Way off topic: Seeing back in time.

Discussion in 'General Discussion' started by Blackjack, Sep 10, 2006.


  1. Blackjack

    Blackjack Monkey+++

    I posted this on another forum I belong to as well, I'm really curious about the answer. Since I'm a security guard, nobody at work is smart enough to even understand the question let alone give me an answer and I know there are some science geniuses lurking around in here.



    When we see the light from a distant star, say 100 light years away (arbitrary number for demo purposes), we are seeing that star as it was 100 years ago. It may have died out 99 years ago.

    Now, in theory only of course, if I could instantly transport 150 light years away from earth and had a telescope big enough, and discounting things like interference and degradation, could I watch the civil war unfolding back on earth? For that matter could I transport millions of light years ahead and watch a tyrannosaurus feeding? Who shot JFK? What spawned Rosie O'Donell? Did emperor Xenu actually fly Tom Cruise here in a spaceplane?


    My initial reaction is no.... but consider something:

    When I look out the window at my car, I'm seeing my car as it was 1xxxxxth of a millisecond ago, not as it presently is, right? Why... because it takes time for light from it to reach my eyes, no light, no image. So my vision doesn't reach out and capture an image, images only exist within the light reflected off of them.

    I'm probably way off base here, but I would really like someone to explain it to me....... slowly if need be :)
     
  2. RightHand

    RightHand Pioneer in a New World Moderator Founding Member

    I admit that when I was in college, physics coarses were among my favorite and successful classes but I had trouble wrapping my brain around the relativity of light and time.

    That said, my instinct tells me the answer would be NO since the propogation of light is independent of its reception. If I instantly travelled the 150 light years you mentioned, the destination would be 150 yrs in the future, not 150 yrs in the past.

    I hope someone else will add to this and, as Blackjack said, slowly....
     
  3. Blackjack

    Blackjack Monkey+++

    "If I instantly travelled the 150 light years you mentioned, the destination would be 150 yrs in the future, not 150 yrs in the past."

    But I'd be looking back at the earth, which the light from has been travelling for 150 years........ where's Hawkings when you need him? Or at least Kirk.
     
  4. ghrit

    ghrit Old, mean, and nasty Administrator Founding Member

    RH is right on with the statement of the speed of light being independent of it's reception, but it is also independent of it's propagation. Stating your question as you did eliminates the time travel question, and permits "same time" frame of reference. Stated the way you asked allows you to go look into the past, but you would have to use the same path to return, thus arriving back here at the same time you left (and in the process lose the view of the past that you had while gone.) Or so it seems to me.
     
  5. RightHand

    RightHand Pioneer in a New World Moderator Founding Member

    I may be starting to see the light, so to speak. I guess the "instantly" reference makes sense but my understanding is still cloudy.
     
  6. ghrit

    ghrit Old, mean, and nasty Administrator Founding Member

    Don't count on me for clarity in the area of E=mc^2. (Pretty good with classic Newtonian physics, tho' --):D
     
  7. RightHand

    RightHand Pioneer in a New World Moderator Founding Member

    Same with me ghrit. Newtonian physics made sense to me. I got hooked in my first coarse and designed all sorts of hydraulic devices starting with a tractor complete with schematics. I never thought I would actually use the knowledge but years later, I worked in the weighing industry eventually moving into sales. I'd have to spec out hopper systems to handle throughput. The gate systems were hydraulically operated and would be custom designed to meet the requirements of the product, draft size and bushels or pounds per hour. It satisfied the latent engineer in me.
     
  8. ghostrider

    ghostrider Resident Poltergeist Founding Member

    Y'all are actually doing pretty good on the Einsteinian theory, also. Adding the fourth dimension of time means two points in space could co-exist at some point in time.
     
  9. RightHand

    RightHand Pioneer in a New World Moderator Founding Member

    Makes me want to go back and take another class just to try, once again, to fully grasp the concepts. Maybe I'll try to plan a class for the spring semester.
     
  10. monkeyman

    monkeyman Monkey+++ Moderator Emeritus Founding Member

    Yup, I would say that Ghrit nailed it. As long as you could 'instantaniously' travel to a point X light years from earth then you would be able (if you had good enouph optics to see more or even the detail of the contenents and oceans) what was happening on earth that number of light years ago since the light from that time would just then be reaching that point and the light is what allows us to see anything. So you would be able to see what happened at that point in time.

