/sci/ - Science & Math

You run forward by your reference frame within the vessel. By someone observing from outside it, your speed still wouldn't be at or above that of light.

this has always bugged me

bump for interest

>>1757009
>Nothing can exceed the speed of light.
Says who? Just because we couldn't detect it doesn't mean it's impossible

>>1757009
First: 99.999% the speed of light from what reference system?

Second: You are dead long before, either by the acceleration or by the time it takes to get so fast.

>>1757035
The vessel is travelling at 299 792 457.9999999 m/s.

Let's assume that this is set in the future, science has advanced to the point at which we are able to create a vessel that will carry humans at the speed of light without risk.

http://en.wikipedia.org/wiki/Velocity-addition_formula#Special_theory_of_relativity

>>1757009
>Nothing can exceed the speed of light.
Tachyons!

time will actually slow down to prevent you reaching greater than the speed of light (according to stephen hawking).

http://www.wolframalpha.com/input/?i=[(299792457.9999999+%2B+10)+/+(1+%2B+(299792457.9999999*10)/(29
9792458)^2)+*100000m/s]+/+(speed+of+light+*1000)

>>1757056
Pffft, what does he know, he's in a wheelchair for Christs sake!

http://www.youtube.com/watch?v=3zrGkiPJn5s&feature=related

>>1757058

/thread

ITT: NOT ONE SCIENTIST, SO WHY THE FUCK ARE YOU PEOPLE HERE?!

If you don't understand relativity.. good god.

You CAN'T run forward is the correct answer. The energy your muscles exert is not sufficient to carry you forward.
Remember kids, kinetic energy(motion) has mass. A moving object weighs more than a stationary one.

Eventually, you and the ship weigh so much, that to get another mph would take more energy than the universe contains. That is the speed of light, as only pure energy can move at that speed.

>>1757025
Thats who, retard.

>>1757070
Do YOU understand relativity?

According to the ICS of the person and the vessel, they have velocity zero, so of course he can run forward you cock. He wouldn't be able to do it while the craft was accelerating, but nothing about acceleration is mentioned here.

Energy is relative.

>>1757056
But slower time would mean our neurons worked more slowly too, so we would percieve time normally. .

99% speed of light, at 1/2 speed = 198% speed of light at normal speed time! However our normal speed of time would be a lot slower than the rest of the universe, so to them we'd still be going 99% lightspeed.

>>1757009
>Nothing can exceed the speed of light.

This is bullshit. SR doesnt say this, it only syas that somthing going slower then the speed of light can never exceed it. It also says that somthign going faster then the speed of light can never go slower then the speed of light.
Get your facts straight little guy.

\thread

>>1757116
>it only syas that somthing going slower THEN the speed of light can never exceed it. It also says that somthign going faster then the speed of light can never go slower then the speed of light.


haha
oh wow

u dumb

>>1757123
So you dont know SR then?
GTFO troll!

>>1757123
faggot detected

>>1757070
>Remember kids, kinetic energy(motion) has mass. A moving object weighs more than a stationary one.

That's wrong in so many ways...

>>1757129
You don't know how to spell or use words correctly

>>1757129
>>1757133

so much samefage it hurts.

>>1757143

testing: <span class="math"> x^{2} [/spoiler]

>>1757143
>>1757142
talking about samefags...

>>1757142
Fucking faaggots? in my /sci?

>>1757148
talking bout timestamps...

Travelling faster give you and your ship more mass, which in turn causes time to pass more slowly in the ship.

To an outside observer looking inside your ship from his reference point where time passes at a normal rate (if it were possible) you'd be running really really slowly towards the front of the ship. I assume you'd be running at a speed less than the difference between the speed you ships travelling at and the speed of light so for this stationary observer, your speed is less than the speed of light (he'd see you running in slowmotion).

From your point of view you'd run at normal speed to the front of your ship and everything outside the ship would be happening really quickly.

Don't forget everythings relative. If you turned the headlights of the ship on and measured the speed of the light moving away from you it would measure 300,000,000 m/s even though you know you're travelling forward at almost that. The stationary observer would see the light moving at 300,000,000m/s away from your moving ship.

>>1757148
>>1757009
samefag

nothing with mass can reach the speed of light.

so, lets invent a device that reduces the mass of a spaceship to zero or negative values.

>>1757155
>Travelling faster give you and your ship more mass

NO, this is incorrent. Way to study out of date physics.

