Time travel.. if its possible why havent we seen it.

[BetaNumeric]

Someone went back in time and killed your apostrophes!

You and I have the same surname!

I suppose you could say Hawking is an armchair physicist. I was after-all quoting him on infinity. I'll make sure I pass on your comments.

I think without context the statement is a poor one, be it from Hawking or Bob the Builder.

Have you heard of renormalization? I assume you have as you appear to be much smarter in this subject than I, and that's not sarcasm. But don't flatter yourself too much as I also find your comments a touch patronising.

Just to summarise, when inifinites enter euqations they are a nuisance, and subsequently theorists come up with ways to deal with them. I've never liked the notion since how can an equation be effective when part of it has been born out of frustration to some degree or at best elimintates the annoyance which is infinity.

The manner in which renormalisation deals with infinities is a consistent one. It isn't infinity - infinity = 5, that is just pulling numbers out your backside, it first 'controls' the infinity.

Many of the infinities in scattering amplitudes come from the fact they include the term Gamma(-D/2) where D is the number of dimensions and Gamma is the Gamma function. If D=4 Gamma(-2) is infinite. However, if you consider D=4+x for small x then you get an expansion of the form Gamma(-D/2) = A/x + B + O(x). In the limit of x->0 the O(x) terms vanish. The A/x term blows up and thus needs to be removed by a counter term. This leaves B, which is the 'prediction'. The decomposition of the expression into the A and B is well defined, you can't fiddle it. It is what is known as a Laurent expansion, a generalisation of Taylor expansions. As such the B prediction is from the theory, not what something you put in by hand.

And I should clarify that the second half of my last post wasn't aimed at you, more a comment in general.

 

[ProjectVRD]

Nonsense. Singular values in things like scattering processes form a central component of quantum field theory. String theory predicts the dimensions of space-time using regularisations. Quantum field theory involves integrating over infinitely many degrees of freedom via a functional integral. Significant research is done into the behaviour of multidimensional 'black branes', where the singularity of a black hole is not a point but a region. Topological flop transitions examine how the structure of space-time behaves as part of it collapses into a singularity and then reexpands. Hawking-Penrose theorems pertain to the inevitability of singularities in general relativity. Quantum mechanics is formulated in an infinite dimensional Hilbert space.

Infinities, of many different types, arise in physics, both in classical physics and more recent theoretical physics. To say physicists don't like them is just naive.

It would seem that a lot of the 'armchair physicists' have come out to give their 2 cents on physics in this thread. Suddenly the hardest problems in physics are 'obvious'. If only some of you were academics, reshaping our understanding of the universe instead of wasting your obvious physics talents on a forum.

Rather than complaining about things such as your perception that physicists can't 'think outside the box' why don't you try doing actual physics? I can assure you you'll soon change your mind about the behaviour of professional physicists if you stopped whining about it on the side lines.

As Beta says here, a lot of physicists think out of the box, if not all of them. They must think out of the box to prove their normal in the box belief correct in the first place. Contradictory in words I know, but I have confidence in what it means lol...

 

[jmc007]

10 mins, should take no more than 1-2 to read that.

oh and lol at the article, wild theories and fantasies in abundance for some media attention

Not exactly oulandish lol, maybe you skipped the bit at the end speed reading.
Brian Cox, professor of particle physics at Manchester University, said: “His ideas are theoretically valid. What he is doing is playing around at the edge of our knowledge, which is a good thing.

“He is pointing out that we don’t yet have a quantum theory of mavity, so we haven’t yet proved rigorously that sending information into the past isn’t possible.

“However, if time travellers do break into the LHC control room and pull the plug out of the wall, then I’ll refer you to my article supporting Nielsen’s theory that I wrote in 2025.”

 

[garyfl]

i love my thread, some mature discussion and not the typical GD i know either

 

[skullman]

http://hosted.ap.org/dynamic/stories/E/EU_BREAKING_LIGHT_SPEED?SITE=AP&SECTION=HOME&TEMPLATE=DEFAULT

interesting

 

[Jimz]

Whos say that someone hasnt already travelled back but isnt allowed to make any changes to the future.

But it could happen at anytime really, tomorrow the news will be on and they have found a timetravel ship from the future, it just can happen from anytime now onwards

 

[kwerk]

Our ancestors HAVE seen it. Have you ever watched Ancient Aliens?

Not aliens... TIME TRAVELERS!

 

[Srengam]

Tim travel will never ever be possible,

if it was, people from the future would have come back to tell us.

