Results 1 to 6 of 6

Thread: New model 'permits time travel'

  1. #1
    Join Date
    Oct 2004
    Location
    CUCE
    Posts
    1,343
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default New model 'permits time travel'

    New model 'permits time travel'
    By Julianna Kettlewell
    BBC News science reporter

    If you went back in time and met your teenage parents, you could not split them up and prevent your birth - even if you wanted to, a new quantum model has stated.

    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.

    The concept of time-travel is laden with uncomfortable paradoxes


    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. The new model, which uses the laws of quantum mechanics, gets rid of the famous paradox surrounding time travel. Paradox explained Although the laws of physics seem to permit temporal gymnastics, the concept is laden with uncomfortable contradictions. The main headache stems from the idea that if you went back in time you could, theoretically, do something to change the present; and that possibility messes up the whole theory of time travel. Clearly, the present never is changed by mischievous time-travellers: people don't suddenly fade into the ether because a rerun of events has prevented their births - that much is obvious.
    Code:
    "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"    Professor Dan Greenberger, City University, New York
    So either time travel is not possible, or something is actually acting to prevent any backward movement from changing the present.

    For most of us, the former option might seem most likely, but Einstein's general theory of relativity leads some physicists to suspect the latter.

    According to Einstein, space-time can curve back on itself, theoretically allowing travellers to double back and meet younger versions of themselves.

    And now a team of physicists from the US and Austria says this situation can only be the case if there are physical constraints acting to protect the present from changes in the past.

    Weird laws

    The researchers say these constraints exist because of the weird laws of quantum mechanics even though, traditionally, they don't account for a backwards movement in time.

    Quantum behaviour is governed by probabilities. Before something has actually been observed, there are a number of possibilities regarding its state. But once its state has been measured those possibilities shrink to one - uncertainty is eliminated.

    So, if you know the present, you cannot change it. If, for example, you know your father is alive today, the laws of the quantum universe state that there is no possibility of him being killed in the past.

    It is as if, in some strange way, the present takes account of all the possible routes back into the past and, because your father is certainly alive, none of the routes back can possibly lead to his death.

    "Quantum mechanics distinguishes between something that might happen and something that did happen," Professor Dan Greenberger, of the City University of New York, US, told the BBC News website.

    "If we don't know your father is alive right now - if there is only a 90% chance that he is alive right now, then there is a chance that you can go back and kill him.

    "But if you know he is alive, there is no chance you can kill him."

    In other words, even if you take a trip back in time with the specific intention of killing your father, so long as you know he is happily sitting in his chair when you leave him in the present, you can be sure that something will prevent you from murdering him in the past. It is as if it has already happened.

    "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," said Professor Greenberger.

    "You wouldn't be able to kill him because the very fact that he is alive today is going to conspire against you so that you'll never end up taking that path leads you to killing him."

    Greenberger and colleague Karl Svozil introduce their quantum mechanical model of time travel on the ArXiv e-print service.


    surfujuci na net-u naletjeh na ovaj chlanak na BBC portalu...
    Shta mislite vi o ovome...
    izgleda mi nemoguce...(putovati kroz vrijeme) :smile: malo mi je i smijeshna sama pomisao na to...

  2. #2
    Join Date
    Jan 2004
    Location
    Toshin Bunar
    Posts
    1,027
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Smiju ti se shpijuni poslati iz buducnosti :joint:
    "Dobro veče." - Milka Canić, supervizor "Muzičke slagalice"

  3. #3
    Join Date
    Jan 2004
    Location
    Podgorica
    Posts
    11,590
    Thanks Thanks Given 
    561
    Thanks Thanks Received 
    3,088
    Thanked in
    1,621 Posts

    Default

    Ko je ono rekao - Masine teze od vazduha? To nece nikad moci da poleti

  4. #4
    Join Date
    Feb 2004
    Posts
    26,304
    Thanks Thanks Given 
    2,782
    Thanks Thanks Received 
    3,940
    Thanked in
    1,909 Posts

    Default

    Quote Originally Posted by SKOJ
    Ko je ono rekao - Masine teze od vazduha? To nece nikad moci da poleti
    To je bilo za bumbara cini mi se
    Loše stvari dolaze u paketu, za dobre stvari treba vremena.

  5. #5
    Join Date
    Jan 2004
    Posts
    36,821
    Thanks Thanks Given 
    89
    Thanks Thanks Received 
    3,289
    Thanked in
    1,832 Posts

    Default

    Quote Originally Posted by SKOJ
    Ko je ono rekao - Masine teze od vazduha? To nece nikad moci da poleti
    @Sofronije
    Tako se ne prave avioni, to nikad neće da poletiiiiiiii
    -> Forma za naručivanje online stvari <-

    Bugi Vugi tapši Raduj se!

  6. #6
    Join Date
    Feb 2004
    Posts
    46,242
    Thanks Thanks Given 
    2,753
    Thanks Thanks Received 
    2,624
    Thanked in
    1,269 Posts

    Default

    Kao student fizike mogu samo reci - bullshit

    Pisca ovog teksta je izgleda tata samo tako mlatio dok je bio mali
    She is only here to annoy herself!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. TeXtovi Pjesama
    By Insane in forum Muzika
    Replies: 136
    Last Post: 02-10-12, 14:44
  2. Najljepse ljubavne pjesme
    By rain_wind_storm in forum Ljubav
    Replies: 451
    Last Post: 13-07-05, 00:10

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •