Thread: Science Stuff...Time travel and stuff.

Originally posted by docthory
i have some thing to state on the fact of speed of light and stuff ok here goes

according to some law and physics if i am standing in the bed of a pickup truck and it is going 50 miles or kilometers per hour and i throw a ball in the direction that we are going in the truck at 50 mph or kph then to some one standing on the side of the road would see the ball going 100 mph or kph right

and if i am standing in the same truck going the same speed and i throw the ball in the oposite direction at 50 mph or kph then to the bystander the ball would just sit there or fall (i cant remember what one it was)


so you may ask your selfs what dose this have to do with the speed of light and this is what it has to do with it.

ok i am back in the truck and it is dark out side and im on a highway going about 70 mph or kph and i turn on my head lights !!! how fast are the light wave going according to the info above the light beam should be going at the speed of light plus 70 mph or kph or does it????

so is it posible to go faster than the speed of light

There is something fundamentally wrong with this, but I just can't think what. It's 3 in the morning...

No, the light wouldn't be going faster. That's one of the puzzling effects of the laws of physics. There was an experiment (I'm a little tired right now too, so I can't remember who did it) to test this: The tested the speed of light both going the same direction as Earth's orbit, and going the opposite direction. Since Earth is spinning relatively fast, it should be clear to see a change that large in light speed, but when the experiment was performed, both measurements came out to be the same number. No matter how fast you move, light always moves at light speed relative to you.

Originally posted by docthory
i have some thing to state on the fact of speed of light and stuff ok here goes

according to some law and physics if i am standing in the bed of a pickup truck and it is going 50 miles or kilometers per hour and i throw a ball in the direction that we are going in the truck at 50 mph or kph then to some one standing on the side of the road would see the ball going 100 mph or kph right

and if i am standing in the same truck going the same speed and i throw the ball in the oposite direction at 50 mph or kph then to the bystander the ball would just sit there or fall (i cant remember what one it was)


so you may ask your selfs what dose this have to do with the speed of light and this is what it has to do with it.

ok i am back in the truck and it is dark out side and im on a highway going about 70 mph or kph and i turn on my head lights !!! how fast are the light wave going according to the info above the light beam should be going at the speed of light plus 70 mph or kph or does it????

so is it posible to go faster than the speed of light

Nope. What you just described is essentially the thought experiment that lead Einstein to develop his general theory of relativity. The fact that an observer on the ground would not measure light going faster than 2.998E8 m/s is what leads to the interesting (aka weird) relativistic effects such as time dilation and length contraction (This gives a visual of some of those thought experiments). General relativity states that there is no prefered inertial referene frame-- all are just as good and the laws of physics must therefore be the same in each. This includes the measured speed of light. As long as two observers in relative motion are in inertial reference frames, neither observer can say whether s/he is moving and the other person is still or the other person is moving and s/he is still. In fact, such distinctions cease to make sense in relativity. Although the earth is a non-inertial reference frame (due to the presense of gravity), the analogous situation using your truck example would be to say that the driver of the truck has just as much right to say that he is sitting still in his truck while the earth spins beneath him as the observer on the side of the road has to say that he is standing still and the truck is zooming past. (Of course, this isn't true because of what I just explained about earth being a non-inertial reference fram, but it helpls you get the idea).

I think the experiment that Tsen is talking about is the Michelson-Morley experiment. Here is a flash version of the experiment. Check it out.

Yeah! I thought it was the Michealson-Morley experiment...but somewhere in the back of my mind somebody was telling me that the Michealson-Morley experiment was something to do with bacteria. Ptsh...stupid mind.
O_o ...I should probably get some sleep now. I've had 5 hours in 3 days...

to do something like traveling through time you would need energy on the scale of that released in the big bang. if you want to know more about this pick up a copy of hyperspace by micheal kaku

Actually you just need to move.

Depending on what you mean by traveling through time you don't have to do anything at all, just wait.

time travel cant be done


You cant rewind reality
you cant speed up reality


but if it is possible then it would be more likely to be able to go back the forward.

Originally posted by eyeofgames
time travel cant be done

Incorrect.

