sun at 99.99% of c, then the light from the sun will still pass you at c. This is the way that light works. To make sense of this observation , something else has to give, and what gives is time.Time has to run at different rates for different people, depending on how they are moving relative to each other. Also note that the presence of acceleration suggests that your craft is actually "moving“ relative to the earth, and you will indeed experience a slower time relative to the earth. The exact amount is given by dt' = dt/√[1 - (v2/c2)], where v is the relative speed of what's moving compared to that of a stationary observer, dt is the time elapsed by the observer's watch, and dt' is the time that has elapsed by the object that is moving's watch. Furthermore when you picked up the earth as reference for your distance measurement, so you will also have to agree with the clocks running on the earth, this is how you calculate velocity.

In short,time is not absolute while the speed of light is constant... it is a limit, even we do have infinite energy, which is a really big ask, so big that by this fact alone makes the FTL impossible for modern science. In the case of relativity, keep in mind that relativity depends on the speed of light as a universal limit. So as soon as FTL is observed, relativity itself breaks down at that instant, its like trying to prove 1 times 2 equals 3 by using the times table which itself is based on 1 times 2 equals 2.

Edited October 24, 2012 by tiger12348

[smith350]

I'll leave this here.

http://techland.time.com/2012/09/19/nasa-actually-working-on-faster-than-light-warp-drive/

Should be interesting to see where this goes. I'm certainly looking forward to being in a space opera

[TrashMan]

As soon as we see a FTL civilization, they have already broken the universal speed law, or more likely found a way around it. This shows their mastery over the fabric of space-time, and if they are hostile, we don't stand a slight chance.

I tend to disagree.

A hologram won't fool any scientist on the planet, yes. However the point is 3D hologram is an over kill for people who want to believe there is god and after life, which is the majority, turning them against the minority with alien weaponry will force an unconditional surrender.

No. You think religious people are stupid and would turn on their own so easily?

Why would God give them alein weapons to begin with? Why does God need them to fight a war?

And what if they can do some miracle healing:) will that do?

No. It has to be something that breaks some universal, proven laws of the universe. Something that breaks physics.

Since aliens rely on physics just as much as we do, they can't do that.

[TrashMan]

@HWP:

http://www.projectrho.com/public_html/rocket/fasterlight.php

Red Queens Race.

[HWP]

Faster than light speed travel is physically impossible. You cannot simply accelerate and eventually go as fast or faster than light speed. The closer to C (lightspeed) you travel, the more energy is required to accelerate further.

You forgot to add: from an external observer's perspective. From your perspective, you accelerate just as fast as always.

In terms of speed of light, photons have no mass so are able to travel this fast. Anything with mass would require infinite energy to reach speed of light. So in theory speed of light IS A highway speed limit that nothing but massless particles can reach.

Not quite.

If I hold my foot down on a highway till I hit the speed limit, or better till I hit my car's absolute limit, I'll feel my acceleration slow down approaching the top speed and float around zero. Getting to a point 500 miles away will still take me 7 hours, or 3 if I had the fuel to floor it.

But if I "hold my foot down" in space, my acceleration will never slow down. So a 500 light-year trip will only take me 32 years if I accelerate at 1c/year (0.951g) or 10 years if I accelerate at 10c/year.

A traveler not emplopying relativistic means of observation will never notice any "speed of light limit" - measured by conventional means, like speed=distance/time, space will behave as Newtonian for him.

In fact, if your craft is flying away from the sun at 99.99% of c, then the light from the sun will still pass you at c. This is the way that light works. To make sense of this observation , something else has to give, and what gives is time.

Yes. So think some more on it, how and why does that happen, and what that means for you.

Furthermore when you picked up the earth as reference for your distance measurement, so you will also have to agree with the clocks running on the earth, this is how you calculate velocity.

I'm in a spaceship crossing the interstellar space. No stop signs, speed limit, nobody's gonna slow me down.

So what do I care if it's lunchtime in Greenwich or teatime in London?

This might of course become a problem for a British traveler, because he would have to either miss teatime or consume a progressively increasing amount of tea. This is, perhaps, why the first space explorers were Russian and American - vodka and coffee can be enjoyed on your own time.

But seriously speaking, what Einstein's theory is properly called is "relativity of simultaneity". There is no such thing as simultaneous events. You can't simply "agree with clocks on Earth" - to do so would require some form of absolute simultaneity, some signal that lets you synchronize your clocks.

