Headlights in FTL

[Lendri]

No. Light can not travel slower than c. Any time that you think it does, it is simply not traveling in a straight line and that gives it the appearance of traveling slower but it is still traveling at c.

The idea that light only appears to slow below c because it's zigzagging around or bouncing off particles (or being absorbed and re-emitted) when travelling in a medium doesn't quite work out. If light behaved like this then it would always diffuse through the medium because it doesn't "know" what direction it's "supposed" to be travelling in, and wouldn't therefore return to the "correct" direction every time it interacted with a particle from the medium. Water would look like frosted glass - you wouldn't be able to see a light source on the other side of a tank of water or block of glass if light behaved this way, and fibre-optic signals would be scrambled. Light would behave this way if it were only made of particles, but it's a wave too. Light travels more slowly through a medium than a vacuum because the wave's electric field is pushing the electrons in the medium around as it barges through, and the speed at which it travels through the medium is dictated by how much the electrons resist being moved, which is (broadly speaking) a property of the density of the medium.

 

[DragoonKnight]

Getting off topic now, but I'm genuinely curious:
According to https://en.wikipedia.org/wiki/Cherenkov_radiation, "the speed of the propagation of light in water is only 0.75c." Also, according to http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/speed_of_light.html, "Light is slowed down in transparent media such as air, water and glass."

I read that as light traveling below c in different media in non-vacuum?

light in a medium is forced to bounce off the atoms / molecules of that medium. It is not traveling in a straight line.
I think you simply stumbled on a very general explanation and that is ok for most cases, but a detailed explanation has to cover what actually happens in a medium.

 

[Luponator]

light in a medium is forced to bounce off the atoms / molecules of that medium. It is not traveling in a straight line.
I think you simply stumbled on a very general explanation and that is ok for most cases, but a detailed explanation has to cover what actually happens in a medium.

Oh I see. You mean that light bounces 'around' atoms on it's path through say water, and therefore can't take the direct route as it could in a vacuum. Thanks!

 

[Lendri]

Oh I see. You mean that light bounces 'around' atoms on it's path through say water, and therefore can't take the direct route as it could in a vacuum. Thanks!

This is not the case. See my post above.

 

[DragoonKnight]

The idea that light only appears to slow below c because it's zigzagging around or bouncing off particles (or being absorbed and re-emitted) when travelling in a medium doesn't quite work out. If light behaved like this then it would always diffuse through the medium because it doesn't "know" what direction it's "supposed" to be travelling in, and wouldn't therefore return to the "correct" direction every time it interacted with a particle from the medium. Water would look like frosted glass - you wouldn't be able to see a light source on the other side of a tank of water or block of glass if light behaved this way, and fibre-optic signals would be scrambled. Light would behave this way if it were only made of particles, but it's a wave too. Light travels more slowly through a medium than a vacuum because the wave's electric field is pushing the electrons in the medium around as it barges through, and the speed at which it travels through the medium is dictated by how much the electrons resist being moved, which is (broadly speaking) a property of the density of the medium.

You do have refraction, reflection, absorption, and remission taking place. You are wrong in denying that these phenomena take place. There is a reason the term propagation velocity is used when we are talking about the speed of light in a medium. The photons themselves never actually slow down. You know what, here... Let two people far smarter than me explain this to you

https://www.quora.com/Can-a-photon-...-than-the-speed-of-light-in-vacuum-conditions

scroll down and read what the two guys with a PhD in physics have to say.

 

[The space tyrant]

Hi, you are employing wrong sciences here.

Firstly, nothing can travel faster than light, it's simply not allowed by this universe (maybe there are universes that do allow it but not this one)

A photon (that does travel at the speed of light) when born is immediately transported to it's destination , that is the speed of light.

Let me elaborate, when a photon is born in our Sun, everything and everyone in the universe will agree that the photon is taking time, or traveling untill it reachers earth and get's absorbed for example on your face, warming you on a sunny day.

Same thing with photons that are born in the other side of the galaxy which are currently taking thousands of years to reach us, THE OBERSERVERS, judging by our point of reference.

But, for the photon, it's life span is completely different. It is born on the other side of the galaxy, and is absorbed by it's destination (for example your face)
immediately.

Therefore, not only it is not possible to travel faster than light, a statement "faster than light" is a logical fallacy, it's almost the same as saying "faster than the speed of 3 Isaac Neutons divided by 7 Conan O'Briens", it's as gibberish sentance, as you cannot build a craft from particles that don't even exist for longer than a split moment.