Its quite simple actually, all you need is a Flux Capacitor. Of course you will also need to generate 1.21 gigawatts of electricity, but you could easily do that will a plutonium powered nuclear reactor or lightning (since plutonium is hard to come by). Get up to 88 mph in a sweet-ass car and you'll be time traveling in 'no time'.

its never been done then. If it was wed see people form the future all the time .

Originally posted by eyeofgames
its never been done then. If it was wed see people form the future all the time .

Well, travelling back in time is much trickier than travelling forward.

ps. Back to the Future is the best movie ever.

Its quite simple actually, all you need is a Flux Capacitor.[/b]

I'm so freakin' tired of hearing that term! Do you even have the foggiest to what it means?

Dipwads.

Now, 1.2 G-Watts really isn't impossible. It's a lot, but a large nuclear reactor could probably handle it. If it was quite that simple to have time travel on a large scale, it would be done already.

On the other hand, movement is traveling in time. Not a percievable amount, but it is traveling in time nonetheless. If you were to move at a few thousand miles per hour for several years, the difference could be measured in seconds, perhaps less. Really, it only affects things moving near the speed of light to a significant degree (as far as we know)

Originally posted by Tsen
I'm so freakin' tired of hearing that term! Do you even have the foggiest to what it means?

Dipwads.

Now, 1.2 G-Watts really isn't impossible. It's a lot, but a large nuclear reactor could probably handle it. If it was quite that simple to have time travel on a large scale, it would be done already.

Everyone knows that the flux capacitor is what makes time travel possible by temporarily storing the flow of time. No one said generating 1.21 gigawatts is impossible, in fact I'd bet by 2015 with the use of fusion we could generate it with garbage!

Going back in time would create an endless loop

1800-----------1900--------------2000
| <--------------------=------------- { }
| |---------------------------------> { ETC }
| <--------------------=------------- { }
|-------------------------------------------->

A person would go to 1850 say, then time would go back to 2000 eventually. Where they'd go right back to 1850. And it continues.

Travelling BACKWARDS in time is something to be speculated about. It's not a proven theory. Personally, I'm highly skeptic here. And for heaven's sake, DROP THE FRIGGIN' FLUX CAPACITOR JUNK BEFORE I HURT THINGS! "Temporarily store time" my ASS! And what do you suppose we'll catch it with? A mason jar? ARGH! Now if you can logically explain how to create such a device, I might actually listen. But I can tell ya', it isn't lookin' like a smart option to be betting anything on. There's no specific theory available for stowing time a way in a box or anything, so you'll be working from scratch, and provided you succeed, you'll be the only one in a field where MANY people much smarter than yourself have failed miserably. Hell, I'd nominate you for the Nobel prize myself if you manage to get a quarter of the way to the solution.

And 10 years from now is a pretty damn optimistic outlook for the availability of cold fusion.

Dude, you're nuts. Watch Back To The Future.

Originally posted by Joseph_Stalin
Yes, but there is another factor, which is perception. For example, say I am accelerated to the speed of light, and I stop accelerating 200 years later. Although to everyone else I have traveled 200 years, for me, it has been almost instantaneous.

This is a very good point that needs to be addressed, I think. What needs to be taken into consideration is that space contracts as well as time. When you move at high speeds with respect to your surroundings, the surroundings will look flattened in the direction you are travelling. So if you were speeding towards a sphere it would look as if you were coming down on top of a pancake.

At a high enough speed, if you are seen by others as traveling for 200 years then you will only experience 2 years while you travel. But you will see the universe moving at the same speed as they see you moving. The reason your trip seems quicker to you is that while the outsider sees the overall distance travelled as being say, 100 light years, you will see the distance as being only one light year. Note that relativity works the same for the person that is "moving" and the person that it "still"; its just a matter of perspective (The outsider will see your spaceship as flattened, but that does not matter here )



Also, time travel is possible. A time machine was designed by Michio Kaku, but it would take the energy of six suns to make it work (just like Leonardo DaVinci designed a helicopter but couldn't get an engine strong enough to power it). There have been other designs for time machines, too, but they all take up way too much energy.

