A Brief History of Time

[Tyguy]

I was listening to this audio book and found it very interesting. For those of you who don't know what it is, its a book by Steven Hawking which basically tells you a little of everything regarding our Universe and our place. What I found the most interesting is how we theoretically know how to Time Travel, forward that is. The example they give is as follows....

Theres a rocket ship in a vacuum which is exactly 1 light second in height. At the top is a guy with a clock who send a light signal to another guy at the bottom every second. Now in a vacuum without gravity or acceleration, the light will take exactly 1 second to reach the guy at the bottom. Now pretend the rocket ship is accelerating to near the speed of light. The guy at the top sends a light signal, yet the guy at the bottom receives it in less that a second. Assuming they keep accelerating, the time between signals gets less and less.

Now imagine you are in an elevator in space. All of a sudden you start to go towards the floor. As the elevator accelerates, you feel more and more like your on earth. What is the main difference between acceleration and being in a gravity field, relative to the individual?

The point they are making is that gravity does the say thing to light as acceleration does, making the speed of light relative to the person, not a constant.

Anyway, I kinda just regurgitated that, but I think its pretty cool, thoughts?

 

[PRSC2H]

Thats too complicated I don't undestand.

 

[ZeeM]

Thats too complicated I don't undestand.

Go read cosmopolitan

 

[PRSC2H]

I dont know too much about science but I thought the speed of light is constant? E = m c square

 

[Tyguy]

thats Energy = Mass times the speed of light. Einsteins theory of relativity showed that the assumption of absolute time and distance was incorrect and that mass and energy are different only in form.

 

[PRSC2H]

So mass and energy are the "same" thing?

I don't understand thi part "Theres a rocket ship in a vacuum which is exactly 1 light year in height. At the top is a guy with a clock who send a light signal to another guy at the bottom every second. Now in a vacuum without gravity or acceleration, the light will take exactly 1 second to reach the guy at the bottom."

1 light year is the distance light will travel in year. shouldn't it take 1 year instead of 1 second?

 

[Tyguy]

So mass and energy are the "same" thing?

I don't understand thi part "Theres a rocket ship in a vacuum which is exactly 1 light year in height. At the top is a guy with a clock who send a light signal to another guy at the bottom every second. Now in a vacuum without gravity or acceleration, the light will take exactly 1 second to reach the guy at the bottom."

1 light year is the distance light will travel in year. shouldn't it take 1 year instead of 1 second?

yes, my mistake

 

[Polaris]

A Brief History of Time is one of my most favourite books. Also I have another Hawking's book - The Universe in a Nutshell, pretty good reading too (with more pictures).

 

[Deadline]

I was listening to this audio book and found it very interesting. For those of you who don't know what it is, its a book by Steven Hawking which basically tells you a little of everything regarding our Universe and our place. What I found the most interesting is how we theoretically know how to Time Travel, forward that is. The example they give is as follows....

Theres a rocket ship in a vacuum which is exactly 1 light second in height. At the top is a guy with a clock who send a light signal to another guy at the bottom every second. Now in a vacuum without gravity or acceleration, the light will take exactly 1 second to reach the guy at the bottom. Now pretend the rocket ship is accelerating to near the speed of light. The guy at the top sends a light signal, yet the guy at the bottom receives it in less that a second. Assuming they keep accelerating, the time between signals gets less and less.

Now imagine you are in an elevator in space. All of a sudden you start to go towards the floor. As the elevator accelerates, you feel more and more like your on earth. What is the main difference between acceleration and being in a gravity field, relative to the individual?

The point they are making is that gravity does the say thing to light as acceleration does, making the speed of light relative to the person, not a constant.

Anyway, I kinda just regurgitated that, but I think its pretty cool, thoughts?

Well I have a thought, one day while I was trying to hang my clock on my bathroom wall, I slipped while standing on my toilet and bumped my head. I came up with this.