 

[munz]

Tbh if they are smart enough to invent time travel, im sure they could "blend in" or have some sort of devices to help in this, magic wardrobe/surgery to alter evolutionary changes/ holograms/or something. Damn even invisiblity so they can see us but we cant see them.

The gloomy part is.. we never invented time travel because we as a race dont last that long.

 

[LabR@t]

Tbh if they are smart enough to invent time travel, im sure they could "blend in" or have some sort of devices to help in this, magic wardrobe/surgery to alter evolutionary changes/ holograms/or something. Damn even invisiblity so they can see us but we cant see them.

The gloomy part is.. we never invented time travel because we as a race dont last that long.

Aha

 

[RedDanDoc]

The only problem is that this theory would mean that for every action every single thing on this Universe does or is subjected to will have a its own Universe and its own timeline. Can you imagine how messed up the Multiverse would be with Time?

I'm guessing that Infinity is the key word here.

Oddly enough this theory technically destroyed the career of the Physicist that proposed it.

 

[Bhogal]

It is possible...if you travel to Adamstown, Austrailia from the UK, you will be going back in time!

 

[Blackhawk47]

Here it is. In the comments people metion you can see the top of the phone.

Also there is the Philidelphia Experiment, most people have heard of though I never heard this story before

Time to put this video to bed, the old woman is using something like this:
http://www.phisick.com/a7et82lutz.htm

I personally don't believe so much in time travel per say, but the research and studies into quantum physics really interest me...there is a really good documentary which was posted here before (was on iPlayer I think).

 

[eXor]

I'm from the future.

Lies.

I see no FutureHovis.

 

[Pottsey]

I agree with vonhelmet here. If we have the technology to invent time travel then we would have the technology to plot where the earth has already been at any point in the past.

Infact, I'm pretty sure it's already possible. Just look at the juno satellite mission. If that's possible now, I'm sure by the time time travel is invented we will be able to carry out the much more complex calculations needed (if we can't already).

I really don’t think you understand the sheer size of what we are talking about. More so as you seem to think we might be able to already and just because you can time travel is does not mean you can solve all the other problems with technology. It’s not just complex calculations we need updated faster than light sensors, faster than light travel. Map of the galaxy to see what mavity objects would affect Earths location. Map of galaxy’s that effect movement off our galaxy. EDIT: Not to mention you would need a map of all supernovas and other temporary objects that would effect the solar systems location.The Juno satellite mission is like trying to use a Stone Age cave drawing to navigate the world compared to what we need. Then once all that is done and once you somehow travail back in time you need to travel though deep space with FTL to get to Earth. All these problems make time travel vastly more complicated than most people realise. (This is assuming we are not talking about a machine linked though two points of time and you can only travel to the points that machine existed)

What if time travel proves to be real but faster than light travel is not. That alone would explain why we don’t get visitors from the future.

 

[Sharlaw]

TBH if you could move travel back and forward in time, would you really come here, now???

 

[Cosimo]

TBH if you could move travel back and forward in time, would you really come here, now???

Back to GD, yes.

 

[The Dread Pirate]

TBH if you could move travel back and forward in time, would you really come here, now???

No I'd go back to before OcUK was founded and become Spie!

 

[Ace Modder]

Right, this is my opinion.

We were led to believe that nothing can travel faster than the speed of light! However their are now claims that particles have been proven to travel faster than this.

In essense this means that if we travelled faster than the speed of light you could travel away from something and see something which happened previously. And if essense you are seeing something from the past, hence you could travel away from something faster than the speed of light and then watch as the light. For example if something happened yesterday on earth you could travel away from the earth for 1 day at twice the speed of light, then look at the light from the earth you would see what happened yesterday now. ie. Time travel.

However what you cannot do is travel faster than the speed of light to interact with the past. As it's already happened.

 

[The Dread Pirate]

Right, this is my opinion.

We were led to believe that nothing can travel faster than the speed of light! However their are now claims that particles have been proven to travel faster than this.

In essense this means that if we travelled faster than the speed of light you could travel away from something and see something which happened previously. And if essense you are seeing something from the past, hence you could travel away from something faster than the speed of light and then watch as the light. For example if something happened yesterday on earth you could travel away from the earth for 1 day at twice the speed of light, then look at the light from the earth you would see what happened yesterday now. ie. Time travel.

However what you cannot do is travel faster than the speed of light to interact with the past. As it's already happened.

What if we added a treadmill to the equation?