Theoreticly it's even impossible to build a craft that will travel at the speed of light. (however on paper i think it still possible to reach something like 99,99%, don't quote me on this as I do not remember now)

However, there is a way to cheat this, by employing Alcubierre's Drive theory, which is not technicly fictional as it has been proven on paper (the same way that Black Holes were proven years ago but were considered fictional untill their discovery by LIGO in late 2015)

Alcubierre drive theory states that you can build a craft with an engine that uses energy to contract spacetime itself ahead of the craft while expanding it behind the craft :

http://vignette4.wikia.nocookie.net...Diagram.jpg/revision/latest?cb=20140720154927

Allowing the craft to ride the wave of spacetime (as if a surfer would employ a surfboard to ride the ocean wave) and achieve superluminal speeds.

However, here's the interesting bit, the spacetime within the warp bubble would remain unchanged, therefore technicly the craft itself would not be traveling faster than light, even though the bubble itself would be, so yes you can have your headlights shining without the need of breaking the laws of physics.

Nah man, that's wrong

 

[Lendri]

Hm. I didn't meant o deny those things were happening, but I've read some convincing sources arguing against the common understanding that light is just bouncing around inside the medium - the process they described is happening as well, meaning that the light really is travelling slower than c. Maybe I was too convinced.

 

[Ian Phillips]

Nah man, that's wrong

Well call me gobsmacked, I didn't know we had a second world class physicist in our midst!

Care to explain exactly how its wrong?

 

[xondk]

Technically (I do like posts that start with technically) c is not "the speed of light". c is the "cosmic speed limit", that is, the fastest speed at which matter/information can possibly travel in the universe (in a vacuum, that is). There's nothing special about light that means nothing can travel faster than it - light travels at c because nothing can travel faster than c. Hypothetically, light would travel at infinite speed if it could. Interestingly it's possible for particles to travel faster than light can in dense media like water (see Cherenkov radiation). Such particles are travelling faster than light in that medium, but are still slower than c.

I realise this is a troll post (when did immersion become a dirty word? Who actually doesn't want games to be immersive?) but hey, teh sceince.

See the problem with stating it is a speed 'limit' because, black holes exist, we have absolutely no idea, only theories on what happens beyond the event horizon of a black hole, but gravity is preventing light from escaping, meaning light takes a bow to gravity. What that means, how it works physic wise, is a gigantic question, but it means something is 'more' then light, add quantum mechanics, and yeah, the best thing we can 'really' say above c, is that "nothing we know, can travel faster then light" given what we do not know about black holes and quantum mechanics though, who knows.

However, there is a way to cheat this, by employing Alcubierre's Drive theory, which is not technicly fictional as it has been proven on paper (the same way that Black Holes were proven years ago but were considered fictional untill their discovery by LIGO in late 2015)

Alcubierre drive theory states that you can build a craft with an engine that uses energy to contract spacetime itself ahead of the craft while expanding it behind the craft :

http://vignette4.wikia.nocookie.net...Diagram.jpg/revision/latest?cb=20140720154927

Allowing the craft to ride the wave of spacetime (as if a surfer would employ a surfboard to ride the ocean wave) and achieve superluminal speeds.

However, here's the interesting bit, the spacetime within the warp bubble would remain unchanged, therefore technicly the craft itself would not be traveling faster than light, even though the bubble itself would be, so yes you can have your headlights shining without the need of breaking the laws of physics.

Yup it is an insane thing, and it might just work, the question is though how would you represent a '3d' wave to someone perceiving it with 3 dimensions.
Waves as we know them and as they are represented on the picture is for people to be able to understand the concept, but are only representing a 2d wave of a plane.

 

[Saipher]

I actually didn't know there was a lore justification for FTL travel. I always thought it was a necessary sacrifice for the multiplayer enviroment. Thanks for that information

 

[shoom]

............

 

[The space tyrant]

............

So how would it look to am outside observer?

 

[MassiveD]

So how would it look to am outside observer?

What would?

 

[Badben]

So there I was, playing the game, minding my own business in super cruise... I had a very long supercruise trip to a nearby star. The ETA display in this game doesn't really work so even tho I didn't know exactly how much time to the other star, I knew it was going to be a while.

Anyways, I decided to use the 'classified camera' and watch my ship warping around from the outside... when I was 'in front' of my ship looking back into the cockpit I realized my headlights were on.