The people on Earth will only see you moving away from them at sublight speed. Well, who cares about them? If you were to return, IRS would run you such a huge backlog in taxes that you'll wish you hadn't.

From your perspective, distance to Earth will be increasing at superlight speed. But it's not because it moves faster than light, nothing does - rather because time on it will run faster compared to yours, so it will fly away like in fast motion. The same for your destination, it will be approaching you in fast motion.

FTL travel is important for space operas that picture space like "suburbia, but big". If you settle on the fact that time in "static" locations will pass faster, the speed of light is not a restriction for the actual traveler.

Back to the subject of the game, if aliens are coming to Earth looking for Lebensraum, not only don't they need FTL, they have no reason to bother with it. They don't care if millennia pass at their home, if they aren't going back anyway, and they certainly care even less about how much time is passing on yet another planet to invade. From the perspective of a space fleet, hundreds of "static" light-years can be easily crossed in just a few of their years without breaking any laws of general relativity.

Red Queens Race.

Et tu, Brute? I hoped at least you were getting how it works. Throwing a page (which I know) for space roleplayers and sci-fi writers at me, seriously?

While true for the context of busting a space opera, it's irrelevant here. You don't need to care about time elsewhere unless you plan on going back. Even then, so what, your hair was going to get outdated either way. The real limitations (fuel aside) are your ship's supply exhaustion, component aging, finally your own lifespan. And these aren't affected. Given enough fuel, you could go across the entire galaxy in your lifetime.

Yes, you'll arrive at points in local time that are hundreds and thousands of years ahead of those observed by astronomers on Earth, but it's not like it even matters, you couldn't match them anyway because of observation delays. It might annoy your potential investors that they'll only get your messages millennia later, but if you're traveling on your dime, it's simply not a concern. Your dime, your time.

It's also not a concern if you are some sort of a colony ship or invasion fleet. For any one-way trip.

Space opera tends to involve hopping on an interstellar bus in the morning and coming back before dinner. That is not going to happen. But for a traveler unburdened by family at home there is no problem of "light speed limit". There are other problems, like fuel reserves, but not this.

[panzereich]

A particle's inertial mass increases as it approaches the speed of light. Hence infinite energy required to get closer to c.

Travel at even remotely close to light speed is only possible in an atom smasher using low mass particles. The problem with the analogy is that your foot is only going to provide finite acceleration. The faster you go, the more you need to push your foot down. Regardless of the so called lack of any resistance in space, there is still the problem of relativity. You will never reach C. You may get close, but having mass, the only way is if you go .51 C and your destination is approaching you at .51 C. Relativity. Not to mention there is always resistance even in the void, as curves in spacetime would create resistance.

The answers are not in gradual acceleration using 'Newtonian' physics, as Relativity is simply a more accurate representation of physics. The speed of light is a finite constant number because it has been measured. Everything else is variable. In itself, its a frame of reference. You simply cannot go at C or faster. Because C is the speed light travels in vacuum. Light which is made from photons which have no mass. So these things can go quicker than anything else. How do you go quicker? Negative mass?

The answer is more about understanding the boundaries or rules, then finding shortcuts. One of these shortcuts presents itself in the fact that our own universe is expanding faster than lightspeed. Like I mentioned before, the balloon scenario. If you can shrink space in front of you and expand it behind you, then technically, for your frame of reference, you achieve 'fake' faster than light.

[HWP]

You may get close, but having mass, the only way is if you go .51 C and your destination is approaching you at .51 C. Relativity.

It doesn't work that way. A single object does not have velocity.

Velocity is a property of the relationship between two objects, not an individual object. The described above doesn't work like that, it would be 0.51c, not 0.51*2.

The answers are not in gradual acceleration using 'Newtonian' physics, as Relativity is simply a more accurate representation of physics.

My post above is not speculation. It's not search for answers. It's cold hard facts.

I'm just explaining something already well known in scientific context.

Speed, time and distance all depend on the frame of reference. Time is individual for every point in space. Distance and velocity are individual for every pair of objects.

Your own velocity, in your personal frame of reference, is always zero. Your mechanical behavior in it is perfectly described by classical physics. Special relativity plays a role in your relationships with objects that are moving relative to you.

Light which is made from photons which have no mass. So these things can go quicker than anything else. How do you go quicker?