>>1757088
>>1757088
http://www.youtube.com/watch?v=gvdf5n-zI14

>>1757155
Sorry I'll clear that last bit up:
>The stationary observer would see the light moving at 300,000,000 m/s towards him.

>>1757155
>Travelling faster give you and your ship more mass

No.

>>1757160
I'll take that as a nope, you don't understand special relativity.

>>1757159

Bring me up to date?? Everything else I said holds, its just the reason I gave for the time difference is apparently wrong :\

>>1757155
>I assume you'd be running at a speed less than the difference between the speed you ships travelling at and the speed of light so for this stationary observer, your speed is less than the speed of light (he'd see you running in slowmotion).
It doesn't matter how fast. He could be riding a mini-rocket within the rocket. Velocities aren't just additive when you get fast enough, and you can't ever reach or pass c.

At least nobody has made an argument that length contraction would shorten the rocket and you wouldn't have room to run.

Pretty simple. As the person trys to run he feels and see's himself run at normal speed. TO an outside observer who can see his capsule movie close to the speed of light the person appear to move extremely slowly due to time dilation. As the capsule gets closer to the speed of light the person gets slower. This has the effect of the person never being able to reach the speed of light.

>>1757169
bump, I was under the impression that this was also the case. What with the airplane and clocks thing.

So uh, does the probability field of a particle get compressed in the direction its travelling?

>>1757169
The idea of a "changing mass" is very very old and outdated. We now say the "mometum" changes, not the "mass".

The time dilation doenst come from the "momemtum change of the object". The time dilation is a direct result of the speed difference of the differnt reference frames involved (momentum change is a result of this as well). It is all a result from the moving reference frames, nothing more.

If you are going 99.9999% the speed of light and move foward alittle you will be going alittle faster, but you will never reach the speed of light. Velocities do not add linearly in SR.
I cannot just directly add the velocities like that, the new "formula" to calculate my new velocity is more colmplicated, and prevents me from reaching the speed of light.

>>1757197
>We now say the "mometum" changes, not the "mass".

Pardon me, but sayng the momentum changes with speed seems alittle obvious? What are you saying that people measure the momentum differently depending on their frame of reference?

Or maybe that they measure the momentum to be the same but the velocity to be different? (That would explain the mass change).

Confused

>>1757197
Given that momentum is velocity times mass, it's obvious the momentum changes if the velocity increases.

For those interested, there are two kinds of mass in special relativity. One is the invariant mass, sometimes called rest mass, which is the same in all frames of reference. The other is the relativistic mass, which is an increasing function of velocity. But the increase in mass is not a property of the object travelling, but due to a change in the geometry of space time.

>>1757249
>people measure the momentum differently depending on their frame of reference?

Yes, of course.


>(That would explain the mass change).

There is no mass change. Mass is a fundemental identifier, it defines what the object is. If Masses changed the identity of the object would change. Mass does not change.

>>>1757272

>Given that momentum is velocity times mass

Stoped reading. That is wrong. That is the very very simple "approximation" for certain very basic physics systems. That defintion isnt the one used in anything but shit teir physics.

>>1757284
>YOU GUYS AREN'T AS SMART AS ME
>WHY HAVEN'T YOU LEARNED ENOUGH PHYSICS SO YOU CAN DISCUSS THINGS WITH ME
>BY THE WAY, I'M POINTLESSLY POSTING PRETTY TERRIBLE PORN JUST FOR THE ATTENTION

>>1757272
>relativistic mass

Wow, how is that 1900 physics working out for you. No physicst uses "relativistic mass" anymore. It is not taught, or used by any serious scientist. The concept ot "relativistic mass" did nothing but confuse people, amnd lead them to fault assumtions about physics (ie thsi thread).

>>1757293
>IM A FUCKING FAGGOT
>I GET INSECURE THAT IM A DUMBASS
>I GET MAD THAT PEOPLE KNOW MORE THEM ME

>>1757293
>>1757299
Back into the shitter you go, /sci/. The sun is almost up.

>>1757297
That is definitely not true.

>>1757308
Name one modern physics textbook that still uses the concept of "relativitic mass"?

nothing will happen. its the same as driving a car at 100mph and switching headlights on. the light is travelling faster than the acual speed of light

safe for work assholes

>>1757070
LMAO retard.

>>1757249
>What are you saying that people measure the momentum differently depending on their frame of reference?
LOL, obviously. In the frame of reference of the "moving" object, the momentum is zero.

http://www.wolframalpha.com/input/?i=add+velocities+0.99c%2C+0.2c

>>1757312
Anything by Wolfgang Rindler for a start

>>1757070
He can run forward

He is still traveling 3000 m/s slower than light speed.