    Where it really starts to mess with the grey matter is when you start thinking of the deeperimplications of Einsteins theories, time travel, etc and how they would effect this since you are traveling or teleporting there instantly then you would be going at many times the speed of light and theory implies that when moveing beyond the speed of light then not only perception of events but the relevence of time on the person/object traveling is changed and that there can be an actual traveling back in time and/or that a person traveling at that speed for say 1 min then returning to the point they left would return to find that years or decades had passed to others.

    The basics pertaining to the question asked I have a fair grasp of but once it gets into more of the abstract and deeper levels of it I get a little fuzzy. If I had any idea how to get ahold of him I did have a class mate though who as I understand skipped several grades and by his late teens was employed in a think tank working on some of the stuff Einstein left unfinished.
     
  11. RightHand

    RightHand Pioneer in a New World Moderator Founding Member

    With full admission that I struggle with the concept, it would still seem that if I was instantly transported to that distant destination, the light being produced NOW (which I'm not yet perceiving) is actually 150 light years in the earth's future so that is what I would see, the future, not the past. To see the past, would one not have to "become the light?"
     
  12. Seacowboys

    Seacowboys Senior Member Founding Member

    Ah Grasshoopah...you are on the road to wisdo.foosed
     
  13. Seacowboys

    Seacowboys Senior Member Founding Member

    If you will recall, sound waves are basically energy and there-by are never destroyed, just dispersed and obsorbed. Bell Labs has been working for a number of years, to be able to isolate and extract sound waves from objects,for instance, rocks. In theory, they should be able to recall sounds from the past, like maybe an actual recording of Lincoln doing his Gettysburg Address. I first heard of these experiments in 1978 and do not know what, if any success, they may have experienced.
     
  14. Blackjack

    Blackjack Monkey+++

    Cool, sounds like I'm on the right track


    Quick Sherman, into the Wayback Machine!
     
  15. ghrit

    ghrit Old, mean, and nasty Administrator Founding Member

    Yes, the light coming from there will be seen in earth's future. Think frame of reference. If you jump to the distant object, light from earth takes the same time to get there as light from there takes to get here. Thus, looking at earth from there, you are seeing the past. Looking at there, from there, you see the present as it is there, not the future. Could you remember what you saw there, you would know the future of there on your return to earth, not vice versa. (I think.) Said slightly differently, while there you are experiencing what we will see in the future. Assuming you arrived there in some sort of civilization, you could make a mint forecasting what they would see if they trained their telescopes on earth.foosed (I think.)

    I really do not think it is possible to do time travel, since where ever you are is the present, and I believe the process has to be reversible, excepting for time distortion assuming a physical transport limited by Einstein's equations. That said, assuming travel at or near the speed of light, time is distorted. And I do not remember how it is distorted, nor how to develop the equations to show it.

    But I can develop the equations that show your toe will hurt if you drop a hammer on it. Newtonian at it's finest, and all in the NOW time frame.[no]
     
  16. Seacowboys

    Seacowboys Senior Member Founding Member

    What if time really isn't relative to motion but rather it just appears that way within the parameters that we can preceive? What if light doesn't actually have speed but rather actually begins and ends at the same time between objects? Maybe then exisance could be a state of light everywhere and only shadows exist and a flashlight, for example, basically only removes them (the shadows) from the immediate picture with all of the strenght of it's battery power. If this were true, then all of the angels could dance on the point of a needle and global warming will not matter to anyone except for those of us that can't afford air-conditioning. It clearly come down to wether or not darkness actually exists or is it just a defense mechanism that we created to justify blindness?
    (I knew those chemicals would come back to haunt me...)
     
  17. ghrit

    ghrit Old, mean, and nasty Administrator Founding Member

    Maybe still? After all, Timothy said they are another path to enlightenment, grasshoppah.:D
     
  18. RightHand

    RightHand Pioneer in a New World Moderator Founding Member

    I'm afraid the younguns are going to be lost by the references!
     
  19. ghrit

    ghrit Old, mean, and nasty Administrator Founding Member

    hehehe. Betcha not. Still amazes me what the young'uns aquire by osmosis that we had to try out for ourselves. 'Course, I mixed two references in that one just for the confusion factor.:D
     
  20. RightHand

    RightHand Pioneer in a New World Moderator Founding Member

    Makes you wonder what they say that is totally lost on us!!!
     
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