Flux Capacitor > Hawkings Theory

 

[Tyguy]

Well I have a thought, one day while I was trying to hang my clock on my bathroom wall, I slipped while standing on my toilet and bumped my head. I came up with this.

Flux Capacitor > Hawkings Theory

Even Hawking doesn't understand that technology

 

[Dekstar]

Well we're travelling forward in time constantly. Oh look I just did it then, and again! And again!

 

[Stigmata]

There is no time. There are only permutations of the locations of atoms.

 

[hungryduck]

Well I have a thought, one day while I was trying to hang my clock on my bathroom wall, I slipped while standing on my toilet and bumped my head. I came up with this.

Flux Capacitor > Hawkings Theory

Agreed. You have the brightest mind of the 21st century!

 

[PRSC2H]

Is it possible to travel back and forth in time? (IN theory of course) I also herd it is possible to travel back in time only up to the point in which the time machine was built. Can someone explain this ??

 

[Cole]

You can't really time travel foward in time.

What you can do is decrease the time it takes to percieve the information of an event. However if an event hasn't happened yet, theres no way to percieve the information, therefor you can't see events that haven't happened, and therefor it isn't at all time travel.

You can't travel backwards in time either. What you can do is recieve old information(for example, when we see stars were often recieving what happens on those stars billions of years after they happened). The only way to travel backwards in time would be to reverse all the chemical reactions that are happening..however if you did that, you wont be going backwards in time because time is always going forward.

 

[nofx]

I read this the summer of tenth grade, goddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd.

 

[<RJMC>]

*me reads explanation*
.
.
.
.
.
*me grabs cosmo*

 

[TechnoHippyChic]

Have you seen Nova's The Elegant Universe? Good stuff along the same vein, but updated, with great animation and bits on M / Brane theory and such. This is a pretty amusing little page on time travel.

Edit:

Argh! Have to modify my avatar and sig again. Still think something like this would be cool...

 

[Anthraxxx]

Holy crap. It's THC...

 

[TechnoHippyChic]

Ever had DMT?

 

[63]

Anyone had a go at 'A Briefer History of Time'?

 

[CyberPitz]

*me reads explanation*
.
.
.
.
.
*me grabs cosmo*

That's exactly what I was thinking.

 

[TechnoHippyChic]

Aww, c'mon - I bet there's a necropedophysicist in there somewhere...

 

[_Z_Ryuken]

You can't really time travel foward in time.

What you can do is decrease the time it takes to percieve the information of an event. However if an event hasn't happened yet, theres no way to percieve the information, therefor you can't see events that haven't happened, and therefor it isn't at all time travel.

You can't travel backwards in time either. What you can do is recieve old information(for example, when we see stars were often recieving what happens on those stars billions of years after they happened). The only way to travel backwards in time would be to reverse all the chemical reactions that are happening..however if you did that, you wont be going backwards in time because time is always going forward.

^This is truth.^

 

[clarky003]

I always read American scientist, I also have read alot about particle physics and fringe science, 5D space time with string theory yadda yadda.

I've listened to some of Tom Beardens talks about experiments which are very interesting no matter what you think of him personally, and actually make sense in the light of particle physics and string theory especially. He gives some information on the history of how Clerk Maxwell's origional equations allowed for broken symmetry electromagnetic operations until Lorentz came along and arbitrarily discarded Maxwell's quanternion equations because they were too complex to calculate at the time, but he believes that's where scientists have lost the plot when it comes to practical unified field theories.

He gave one quite nice description of the realtionship between electromagnetisim and gravity, and that is to imagine a pressure cooker that contains all the potential energy in the universe, a large door in it is open spewing out pressure as EM radiation giving us our visible mass etc. Theres a smaller hole in the back of the cooker which is leaking pressure out elsewhere at a slower rate, this loss of pressure out the back is what we perceived as gravity.