>>1757315
get a better job dumbass

>>1757335
you're an idiot.
stop posting (shit tier) porn. this is a sfw board.
i browse at home and have small children walking about.

if I wanted porn I'd go to /s/ or just to youporn or something (who even faps to stills these days)

inb4 you're fucking cool because you don't care about rules.

fight the power man

You would travel at 99.9991% the speed of light

>If I am on a vessel traveling at speeds equal to 99.999% of the speed of light, and I RUN FORWARDS, what happens?

nothing. no fucking way your fat ass can run at .001 C

>>1757342
>implying that's what he said
>implying ANYONE can run at 186 miles per second.

>>1757335
there are boards for your porn. Go there.

>>1757342
He meant to say 99.999...% of c

>>1757350
Nope, I think I'm gonna post more here. Everyone seems to be fine with it but you.
By the way what is your job? You at some conservative church or somthing?

>>1757362

HURR DURR IM AT A JOB WHERE THE BOSS LETS ME LOOK AT BEWBS

IM FUCKING COOL

fight the power man

>>1757350
porn? what porn?

>>1757197
Semantics are bad and you should feel bad.
That anons point was valid, even if the terminology he used was outdated.

Since you would be moving at 99.whatever% the speed of light you would not be able to move at all within the ship, because, as has been stated, your momentum would be too great.

>>1757369
Your momentun would be zero in your own ICS you idiot.

lrn2SR

>>1757365

I make my own hours and can do my work from anywhere, and pretty much have no boss. I barely use my office at all.

It is called a fucking education, it provides you for more money and flexibility in life. You should have gotten a real degree instead of just beceome a shitty 9-5 engineer. Have fun in your cubical wage slave.

>>1757365
jus 4 u

You stop when you get to the front of the vessel. That's what happens you dumb bastard.

>>1757385
you are an actual idiot.
I'm a grad student.
You obviously got a shitty BA somewhere, couldn't get a real job and now are self(un)employed

>>1757396
>>1757396
BIT TITS IN YA FACE

If you can barely pull yourself forward in a car going forward at 100 mph, what makes you think you'll be able to do it at all on a ship going over 186,000 mph?

>>1757407
Are you trying to do 0 - 100 in 5 seconds or something?

>>1757407
That's because of acceleration you idiot, not because the car is going 100mph, but because it is accelerating to it.

Ever walked on a moving train? You must have legs of steel son.

>>1757406
Has hundreds of shit tier porn pics saved on hard drive
confirmed for virgin

everything is relative to the observer dude. so from ur point of view u r just traveling normally through the space craft.

there is no absolute point of reference for speed, there is only in reference between 2 objects

>>1757406
Holy moly check out the size of the chromatic aberration on that one.

>>1757415
Does like BIG TITTIES IN FACE?
Confirmed faggot (engineer)

>>1757411

Yes, but his ship MUST be accelerating to these speeds, because once the ship reached even close to that speed, it would begin to exhibit several sorts of theoretical phenomena that would make he and his ship unrecognizable.

>>1757436
NO.

Speed is ---relative---

The ICS could be on an neutrino travelling at 99.999% the speed of light away from the ship.

This is a perfectly plausible question in SR, the OP makes no mention of acceleration

>>1757436
No, he and his ship would behave completely normally, no matter how fast it is moving relative to other things. This is the whole basis of relativity. That physics works the same regardless of your inertial frame of reference.

So the answer is?

>>1757479
tits of course or why are you in this thread?

>>1757452

Exactly.

It is theoretically possible to be on a vessel going going at 99.999% of the speed of light relative to the Earth, while RUNNING on that vessel at 99.999% of the speed of light relative to the vessel. And yet, relative to each observer (people on the ship, the person running, and people external to the ship) no one is moving faster than the speed of light, and the speed of light is constant.

In summary: Einstein, bitch.

>>1757450

>an neutrino
>ICS

When an object with mass approaches the speed of light, it converts into energy. He will no longer be a 'he', and there will be no ship.

i'm no scientist, but if you are on a vessel, any vessel, then whatever you are doing is relative to the 'vessel' you're in. if you are on a train traveling 70mph and you run along one carriage at 10mph, you aren't, by your logic, running 80mph.

that..is foolish

>>1757496
What are you talking about?

THE SHIP HAS ZERO VELOCITY RELATIVE TO ITSELF.

