Is relativity common knowledge?

[Aerozord]

Sometimes things I consider basic I find out isn't well known to people in general.

Yesterday I got into a heated debate with someone about long distance space travel. Two specific things of course came up. First was that as an object approaches the speed of light it takes more energy to accelerate it. Which is because of the second point that mass is energy, which also brought up that there is a set amount of energy within our solar system. Both of which are covered under general relativity.

I seemed to be the only one that knew about that. The reason the debate broke down is because I was trying to give a little physics lesson so they can understand why faster than light travel isn't possible but you know how people get when you do that. Plus the argument devolved into the tired old assumption that we'll just find a way to break the laws of physics because ... science.

Anyways I was just curious was this a fluke or do most people not know of this layer of physics?

[Marc v4.0]

It's relatively common knowledge :cool:

[MuMu]

Nope, I'm afraid I'm completely oblivious about it, but then again I'm a total moron.

[The Artist Formerly Known as Hawk]

A lot people probably don't. But then, a lot of people don't know a lot about science in general anyway, and are amazed by the simplest of things nerds like us take for granted.

Next try explaining to them how time is also affected by relativity and watch their heads explode when they realise that this is an actual engineering problem that we had to overcome to make gps work.

[synkr0nized]

Perhaps for some people the appeal of science-fiction solutions encourages incorrect beliefs about real science.

Maybe one day it wouldn't be fiction, you know?


Otherwise it's likely just a lack of exposure to it. I mean, how often does the average person across the globe have a need to think about and understand relativity or the details of physics involved in space travel?

However I suppose to address the actual question, I would have thought for most people it was "common knowledge" in that folks had heard about it and knew some of the basic details (that's probably all I'd be able to offer without the aid of source materials). But standing back for a second, despite things like The Big Bang Theory enjoying attention in pop culture it's not necessarily something anyone commits to memory beyond whatever science courses in school might touch upon it. I suppose I am hesitant to side one way or the other and would be interested in, say, a survey across a sizable population that asked about a few theories or chunks of science to see what people had or had not heard of before.


@Mumu: You're not a moron at all. I point to what I just wrote above -- you probably just had no interactions with it, or not enough to keep it in your head among all the other factoids in there. I suspect you don't have any difficulty grasping it and would be completely fine reading about it, etc.

not possessing information != being unable to process information

[Red Mage Black]

To my best knowledge of physics, which is general and covers just about every other subject I know in definition, there is nothing that can break the speed of light, as you said. That and the whole Laws of the Conservation of Energy, but I think that begs the question, "How do we actually know how much energy is in the Universe and can it be measured?" You have to not only take into account Stars(dead and alive), but planets, comets, asteroids, meteors, even black holes(which aren't even holes) and break it down to the atomic level.

I'm not sure what this whole "we'll end up breaking physics" thing is about. Frankly, if it was something achievable, then it was already a function of the Universe in the first place. Warp Speed sounds fun, even near light speed sounds good(improbable, but not impossible). I guess the fact you mentioned that people decide to substitute for 'Rule of Cool' is about Mass. The bigger something is, the more energy is required to propel it forward and I don't think we have any source of energy strong enough(or a sufficient amount of) to even propel anything larger than a scooter to the speed.

If anything, the whole "energy cannot be created or destroyed has made me think. When something else 'breaks down', so to speak, the universe finds a completely different use for the energy that is released from it.

Ugh, I think I've rambled on a bit too much now. tl;dr: You're right and our generation is just getting dumber.

EDIT: And I was completely beaten out by Synk, who has a much better explanation of why our generation doesn't have the information.

[Doc ock rokc]

I know the basic guidelines to it but not all of the little idiosyncrasies. Mostly because I am not in a field that regularly uses relativity nor do I have any applicable use for it.

that being said I probobly need to look into it farther to not seem like a moron.

[McTahr]

Relativity doesn't come up until third semester of physics, typically, which is usually only for physics majors and certain kinds of engineers. Unless they're exposed to it through a particular curiosity or a show, it's not really common knowledge even in the sciences. However, those in the sciences are often the kinds of people who will have those curiosities and seek it out themselves.

Everything before that is considered Galilean/Newtonian as far as mechanics goes, depending on what you're doing, which are far more intuitive, but also generally poorly understood by the public as well.

