speed of light?

Trippy discussions of moral issues, conspiracy theories, the paranormal and other otherworldly phenomenon.

Moderator: Dracofrost

speed of light?

Postby TerraFrost » Sat Sep 20, 2003 3:35 am

as objects approach the speed of light, time slows down. so, if some object travels at the speed of light for two seconds, fifteen seconds might have passed for another object that wasn't traveling at the speed of light... this begs the question... at what speed is the first object traveling, from the perspective of the second object, that isn't traveling at the speed of light?

for simplicities sake, assuming the speed of light was 1/2 meters per second, the first object would have traveled 1 meter in 2 seconds. however, from the perspective of the second object, the first object would have traveled 1 meter in 15 seconds, giving us a speed of 1/15 meters per second. i'm guessing that if a third object were traveling at 1/15 meters per second, it would appear, from the perspective of the first object, to be traveling at some speed slower than that, but that's just a guess.

of course, there is another way to determine the speed at which something is moving at relative to another objects speed, but that result doesn't seem to account for time dilation (time speeding up / slowing down). if an object was moving at 1/2 meters per second, that is precisily how fast it would appear to be moving to the other object, if it wasn't moving.

so, anyways, from this, it seems to me that there is probably a limit how fast we will see something moving at - one that depends on both relative speed and the relative passage of time. i don't think this was talked about in my physics class, but maybe giga's will have some different topics, or something :)
TerraFrost
Legendary Guard
 
Posts: 12357
Joined: Wed Dec 04, 2002 6:37 am

Postby Gigafrost » Sat Sep 20, 2003 3:48 am

Maybe my course will talk about it. In any case, it's something that sort of baffles me. I mean, if something goes the speed of light and it moves forward in time faster, wouldn't it appear to move faster than the speed of light?

Hmmm...
User avatar
Gigafrost
Frost Weapon
Frost Weapon
 
Posts: 4900
Joined: Wed Dec 04, 2002 5:09 pm
Location: Here

Postby TerraFrost » Sat Sep 20, 2003 3:58 am

it actually moves foward in time slower than objects that aren't traveling as fast. atleast from the other objects perspective.

from it's own perspective, time is traveling faster for the objects that are traveling slower than it.

so, pretty much... time slows down the faster you go, sorta.

which also makes me wonder... is there some speed at which time would have slowed down enough to make it appear as if you aren't moving at all, even though you really might well be?
TerraFrost
Legendary Guard
 
Posts: 12357
Joined: Wed Dec 04, 2002 6:37 am

Postby Dracofrost » Sat Sep 20, 2003 4:45 am

Well, the way I understand relativity, for you subjectively the closer you approach the speed of light the slow time is, but the thing is, you never can actually reach the speed of light. You can accelerate forever and just get closer and closer, but pretty much the way time slows down from your point of view, you just keep going faster and faster. So you could travel across the entire length of the galaxy and it could seem just a second to you...

So subjectively, one can appear to travel faster than light, it's just that that's an illusion of time dilation. Er, I think that's how it works... but I've never taken college physics classes...
User avatar
Dracofrost
Frost Drake
Frost Drake
 
Posts: 6683
Joined: Thu Dec 05, 2002 4:55 am
Location: Crossed into the Blue

Postby Exalted Ugu » Sat Sep 20, 2003 5:24 am

And since anything travelling at the speed of light is incapable of observing, or being observed by anything else, what actually happens at that point is really irrelevant.

-ugu
Exalted Ugu
Townfolk
 
Posts: 102
Joined: Sun Sep 07, 2003 11:18 pm

Postby TerraFrost » Sat Sep 20, 2003 6:11 am

time dialation doesn't just occur at the speed of light - it occurs as you approach it... as an example of this, stephan hawkings, in a brief history of the universe, suggested that people on planes will have a few extra seconds added to their life, becaues planes travel so much faster than normal modes of transportation. of course, people on the space shuttle will live for even longer periods of time, and so on and so forth... i expect it actually grows exponentially...

in any case, i found the answer. time dialation isn't the only thing that happens as you approach the speed of light... length contracts, as well.

the relationship is apparently something like this...

(distance from x to y from obj. 2's perspective) / (time from x to y from obj. 2's perspective) == (distance from x to y from obj 1's perspective) / (time from x to y from obj. 1's perspective)

also, draco's post reminded me of an interesting theory about black holes that i read somewhere... to quote from a post on slashdot.org that described it...

In my college astronomy class, the professor told us that Russian astrophysicists call black holes "collapsars." The reason being that (according to prevailing theory, I guess) once inside the black hole event horizon, you would look down and see the surface of the former star collapsing - but it never quite makes it to the "singularity" stage.

It's just perpetually collapsing.
TerraFrost
Legendary Guard
 
Posts: 12357
Joined: Wed Dec 04, 2002 6:37 am

Postby lorien1 » Sat Sep 20, 2003 10:48 am

Image"Hope Is All We Have.Do You Have Something Worth Living For"
User avatar
lorien1
Recruit
 
Posts: 305
Joined: Mon Jul 14, 2003 1:11 pm
Location: Scotland

Postby Dracofrost » Sat Sep 20, 2003 4:11 pm

Well, yes, time dilation occurs at speeds less than light speed, but really, it's just so incredibly small of an effect until you really get into serious percentages of lightspeed. And it's not like it's a linear progression either; time isn't slowed down by 1 percent when you're traveling at one percent of light speed. It's more of an exponential thing, that just grows infinitely before reaching absolutly no time passing at all at lightspeed, but that can't be reached anyways.