The practical idea if you are talking about an atoms EM and gravitational properties is this.. Pressure release is normally in balance, and if you block EM pressure by covering the door or shutting it, it then has to go out the other way. That extra pressure out the other end, which is the gravity end would theoretically result in increased gravitational effect. In reality that would envolve 'blocking' EM decay from the nucleus to the outer electrons.

Vice versa, if you block the back pressure (gravity) you get an increase in EM decay from the nucleus, the theory is based on the nature of EM waves they appear to have a component that is 180 degrees out of phase with the direction of any EM wave, which means there is a reverse potential wave going back toward the emmitter at the same time there is the normal EM wave going out and away, they call it phase conjugation.

edit:

It's actually quite hard to describe :/ .

I'll use a couple of diagrams

what we normally see

phase conjugation phenomena

 

[TechnoHippyChic]

Holy crap. It's THC...

!

 

[Kula Meenur]

OMG. Brain is now crying. i hope u r happy.

 

[Deadline]

Theres a rocket ship in a vacuum which is exactly 1 light second in height. At the top is a guy with a clock who send a light signal to another guy at the bottom every second. Now in a vacuum without gravity or acceleration, the light will take exactly 1 second to reach the guy at the bottom. Now pretend the rocket ship is accelerating to near the speed of light. The guy at the top sends a light signal, yet the guy at the bottom receives it in less that a second. Assuming they keep accelerating, the time between signals gets less and less.

Wait so... Theres a rocket ship in a vacuum which is exactly 1 light second in height. Say "Mr. Guy at the top" shoots a laser beam in space, at the guy at the bottom of the rocket. If the rocket is going really fast, lets say almost the speed of light, and "Mr. Guy at the top" shoots "Mr. Guy at the Bottom", it would in turn, reach him in less than a second, tearing open space and time itself, transporting him to the exact moment in time where he was concieved, where him meeting his parents killed "Mr. Guy at the Bottom"s infant form, causing his mother to lose bladder control, which in turn disrupts the space time continueum which destroys the Universe as we know it?

Did I get that right?

 

[Solaris]

How does this imply time travel?

 

[_Z_Ryuken]

How does this imply time travel?

You have to first believe c the speed of light is constant, which it isn't.

If c is constant, the fact it takes less time to cover a certain distance would imply time has decreased, or the "speed" at which time "happens" increases.
Everything is perception anyhow, and time can only be percieved so if you want to believe this is time travel, by all means, believe it.

 

[Tyguy]

You have to first believe c the speed of light is constant, which it isn't.

If c is constant, the fact it takes less time to cover a certain distance would imply time has decreased, or the "speed" at which time "happens" increases.
Everything is perception anyhow, and time can only be percieved so if you want to believe this is time travel, by all means, believe it.

The speed of light is constant, what changed is the speed of acceleration of the ship. Light will always travel at 186,000 m/s

 

[clarky003]

The speed of light is constant, what changed is the speed of acceleration of the ship. Light will always travel at 186,000 m/s

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

Photons move at a speed less than c, unless they are travelling in vacuum. This leads to several important effects, such as dispersion (see also refractive index). The slow-down in condensed matter, such as gases, liquids and solids, can be considerable. The group velocity of light can be lowered to arbitrary speeds, though only for an arbitrarily slow (low bandwidth) signal (see Slow light).

In certain highly unusual circumstances, it is also possible to prepare experiments in which the group or phase velocity of light exceeds c. Since these velocities are mathematical constructs, these faster than light observations do not indicate any contradiction with causality or special relativity, as no information or energy travels faster than c.

 

[Tyguy]

thats a theoretical idea, nothings been proven

 

[clarky003]

Photons going faster than c havn't been proven, but it's well known that it varies below c as light enters the atmosphere depending on the different seasons, density of the air and temperature.

it naturally happens in small amounts, and you can artificially induce it further.

http://news.bbc.co.uk/1/hi/sci/tech/655518.stm