You can take a frame of reference (an Inertial Coordinate System) so that the ship is moving with velocity 0.99999c. The ship feels nothing and is not changed in anyway, it still thinks it has zero velocity.

sure is first year nat sci in here

>>1757496
Raj why are you even arguing, you evidently have no idea what you are talking about.
I never understand why people do that.

>>1757009

Time dialates.

>>1757496

on the other hand, considering relative velocity
2 particles are moving towards each other, bith with the speed of light
from one particles perspective, what speed is the other moving at?

You'd think 2xthe speed of light
but it's not =|
because nothing can go faster than the speed of light

oh shiiiit

>>1757523

I'm arguing so that I can better understand this concept, perhaps? God forbid I get involved in a discussion to improve my knowledge.

>>1757505

So then if nothing happens to the ship at 0.9999c, why can't it reach >1c?

>>1757534
From particle As perspective, particle A is still, and particle B is coming at it lightspeed, right? And vice versa.

>>1757538
Dont argue bullshit you just make up faggot!
If you dont know somthing, ask a question! DONT MAKE UP BULLSHIT!

>>1757538
The ship travelling at a velocity of 0.9999c and the ship accelerating to 0.9999c relative to a frame in which it initially had zero velocity are 2 entirely different things.

>>1757544

See, I've never been able to take a class on physics of any sort, so I can only get my knowledge from books and documentaries. As far as I've learned, if a mass approaches the speed of light, it converts into energy. If it's bullshit, then you should speak with the channels that run these documentaries.

How do I know it's bullshit until someone tells me it's wrong? I don't, and so it requires someone to come along and show me that it is bullshit (but must give me reasonable belief for such a hypothesis) and then I shall inquire as to what, exactly, is the truth.

>>1757544
making up bullshit shows you where a persons beliefs already are, so you know where they are coming from. If you know what you're talking about, and you're right, it should be easy for you to prove them wrong/correct them. But you're just resorting to calling him a faggot, so that shows how confident you are about your knowledge.

>>1757550

How did this ship get to traveling at 0.9999c without accelerating to this velocity from zero velocity relative to it's frame?

>>1757552

protip: ditch popsci and documentaries and pick up a textbook.

.

If I had a spinning disc on the ship and I put a stop watch on the disc. As I look down on the disc at the watch I see the watch tick slower as it is moving in the direction of the space ship travel, and the watch ticks faster as it moves in the opposite direction to the ships travel.

>>1757557
He didn't. You are getting confused.

In order to define velocity, we need to choose a frame of reference.

For example, if I wanted to find the velocity of my kicking of a football, I would pick myself as the frame of reference.

In this frame of reference I have zero velocity, and when I kick the ball I say it has a velocity of, say, 20m/s.

But that particular frame of reference I chose is arbitrary. I could have chosen the centre of the solar system as the frame of reference. In this one, I (person kicking the ball) has a velocity of thousands of kilometres a second. But in my own frame I still have zero velocity.

In OPs problem, we can take a frame of reference as being the vessel. As long as it is moving with uniform velocity at the said speed (not accelerating anymore), then in the vessels reference frame it has zero velocity.

It's like being on a train with no windows, if it is moving at a constant speed and not moving, you can't tell it is moving at all.

>>1757574
> and not moving

I meant no shaking, as in it's moving perfectly smoothly

>>1757574

Okay, I get the whole analogy with the kickball; that makes sense.

I also understand that he himself on the ship will not be moving very fast at all, relatively.

However, let's choose any arbitrary point along his travel. From that point on, say his ship is traveling at 0.9999c relative to that point. Is he and his ship moving at 0.9999c relative to a point on the other side of the universe, or faster than 0.9999c relative to that far away point, or slower than 0.9999c relative to that far away point?

>>1757558

I'm currently reading "Quarks: The Stuff of Matter" by Harald Fritzsch. I realize that it is from 1989, but my college is a city college, and very weak in book selection.

>>1757574
Soooo what things ARE absolute, regardless of reference frame?

>>1757577

I understood. :P

>>1757584
Only speed of light.

>>1757583
>However, let's choose any arbitrary point along his travel.
You're implying he's moving in some kind of absolute way. He doesn't need to travel anywhere, depending on which reference frame we choose.

Say I stand still on my chair at the side of a railroad. In my reference frame I haven't "travelled" so there are no "points along my travel". Whereas in the reference frame of a passing (confused) train, moving at uniform velocity, I _am_ moving.

So did I travel, or did I not?