What I find particularly intresting, though, is time dilation caused by gravitational effects. I'm still not quite sure how this works...
User avatar
Dracofrost
Frost Drake
Frost Drake
 
Posts: 6683
Joined: Thu Dec 05, 2002 4:55 am
Location: Crossed into the Blue

Postby TerraFrost » Sat Sep 20, 2003 4:48 pm

The Speed Of Light


unfortunatly, that site doesn't mention time dialation or length contraction, that occur as you approach the speed of light... but it does look a good site, all the same :)

Well, yes, time dilation occurs at speeds less than light speed, but really, it's just so incredibly small of an effect until you really get into serious percentages of lightspeed. And it's not like it's a linear progression either; time isn't slowed down by 1 percent when you're traveling at one percent of light speed. It's more of an exponential thing, that just grows infinitely before reaching absolutly no time passing at all at lightspeed, but that can't be reached anyways.


yeah... i'd kinda expect that, as per my understanding of it...

and i've never heard about any time dialation caused by gravitational effects... can you elaborate?
TerraFrost
Legendary Guard
 
Posts: 12357
Joined: Wed Dec 04, 2002 6:37 am

Postby Dracofrost » Sat Sep 20, 2003 4:57 pm

Well, I've heard that intense gravitational fields can have effects similar to relatavistic speeds; so that, say, inside of an event horizon time really really slows down (thus perhaps the theory of collapsars and them never being able to fully collapse, perhaps?)

And I've also heard of experiments to verify this in the form of two atomic clocks, one at the top of a water tower, the other at the bottom. And because of the vanishingly small difference in gravity caused by the difference in distance from the center of the earth, the one on top got like a microsecond fast in a month or something. Whoop dee do...

But, I don't remember where I heard of these things, so I don't know where one would look to confirm these things...
User avatar
Dracofrost
Frost Drake
Frost Drake
 
Posts: 6683
Joined: Thu Dec 05, 2002 4:55 am
Location: Crossed into the Blue

Postby taenadar » Sat Sep 20, 2003 5:01 pm

great... now im probably too dumb to understand this :D

Image

"If you drink to forget, please pay before you drink"
User avatar
taenadar
Elite Guard
 
Posts: 1154
Joined: Fri Mar 28, 2003 8:14 pm

Postby Gigafrost » Sat Sep 20, 2003 5:28 pm

The theory that gravity bends time has, more or less, been tested and confirmed. I've heard about that atomic clock theory as well.

I read about a theory concerning how the universe was formed. It's interesting in that it is somebody trying to have the universe created specifically like the bible said, except he's trying to use physics to prove it. I suppose the weirdest concept in it is the idea of a "white hole"...which is sort of like a black hole, except that time slows down closer to the center...

Anyways, the idea was to...

1) Have the earth created as the center of the universe...
2) Have the earth be only 6 days old when the heavens (IE stars) were created...

Unfortunately, there are a couple of logical problems I see with that theory. Now by that theory, the universe is *still* billions of years old, and even worse relative to the universe, the earth itself would also be billions of years old (although it would have aged only 6 days). In addition, it has matter appearing out of nowhere, solidifying to form the earth and also spreading out into the universe, creating the galaxies we observe now. Also, if the earth was slowed down while the rest of the solar system and\or galaxy wasn't then the earth wouldn't move as fast, would it? Or would the forces on it be magnified so greatly that when the white hole disappeared the earth would be sent flying into space at an abnormally high speed?
User avatar
Gigafrost
Frost Weapon
Frost Weapon
 
Posts: 4900
Joined: Wed Dec 04, 2002 5:09 pm
Location: Here

Postby TerraFrost » Sat Sep 20, 2003 8:09 pm

Well, I've heard that intense gravitational fields can have effects similar to relatavistic speeds; so that, say, inside of an event horizon time really really slows down (thus perhaps the theory of collapsars and them never being able to fully collapse, perhaps?)


i actually had assumed that collapsers were just perpetually collapsing in on themselves, although you're conclusion doesn't seem to be all that unreasonable, either :)

And I've also heard of experiments to verify this in the form of two atomic clocks, one at the top of a water tower, the other at the bottom. And because of the vanishingly small difference in gravity caused by the difference in distance from the center of the earth, the one on top got like a microsecond fast in a month or something. Whoop dee do...


i recall hearing about that, actually, heh. although that said, i think speed could also explain this phenoman. consider a tire. additionally, assume you have some random point x labled on the axel, and some random point y on the edge of the tire. if the axel turns ten degrees, the length of the line connecting x's old location and x's new location will be, say 1 inch. in contrast, the length of the line connecting y's old location and y's new location will be, say, 10 inches. so, point y has moved faster than point x. similarily, while there may be less gravity at the top of a skyscaper than there is at the bottom, the top of the skyscaper should also sorta revolve around the earth faster than the bottom of it should, in which case, speed could once again be an explanation.
TerraFrost
Legendary Guard
 
Posts: 12357
Joined: Wed Dec 04, 2002 6:37 am

Postby Dracofrost » Sun Sep 21, 2003 1:34 am

So then to properly test that theory we just need to perform the same experiment at one of the poles... You know of any good water towers in antarctica?
User avatar
Dracofrost
Frost Drake
Frost Drake
 
Posts: 6683
Joined: Thu Dec 05, 2002 4:55 am
Location: Crossed into the Blue

Postby TerraFrost » Sun Sep 21, 2003 3:57 am

that's a good idea, actually, heh. :)

i would ask at the place i asked my previous question, but... bah. when some people encounter a question they can't answer, instead of simply not answering it, they attack you, for asking what they see as a stupid question. of course, to such people, science is just a religion. science is only different from religion when it can stand up to questions, but ah well... i suppose some people simply don't understand that which they claim to believe in, heh.
TerraFrost
Legendary Guard
 
Posts: 12357
Joined: Wed Dec 04, 2002 6:37 am

Next

Return to Twilight Zone

Who is online

Users browsing this forum: No registered users and 1 guest

cron