You don't. But you see, from light's perspective, i.e. in a photon's frame of reference, its spread around the universe is instantaneous.

Don't believe me? Calculate velocity time dilation for a photon relative to a non-photon. It's t=t'*sqrt(1-c2/c2)=0. A photon has no time, everything happens instantly for it. It can cross an infinite distance instantly (from its perspective). But would that not mean that a photon exceeds c? Think about it.

No, certainly not. How?

Because distance is also relative. In a photon's frame of reference, the universe isn't large at all. As far as a photon is concerned, the size of the universe is zero. And remember, a photon's perspective is as valid as any other, as mine or yours.

The same applies to you. If you keep accelerating towards Alpha Centauri, your relative velocity will never reach the speed of light - but the distance between you and the star, in your frame of reference, will itself become much smaller.

No special technique is needed. Simply apply thrust.

There's also a much longer and more formal general relativity explanation for it, involving spacetime properties. Time dilation is just simpler and as accurate.

[TrashMan]

Et tu, Brute? I hoped at least you were getting how it works. Throwing a page (which I know) for space roleplayers and sci-fi writers at me, seriously?

Seriously.

That page was written by multiple people with PhD's who know the subject matter better than you or me.

While true for the context of busting a space opera, it's irrelevant here.

Physics is true and relevant everywhere.

[HWP]

That page was written by multiple people with PhD's who know the subject matter better than you or me.

I know that page, I know that site, and I happen to provide for my sustenance from, among other things, knowledge of its subject matter (I mean physics, not fiction).

Unfortunately, "written by PhD, read by a layman" doesn't always translate into much. You are severely misunderstanding either that page, or my posts, or both.

If you had the time to read a 100-kilobyte page, please, spend a short amount of time to at least glance across my 2-4 kilobyte posts before claiming that a link you happen to have disproves it. Because, as you will then see, there is no contradiction.

The page refers to the difficulty or impossibility of traveling faster than the speed of light in your source's or destination's frame of reference. Which is the realm of space opera. What I am describing - and it's not some invention I'm pushing, it's textbook physics (only not a high school textbook) - refers to travel time in the traveler's frame of reference.

Since you are probably not going to read any complete paragraph I write, here is another page from the same site: http://www.projectrho.com/public_html/rocket/slowerlight.php#id--Relativity

Just skip to the blue and gray table there.

In case you're intent on ignoring even links I provide, here's part of that table provided for your and other readers' convenience:

[table=width: 500, class: grid]

[tr]

[td]T Proper time elapsed [/td]

[td]t Terra time elapsed[/td]

[td]d Distance[/td]

[td]v Final velocity[/td]

[td]γ Gamma[/td]

[/tr]

[tr]

[td]1 year[/td]

[td]1.19 years[/td]

[td]0.56 lyrs[/td]

[td]0.77c[/td]

[td]1.58 [/td]

[/tr]

[tr]

[td]2[/td]

[td]3.75[/td]

[td]2.90[/td]

[td]0.97[/td]

[td]3.99[/td]

[/tr]

[tr]5 83.7 82.7 0.99993 86.2

[td]5[/td]

[td]83.7[/td]

[td]82.7[/td]

[td]0.99993[/td]

[td]86.2[/td]

[/tr]

[/table]

This is travel at 1g acceleration. Now divide d by T. Notice something?

5 years pass for you. You cover 82.7 light-years. Yes, 83.7 pass for the slowpokes in a place you aren't returning to anyway.

No magic thingamajigs required, all you need is an engine providing a modest 1g of acceleration.

And yes, this is what I've been saying all along. Except I used a 10g engine for my example.

I'm not sure if I know why I even bother. Perhaps it's just that so many people read ten paragraphs (if that much!) about special relativity and think they got it all down, "oh, right, like a highway speed limit, thank you officer". While it's nothing like that, it's time itself that is at the center of this. It just requires wrapping one's mind around a few very counterintuitive things that go against how we normally think of space and time.

And let me repeat that nothing I've posted here is even slightly speculative.

Edited October 24, 2012 by HWP

[TrashMan]

You'll pardon me if I don't trust you on your word.

Anyone can claim to have a PhD in physics.

Also to claim that only the ships/crews frame of reffernece matters is silly.

This is of course, assuming you have an engine capable of providing continous high trust for years....which you don't.