E: I've had to teach it once or twice. Basically, quite a few students are blown away by some of the weirder parts of it because it's weird and entirely new, and some are just "meh" because they sought it out months ago. (I read Einstein's Relativity when I was a wee freshman yet to take a physics course, just out of curiosity.)

EE: Also, when discussing energy, that all really falls under the Conservation of Energy rather than relativity itself. Relativity focuses on proper treatment of the laws of physics in wonky inertial frames and plays with Lorentz transformations and the like.

EEE: I may correct people when it comes to science stuff, but I'm not trying to be a jerk. It is quite refreshing to see members of the general public give half a damn about science. Pseudoscience, new age-y bullshit, and the general tendency to embrace ignorance actually pretty much depress the hell out of me as a scientist.

[Aerozord]

To my best knowledge of physics, which is general and covers just about every other subject I know in definition, there is nothing that can break the speed of light, as you said. That and the whole Laws of the Conservation of Energy, but I think that begs the question, "How do we actually know how much energy is in the Universe and can it be measured?" You have to not only take into account Stars(dead and alive), but planets, comets, asteroids, meteors, even black holes(which aren't even holes) and break it down to the atomic level.

Matter is matter. It doesn't ... err matter, what form its in X amount of mass has X amount of energy. Most of the energy that isn't is heat which is easy enough to measure. So we can ballpark this decently.

I'm not sure what this whole "we'll end up breaking physics" thing is about. Frankly, if it was something achievable, then it was already a function of the Universe in the first place. Warp Speed sounds fun, even near light speed sounds good(improbable, but not impossible). I guess the fact you mentioned that people decide to substitute for 'Rule of Cool' is about Mass. The bigger something is, the more energy is required to propel it forward and I don't think we have any source of energy strong enough(or a sufficient amount of) to even propel anything larger than a scooter to the speed.

Its hard to explain that part of the argument because its based on differing mindsets. I guess you can sum it up as this.

Me: While we dont understand everything about physics, we understand enough to know you cant go faster than light.

Them: We dont currently know how to go faster than light, but someday we will.

What bothers me personally is I hate this mindset that everything is an eventuality even if science says its flat out impossible.

[Flarecobra]

From my encounters, even among my Astronomy classmates in college... it seems that lots of folks know OF it, and of the e=mc^2 equasion, but not the mechanics of it.

[Sithdarth]

To my best knowledge of physics, which is general and covers just about every other subject I know in definition, there is nothing that can break the speed of light, as you said.

Actually what special relativity says (or rather what is disallowed by the mathematics) is specifically anything with a non-zero rest mass traveling at precisely the speed of light in a vacuum in flat spacetime. Which means nothing with a rest mass and a speed less than light in flat spacetime will go above the speed of light in that flat spacetime and nothing with a rest mass and a speed greater than the speed of light in flat space time will go below the speed of light in that flat spacetime. This is why tachyons are still sort of a thing.

However, when you start throwing general relativity in the mix and start working with non-trivial spacetime geometries things get much more difficult. Basically put if you can construct a section of spacetime that has a velocity with respect to other nearby spacetime of say 0.5c and then fly a spaceship through that moving spacetime region in the same direction as its velocity with a velocity of say 0.6c than people in the "non-moving" spacetime will see the ship has having traveled faster than the speed of light. These types of spacetimes admit closed timelike curves and thus travel to the past.

Further reading:
Closed Timelike Curves (http://en.wikipedia.org/wiki/Closed_timelike_curve)
Kerr Metric (http://en.wikipedia.org/wiki/Kerr_metric#Features_of_the_Kerr_vacuum)
Tippler Cylinder (http://en.wikipedia.org/wiki/Tipler_cylinder)

Then of course there are also warp metrics which are a bit different. Some reading:
Alcubierre Drive (http://en.wikipedia.org/wiki/Alcubierre_drive)
White-Juday Warp-field Interferometer (http://en.wikipedia.org/wiki/White%E2%80%93Juday_warp-field_interferometer)

And of course there is always wormholes.

General wiki page on FTL:
Faster than light (http://en.wikipedia.org/wiki/Faster-than-light)

So will a spacecraft ever go faster than light with respect to its locally flat spacetime? No that isn't going to happen. However, it might go faster than light with respect to at least some "distant" observers but definitely not by reactionary propulsion schemes.

[Nique]

Time-dilation confuses people pretty often, I've found. If they're really going at it from a wishful sci-fi angle, just tell them that a warp engine only works by skipping physics altogether.