New model confirms that time travel is possible + it resolves the 'grandfather paradox'

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And here are the highlights:

Researchers speculate that time travel can occur within a kind of feedback loop where backwards movement is possible, but only in a way that is "complementary" to the present.

In other words, you can pop back in time and have a look around, but you cannot do anything that will alter the present you left behind.

You go back to kill your father, but you'd arrive after he'd left the room, you wouldn't find him, or you'd change your mind...

Here's one of my favorites:

This means that you cannot be killed when you go back in time, nor can you kill or destroy anything! That's just perfect!!

Go back in time and be able to observe, only... no ability to interact with anyone either... it should be kinda like ghosts... we go back in time and observe and be like ghosts in the sense that we cannot interact and change anything that has already happened but only observe!

Imagine the possibilities of history classes of the future... maybe there are already a lot of ghosts watching us right now... the future students studying history!!

Actually, there's nothing that would prevent you from being killed on your journey to the past. You just couldn't kill your past self. Your present future is unknown, so you may not survive your trip to the past.

... and be like ghosts in the sense that we cannot interact and change anything that has already happened but only observe!

I could be wrong, but isn't it realistically impossible to observe a reaction without changing the outcome in some way? This was the idea behind Schrödinger's cat.

Just as it's impossible to get the exact temperature of a cup of hot tea - the calorimeter has to absorb some heat to work - it would be impossible for the light to be absorbed into the students' eyes. Assuming time is infinite, the number of time-travelling students occupying our time approaches a fraction of infinity (still infinity); at which point all the light would have been absorbed. Since that hasn't happened, the students must be akin to deaf, blind, comatose, senseless mutes.

Ergo - students of the distant future will be no different than students of today. QED and get off my lawn!

\t\t\t***

What can I add? I'm glad such a theory exists, and now that time travel is backed up, I can go on with my stories ;-)

The thing is that I don't understand what's the big deal about this article? When I thought about time travel and its impact on the future or present [think Asimov and 'The end of eternity'], I also considered the option that things evolve in a different way - i.e. no matter what you do, you end up with the same present/future anyway. Something like "de ce te temi, de-aceea si dai" ;-)

A long time ago my dad told me that I'll have problems with a ladder or a staircase. Now, what the heck am I supposed to do with that information? If I avoid ladders, then
(A)one day I'm going to die because I didn't use a ladder when it was my only way to escape OR
(B)one day I'm gonna die because I didn't pay attention to the prediction and DID use a ladder

Either way, the ladder is involved, and all the events are a consequence of my own decisions. If I choose to influence my future (not use the ladder) then I die; If I choose not to influence the future (use the ladder, discarding dad's advice) - I'm still dead.

The prediction was right: "I'll have problems with a ladder."... But just like any other prediction, it fails to be useful. It is exact, but not useful. (Remember the joke about Holmes, Watson and their location - "in the balloon") ;-)

If my example isn't really good, then consider the situation in Star Wars ep. III - the guy tries to save his wife because a prediction tells that she will die; end he ends up to be her killer. Got it?

You know what I think?
NEVER make predictions ;-)

All these gipsy-ladies and fortune tellers are not only crooks, but they're also those who alter your future by altering your mind.
Instead of letting you live your life and act as your mind tells you, a prediction complicates things... Not only complicates, but it actually tends to become true even if it is bogus. Here's an example:

An old woman predicted that you'll never get married. So, what does that mean, and how will it influence your future?
(A) you screw the prediction and live in peace, getting married eventually
(B) you screw the prediction and live in peace, you don't get married in the end
(C) you pay attention to the prediction and you get married
(D) you pay attention to the prediction and you don't get married

If it's B or D, then who's the one to blame? Yourself? or the fortune teller? go figure... %-)

It could be the fortune-teller, you know.. And not because she (yes, I believe there are no males doing this.. but who knows?) actually saw something, but because she had to predict something.
It could be you, because her words upset you, and someting changed inside your psyche (thoughts like "nobody needs me", "I will never make it"...)... you become a non-optimist... And you don't get married because you did it to yourself. But THIS 'doing it to yourself' is a consequence of what she did to you!

Now, what did the highlight say about the cup of tea? You cannot measure its temperature without affecting the temperature.

In other words, if you try to predict the future, you alter it.

Holy cow! Did I write that?!?! Sounds very weird...
But hey, you've read the arguments... So now you can do the math yourself.

Other reading material:
Novikov's principle

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