[HWP]

You'll pardon me if I don't trust you on your word.

Which is why I never asked you to. And actually explained things.

Not only that - I never even hinted at knowing more about the subject until the last post, where it was necessary, since you seemed to misunderstand my posts for conjecture or personal hypothesizing rather than statement of well-known and scientifically undisputed facts.

I provided descriptions and explanations consistent with every law of physics as we know it. You had full opportunity to check my every word and look further into it. You still have, I considered it overly condescending to provide textbook/wiki/whatever links everywhere; that level of hand-holding is only appropriate for a Firaxis game or an elementary school.

In the end I provided you a link to the same site that you seem to trust over college textbooks (which is silly, because NR is in fact a mish-mash of pieces of text from 100's of people). Presumably that has satisfied you, since you seem to be now shifting your argument to another frame of reference.

But I stated clearly and repeatedly which frame of reference my posts refer to:

The same applies to you. If you keep accelerating towards Alpha Centauri, your relative velocity will never reach the speed of light - but the distance between you and the star, in your frame of reference, will itself become much smaller.

It's also not a concern if you are some sort of a colony ship or invasion fleet. For any one-way trip.

Space opera tends to involve hopping on an interstellar bus in the morning and coming back before dinner. That is not going to happen.

Mentioned the fuel concerns too. Not that it's a big deal. Theoretical (TRL3+) nuclear rocket designs are sufficient for that, albeit at low payload ratio.

[tiger12348]

No. You think religious people are stupid and would turn on their own so easily?

Why would God give them alein weapons to begin with? Why does God need them to fight a war?

Definetly not stupid, you see, many religious people I know are well educated, perfectly productive members of the society. Actually, I find the ability to turn one's reasoning capacity off for a short period of time when it comes to their belief is well beyond me.

I'm in a spaceship crossing the interstellar space. No stop signs, speed limit, nobody's gonna slow me down.

So what do I care if it's lunchtime in Greenwich or teatime in London?

This might of course become a problem for a British traveler, because he would have to either miss teatime or consume a progressively increasing amount of tea. This is, perhaps, why the first space explorers were Russian and American - vodka and coffee can be enjoyed on your own time.

You actually misunderstood what I mean by agreeing with the clocks on Earth, by clocks I mean how we define a second on Earth. Remember the speed of light is defined by m/s in the SI units.

You forgot to add: from an external observer's perspective. From your perspective, you accelerate just as fast as always

Same thing here, acceleration is defined by m/s/s in SI unit, and your response to this, alone with infinte energy is you don't care, who cares... Sounds really like philosophy to me, science is based on observation with standards, relativity does not mean I don't care, because everything is relative.

Because distance is also relative. In a photon's frame of reference, the universe isn't large at all. As far as a photon is concerned, the size of the universe is zero. And remember, a photon's perspective is as valid as any other, as mine or yours.

It is not zero, it is undefined, I hope you get the difference.

"written by PhD, read by a layman"

Did you get your idea of FTL is possible from Michio Kaku's "Sci Fi science"?

Neither increase in mass nor any slowing down of your clock happen for you. Your time flows as normal.

5 years pass for you. You cover 82.7 light-years. Yes, 83.7 pass for the slowpokes in a place you aren't returning to anyway.

Both quotes comes from you, if you forgot. 5 years pass for you, 83.7 years pass for the slowpokes, yet time does not slow down for you? I finally get how you misunderstood time and clock right here. Don't forget, 83.7 years pass for the slowpokes in a place you want to go as well.

Let's say you and your craft traveling at the speed of light to a distant star system to meet your new girl friend for a date, do you really not care by the time you get there, millenia has past at her prespective? Tell her you got there instantly from your prespective?

I'm not sure if I know why I even bother. Perhaps it's just that so many people read ten paragraphs (if that much!) about special relativity and think they got it all down, "oh, right, like a highway speed limit, thank you officer". While it's nothing like that, it's time itself that is at the center of this. It just requires wrapping one's mind around a few very counterintuitive things that go against how we normally think of space and time.

And let me repeat that nothing I've posted here is even slightly speculative.

Trust me, I really wanted to be serious, but it's kinda getting funny when someone claims to understand relativity inside out fails to get the first paragraph of what the whole theory is based on.

Edited October 25, 2012 by tiger12348

[panzereich]

How do you make a system that outputs more energy than in put into it? You dont.