>From that point on, say his ship is traveling at 0.9999c relative to that point. Is he and his ship moving at 0.9999c relative to a point on the other side of the universe, or faster than 0.9999c relative to that far away point, or slower than 0.9999c relative to that far away point?


I think you should read this and restate your question

http://en.wikipedia.org/wiki/Inertial_frame_of_reference

>>1757604

You keep telling me that a motionless object isn't traveling because something else traveling by it could see it as moving away at from them, seemingly in motion.. but the ship isn't motionless. Your chair besides the train is motionless, your body from the kickball is motionless (or at least, motionless for all intensive purposes), but the ship IS in motion.

I'm not saying you're wrong, I'm just inquiring further.

>>1757621
Did you read the article?

Motion is relative. It doesn't make sense to say I was or wasn't moving unless you state which reference frame with respect to.

Pretend there's two man sized space ships floating around with uniform velocity in space. A man in each with a window to look through, moving towards eachother.

Each could say that they are still and the other one is travelling towards them. There is no physical test either could do to determine whether or not they were still and the other was moving.

There is n

>>1757631

I did give a reference frame, though. Say the ship starts on Earth; can we not use Earth as a reference frame? The ship then (somehow) gets to the speed of 0.9999c traveling away from in Earth (in whatever direction you please).

(I did read most of it. I'm getting from it the same thing I'm getting from you, unfortunately.)

>>1757621
>intensive purposes
hee hee

Anyway, remember that the Earth is rotating and orbiting the Sun, which is moving through the galaxy. So the chair near the train isn't motionless completely, it's just motionless with respect to the Earth.

Somebody standing on the train is motionless with respect to the train. Similarly, the train is motionless with respect to them.

The train might be moving at 100km/h past the chair, with respect to the Earth... or the chair. But with respect to a person on the train, or the train itself, the chair is moving in the opposite direction at 100 km/h and in fact the whole Earth might be shifting beneath them.

We know this isn't really the case. The ground doesn't move beneath the train because we'd all feel it. But if you were sitting in space, watching everything move, you'd see the Earth travelling and the chair travelling along with it, and the train travelling 100 km/h away in some direction. From space-guy's perspective they're all definitely moving away from him.

That explanation got carried away with itself, it probably isn't very good. I'm not even the guy you're talking to.

>>1757647

Wow, I didn't even realize I put 'intensive purposes', my apologies. I used to say it that way all the time, I'm still getting over it.

Yeah, but I'm not understanding the person I'm talking to. It's like he's trying to tell me there's no such thing as motion because everything is in motion with relation to everything else, and that if I say something is moving, it's not.

If the ship can't travel at 0.9999c, how does an ordinary space shuttle travel?

>>1757538
>So then if nothing happens to the ship at 0.9999c, why can't it reach >1c?

Let's say from the earth frame the ship is going 0.9999c. Let's say the ship is not currently accelerating, there is a reference frame, call it frame B, comoving with the ship, in which the ship has velocity zero.

Let's say the ship fires its 2nd stage rockets now. After the burn, the ship is now moving at .5c in frame B. So how fast is the ship now moving in earth frame? You add the velocities thus: (a+b)/(1+ab/c^2). So that works out that the velocity in earth reference is now 0.999966666c.

>>1757683

OOOOOOOOOOOOOH. -Now- it makes sense, thanks. :D

I fuckin' love math.

>>1757009
You still move at 99.999% of the speed of light.

You running is about : 0.0000001 of the speed of light.

Next?

This thread confirms once again that Josef is the only one who here who understands these things.

We just have high school smart asses who think they have it all figured out and then fail to answer simple stuff about SPECIAL RELATIVITY!

>>1757706

you run pretty damn fast bro

>>1757712
>doesn't see the plethora of correct answers
>sucks some tripfag's dick

>>1757715
I'm a nigra. I has made for running.

the speed of light in a constant regardless of how fast you are going

Learn2Maxwell

>>1757696
np

>>1757773 Learn2Maxwell
wat

>>1757808
http://en.wikipedia.org/wiki/James_Clerk_Maxwell

>>1757808
Maxwell's equations are what established the fact that the speed of light must be constant in all reference frames, given that the laws of physics apply equally in all reference frames.

serious redshift

>>1757046
End of story. Velocity does not simply add.

ITT: Lots of folks who don't understand relativity. You don't gain mass as you accelerate. Your relativistic mass increases, but your mass remains constant. Fuck.

>>1758238
>understands consequences, but not causes
your ____ mass is constant. That's what mass is. Your inertia/momentum can change, but not the mass.