The reason that people have not come in from the future is that a time machine can only take you back to a time after the time machine was created. The only way they could get to our planet in this time is if they found an older, natural time machine created by the big bang or a blackhole or something crazy like that (maybe a cosmic string ). But there apparently (thankfully? hopefully?) isn't anything like that in our remote neighborhood.

Anyway, time travel may not be practical anyway because the human brain may not be able to comprehend this kind of stuff. Maybe the way it uses thermodynamics to work with information would be disrupted , and then our brains would just react as if the time-travelled stimulus had not occured , and then we would just basically go insane and die ...

But maybe it wouldn't be that bad; I really have no idea !

Ok, when and if it was possible you travel at the speed of light your are not necessarily going back in time, time just moves slower because you are accelerating through space-time so rapidly that time cannot catch up. You need to read more and try to understand more, no offense.

Yes, you would be, in effect, going back in time. You would be travelling to an area before it could influence you, in essence travelling back in time.

Basically, an event happening NOW, twenty light years away, will not influence me in the slightest for AT LEAST twenty years. So, even though that event happened now, for all points and purposes it won't happen for another twenty years, because I'd have no way of knowing it happened, feeling the influence of it happening (barring Einstein's 'Spooky Action at a Distance'), or have any other way of inferring that something happened. Simply put: The event twenty light years away doesn't happen HERE for another twenty years. If you could travel beyond lightspeed and reach that area twenty light years away in only five years, you would, in essence, be travelling fifteen years back in time and discovering something that otherwise wouldn't have happened for fifteen more years.

I suppose it isn't time travel as most people imagine it (Getting in some fancy box and zapping themselves twenty years back instantaneously without ever travelling in the more common three dimensions), but it IS, literally, travelling back in time.

Originally posted by Tsen
Basically, an event happening NOW, twenty light years away, will not influence me in the slightest for AT LEAST twenty years. So, even though that event happened now, for all points and purposes it won't happen for another twenty years, because I'd have no way of knowing it happened, feeling the influence of it happening (barring Einstein's 'Spooky Action at a Distance'), or have any other way of inferring that something happened. Simply put: The event twenty light years away doesn't happen HERE for another twenty years. If you could travel beyond lightspeed and reach that area twenty light years away in only five years, you would, in essence, be travelling fifteen years back in time and discovering something that otherwise wouldn't have happened for fifteen more years.

Right, and if you came back to your original position going the same speed, you would be in the same place as where you started, only in the past.

The speed of light is the cosmic limit. NOTHING goes faster than the speed of light.

You can NOT reach the speed of light. The time travel would be caused if you were to go 99.99% the speed of light. If you were on the ship and began to run across, you would break the speed of light, correct?

Wrong, you can't run fast enough as it slows down time to prevent you from breaking the limit.


Stephen Hawking on the Science Channel FTW.

Isn't the reason for not being able to reach the speed limit that no matter how fast you go, light travels at the same speed relative to you?

I thought it was more to do with the fact that it is constant, rather than an actual limit.

But... I really don't actually know.

Well yes, but I don't know if that's why it's the cosmic limit.


Time travel back is impossible. First, we would have to enlarge a wormhole to the past, which can be done.
But wormholes are not very far back in time at all. If you were to enlarge a wormhole, as there are wormholes all around us, it would go back maybe a minute tops. It would get to the point where you enlarged the wormhole and the feedback would become infinitely great, destroying it.

If you were to travel back an hour, you would add more mass than was previously there, and mass cannot be created or destroyed. Well, it can be created through travelling back, but then in an hour you would travel back again, and this makes the universe instantly have infinite matter, destroying it.

Forward, on the other hand.. If you were to be traveling near the speed of light, on say, a super train. After accelerating fast enough (would take about six years at full throttle of a rocket ship/rocket train to reach 99.99% light speed.) time would slow so that if you were to run up the train you couldn't break it, as you couldn't run fast enough. We have no idea what happens then, but time protects that from happening. Maybe for a reason, maybe not, but either way it does. Going this exact speed, one week on the train for you, and once you leave you would be 100 years into the future. Therefore, it is time travel, in a basic sense. People outside would see you on the train for 100 years, but you only for a week.