Wait a minute... headlights? My ship was traveling at roughy 50c and climbing at this point, how the heck is the light from my headlights accelerating faster than my ship to reach my 'classified camera'?

It was at this moment that my immersion was shattered. FD can't even get basic physics right. Please fix this so I can play the game.

Thanks.

You need to understand certain properties of light to know that this is exactly how headlights would behave regardless of your own speed. It's far too complicated for me to really truly understand, I'm not really sure anyone understands it truly, but it is a fact that regardless of what speed you are moving, light that you shine away from you will always travel away from you at the speed of light.

Think about it this way, you are actually always stationary in the universe, when you change your location, it's not actually you moving, but the entire universe is actually moving around you. When you move faster, it's actually the universe moving faster around you, are always stationary. Now, understand that light isn't affected by the universe moving around it, when a beam of light is shone, the the universe flying by you has the same affect wind would have on light, that is to say, none. So, if you are always stationary, when you shine a light, it will always move away from you at the speed of light, regardless of whether you are "moving", or what speed you are moving at, because you aren't really moving, the universe is actually moving around you.

this is a good video that explains this, and Einstein's theory of relativity. https://www.youtube.com/watch?v=ev9zrt__lec

 

[Panticus]

It is very simple. Einstein's SR clearly states that your velocity has no effect upon the physics you observe, including the velocity of light.

At light speed, the light from headlights will still go at light speed measured from your frame of reference. This light will also travel at C from anyone else's frame of reference.

Galilean addition of velocities does not apply. The total speed observed w, is not u + v. It is (u + v)/(1 + v^2/c^2)

That is the definitive answer. Mods close thread.

 

[MassiveD]

It is very simple. Einstein's SR clearly states that your velocity has no effect upon the physics you observe, including the velocity of light.

At light speed, the light from headlights will still go at light speed measured from your frame of reference. This light will also travel at C from anyone else's frame of reference.

Galilean addition of velocities does not apply. The total speed observed w, is not u + v. It is (u + v)/(1 + v^2/c^2)

That is the definitive answer. Mods close thread.

Even tho this statement is correct, however it's not related to the thread , as in OP's scenario there are different physics in place as the ship itself is not moving at superluminal speeds.

"Supercruise uses the ship's Frame Shift Drive to compress space in front of a ship and expand it behind a ship, essentially moving space around that ship. This negates any time dilation, as the ship is always travelling less than the speed of light relative to its "frame" of compressed space."

This is the official statement from ED wiki, so they are in fact using Alcubierres Theory to power FSD's.

However the thread should be closed now still, as the quetion was already answered multiple times, and since OP is a known troll

 

[The space tyrant]

It is very simple. Einstein's SR clearly states that your velocity has no effect upon the physics you observe, including the velocity of light.

At light speed, the light from headlights will still go at light speed measured from your frame of reference. This light will also travel at C from anyone else's frame of reference.

Galilean addition of velocities does not apply. The total speed observed w, is not u + v. It is (u + v)/(1 + v^2/c^2)

That is the definitive answer. Mods close thread.

Don't be so sure. A famous physicist once said "If you fully understand quantum mechanics, then you don't really understand quantum mechanics."

There's no definitive answer when hypothetical are involved

 

[MassiveD]

Think about it this way, you are actually always stationary in the universe, when you change your location, it's not actually you moving, but the entire universe is actually moving around you.

[video=youtube;aRDOqiqBUQY]https://www.youtube.com/watch?v=aRDOqiqBUQY[/video]

 

[Panticus]

Don't be so sure. A famous physicist once said "If you fully understand quantum mechanics, then you don't really understand quantum mechanics."

There's no definitive answer when hypothetical are involved

Yep, that was Feynman. Your point being?

- - - - - Additional Content Posted / Auto Merge - - - - -

https://www.youtube.com/watch?v=aRDOqiqBUQY

Yep, a reference to Mach's ideas, which Einstein had some sympathy with. Relevance?

 

[MassiveD]

Don't be so sure. A famous physicist once said "If you fully understand quantum mechanics, then you don't really understand quantum mechanics."

There's no definitive answer when hypothetical are involved

You know whats the saddest thing here, it's not that your life left you to be so lonely that this is the only way you can get your kicks, the saddest thing is that 2 days of free lessons and you still haven't learned a god damn thing.

In this time we could have tought a flat-earth believer that the earth is round, and tought science to a teologist

however, against all odds, you do you my son