How does someone measure that a particle has been sent to the past?
You build a mechanism now that sends a particle to the future upon receipt of a particle from the future, then later on you send a particle back in time to that mechanism.
Are we getting close to time travel?
21–30 of 39 posts
Re: Are we getting close to time travel?
#22Why do people bother researching into time travel? Even if it's possible, it's potentially a massively dangerous act. Nobody should have the power to alter events outside of the present in any way, shape or form. Period.
Similar reasoning is sometimes used against researching and publishing information on security vulnerabilities in software.
Yet in practice it's better to publish that openly, lest the blackhats abuse the vulnerabilities for their purposes unhindered.
Re: Are we getting close to time travel?
#23This is just silly. If time travel were possible, it would have been invented already in the future and our world would be a very different place.
How do we know the world isn't already a different place and the future just decided not to tell us about it?
People don't work that way.
Re: Are we getting close to time travel?
#24The faster you travel, the faster time goes relative to things stationary to you it could be possible that some particles are spinning off at some multiple of the speed of light, and is aging much faster than we are, and having spent millions of years existing in the space next to the collision, evaporates or flips into another place by chance.
Re: Are we getting close to time travel?
#25Earlier quoted context omitted.
I can't imagine a greater human achievement than time travel.
The good thing about time travel is that it would make FTL space travel possible as well.
In the general case, time travel is only good for making terrible, terrible science fiction plots.
However, FTL is well justified. Even with various limitations (e.g. you can only use it for instant communications, or only robots can travel), it'd be an utterly fantastic leap for mankind.
Re: Are we getting close to time travel?
#26Maybe in this context it would be useful to reflect about time . Our life is a continuous concatenating of present moments. And every present moment is new. But where do they come from? Nobody knows. I see time as a continuous gift from Someone outside of our physical Universe. No other explanation is logically possible, because any explanation would come from inside our Universe -- but fresh new present moments can'…
I'm not sure if your post is meant to be read as philosophical/theological or as your actual interpretation of the way time exists in our universe.
If it's the latter, you might find sections of RobotRollCall's first comment in this reddit discussion enlightening: http://www.reddit.com/r/askscience/comments/fjwkh/why_exactl...
If it's the former, well, I guess you're probably right. Nobody knows. At least, nobody thinking about it in a purely philosophical/theological context.
Re: Are we getting close to time travel?
#27>"Because time travel is limited to these special particles, it is not possible for a man to travel back in time and murder one of his parents before he himself is born, for example. However, if scientists could control the production of Higgs singlets, they might be able to send messages to the past or future," This is absurd. If you can send messages back in time, then someone can build a robot that can accept mess…
Well, to be fair, the ability to send messages to the past really only becomes useful once such messages are receivable. For the messages to be receivable, we must know the properties of the medium that the messages are to be sent on.
Basically, this limits the very earliest that such backwards going messages can be received to around now-ish.[1]
As a consequence it may not be a paradox anymore, since there will be no point at which we can operate without a suspicion of future interference, thereby reducing the paradox effect, and in fact encouraging it by divining the outcomes of our actions. Of course this divining rapidly loses power anyway, as multiple messages are sent conflicting with one another - it gets messy quick. It gets messier quicker if you choose to go with a "many worlds" interpretation of the universe. Further, there are questions regarding observation: does observing a message from the future cement that future into being, possibly incurring an absurd chain of events but not causing any paradox (the 12 monkeys thing)?
What I am really driving at here is this: Your paradox claims are amusingly simplistic, the real deal here is that we just don't know enough to say.
[1] I am ignoring two big possibilities: 1. that this has been known for some time by, say, evil wall street bankers with secret labs (and their ilk -- governments, supervillians and such). 2. That there aren't aliens at some point in the very distant past whom we get messages to, and convince to do our bidding, who show up at various key stages of history an change everything. This may or may not have happened, depending on what you believe from the history channel (ancient aliens) and Stargate.
Re: Are we getting close to time travel?
#28An "instance in time" is simply the state of all energy at any one moment. I say "all energy" because our reality is comprised of 1) energy in many different forms and 2) space - the container of the energy.
To travel back in time would be to reverse the course of all energy - from the perspective of a segment of the energy. Given the total amount of energy in our reality - that's not very likely.
Re: Are we getting close to time travel?
#29Earlier quoted context omitted.
How do we know the world isn't already a different place and the future just decided not to tell us about it?
People don't work that way.
Re: Are we getting close to time travel?
#30Earlier quoted context omitted.
I can't imagine a greater human achievement than time travel.
The good thing about time travel is that it would make FTL space travel possible as well.
The implications for computing might be interesting as well... (Charlie Stross mentions this in some of his stories).