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  • #31
    Originally posted by M21Sniper
    ... The escape velocity for an object at the event horizon is C. Hence, if x-rays are escaping, they have an escape velocity greater than C.
    The emissions don't actually come from beyond the event horizons. They are caused by stellar matter infalling, and the high velocity of these particles, and high pressures at and near the event horizon, cause the collisions responsible for the emissions. Since nothing is actually escaping from beyond the event horizon, there is no need for superluminal velocities.
    "We will go through our federal budget – page by page, line by line – eliminating those programs we don’t need, and insisting that those we do operate in a sensible cost-effective way." -President Barack Obama 11/25/2008

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    • #32
      Assuming black holes exist in any form other than a math problem. :)
      No man is free until all men are free - John Hossack
      I agree completely with this Administration’s goal of a regime change in Iraq-John Kerry
      even if that enforcement is mostly at the hands of the United States, a right we retain even if the Security Council fails to act-John Kerry
      He may even miscalculate and slide these weapons off to terrorist groups to invite them to be a surrogate to use them against the United States. It’s the miscalculation that poses the greatest threat-John Kerry

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      • #33
        Originally posted by Confed999
        Assuming black holes exist in any form other than a math problem. :)
        Black holes are pretty well-established. Cygnus X-1, for instance, matches all the theoretical predictions of what black holes look like.

        -dale

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        • #34
          Originally posted by dalem
          Black holes are pretty well-established.
          Until someone sees one, they're just math. It could be something completely different, with similar characteristics. Faith is required to believe in black holes, until they are studied up close and personal.

          On a serious note, if everything has an equal and opposite, what are the black holes' equal and opposite?
          No man is free until all men are free - John Hossack
          I agree completely with this Administration’s goal of a regime change in Iraq-John Kerry
          even if that enforcement is mostly at the hands of the United States, a right we retain even if the Security Council fails to act-John Kerry
          He may even miscalculate and slide these weapons off to terrorist groups to invite them to be a surrogate to use them against the United States. It’s the miscalculation that poses the greatest threat-John Kerry

          Comment


          • #35
            Originally posted by M21Sniper
            "Going back in time is not possible because it requires traveling faster than the speed of light, which is physically impossible."

            Actually, that's not true.

            Gamma emmisions from the core of blackholes are ejected at greater than the speed of light.
            Einstein based the assumption that the speed limit (for everythign with a mass) in the universe is lightspeed. Up to now I am not aware to any proven observation that this is not ture.

            If this oberservation would have held up / will withstand further observation I think it is time for a new Nobel price in physics.

            Regarding the topic time travel. I think Stephen Hawkings expressed it well:

            If it would be possible we would be swamped with tourists from the future. Since this isn´t the case....

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            • #36
              Originally posted by M21Sniper
              The black hole faster than light emmisions are the only reason we can detect them to begin with.

              It's the X-Ray emmisions ejected from the event horizon that we are able to detect. The escape velocity for an object at the event horizon is C. Hence, if x-rays are escaping, they have an escape velocity greater than C.

              Pretty simple stuff.

              When matter "falls" into a black hole it heats up emmits radiation.

              This has nothing nothing to do with matter escaping a black hole or needing a velocity grater than C.

              What passes after something falls into a black hole is up to speculation since we have up to now no mathematical modell to describe what happens inside a black hole.

              As per definition we cannot observe directly a black hole. Basically it is a solution of the "Einsteinische Relativtätstherie". When a star dies with more (I think round about 5.7 the mass of our sun ) there is no force known to prevent the ever ongoing collapse when a star is burned out. Thus creating a singularity in space.

              We can predict the effects that such an object in space should provoke. The nice thing is that the predictions what we can observe came mostly true and up for now. we don´t have a better modell to explain these effects though the theory of black holes is quite well established.


              It is believed today that nearly all galaxies have a massive black hole in the center. Wen it is starve as in our galaxy it is hard to observe. In other active galaxcies we can observe massive emmisons of mass and radiation for example as jet streams. Simply big quantities of mass are falling towards the black hole heats up and is "blown away".

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              • #37
                Originally posted by deadkenny
                Well, there are subatomic particles that travel 'backward' in time, so it is possible in some sense.
                The QM equations are bi-directional wrt time, but there are no actual observations of particles going "backwards" in time- it's just a mathematical model. To "prove" this, we would have to set up the detectors today, observe the particles that have no source, and then run the experiment tomorrow to create the interactions we observed today...
                "We will go through our federal budget – page by page, line by line – eliminating those programs we don’t need, and insisting that those we do operate in a sensible cost-effective way." -President Barack Obama 11/25/2008

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                • #38
                  Originally posted by Confed999
                  Until someone sees one, they're just math. It could be something completely different, with similar characteristics. Faith is required to believe in black holes, until they are studied up close and personal.
                  My point is that we are seeing them. Some high-energy X-ray bursters and the like (and I mean HIGH energy) fit the profile for particle impact and destruction on the accretion ring of something with a very high gravitational potential and in a very small volume.

                  So I would place them somewhere way beyond "just math".


                  On a serious note, if everything has an equal and opposite, what are the black holes' equal and opposite?
                  You're confusing Newton's Third Law of Motion with something else. There is no cosmological "requirement" that objects have "opposites".

                  -dale

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                  • #39
                    Travelling back in time might be possible. But it would only move you back in time.

                    That is I get in my time machine, key in 22/11/63 and press go. I then arrive in 22/11/63. Unfortunately i am still in the same place i was in the universe, which is millions of kilometres away from Dallas at the time. Even if i press go on my time machine sitting in Dealey plaza tomorrow (15/5/05) Dealey Plaza isn't in the same place in the universe it was 42 years ago. since the Earth has moved a long way following the Sun, which has moved a long way itself. My time machine would be floating in space hundreds of billions of miles away from Dealey Plaza . At this point i wish i had upgraded my time machine to the "star drive" option so that i can get about in space - although i would have to use a relativistic speed to get to where Dealey Plaza was in '63. Even if i could adjust my course to allow for the time dilation to get there.

                    Which might be why we can't see travellers from the future. Because whilst they might be able to move in time. They still have the problem of moving through space which would then take time ....

                    I think.

                    Of course the other answer is to simply look for any blue Police 'phone box that has just appeared and ask the nice man inside to take you somewhen fun. It seems much easier in the Tardis :)
                    at

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                    • #40
                      Originally posted by dalem
                      My point is that we are seeing them. Some high-energy X-ray bursters and the like (and I mean HIGH energy) fit the profile for particle impact and destruction on the accretion ring of something with a very high gravitational potential and in a very small volume.

                      So I would place them somewhere way beyond "just math".
                      But none of that proves the existance of a "black hole". That "something" could be very different in nature than the description of a "black hole". There is something there, exactly what is a question that can currently be only answered with "I believe it is a" at the begining.
                      Originally posted by dalem
                      You're confusing Newton's Third Law of Motion with something else. There is no cosmological "requirement" that objects have "opposites".
                      Bad explanation, sorry, I'll try again. Assuming there are black holes of the basic nature described by popular science, is there a point where the energy/matter absorbed by a black hole comes to be released? A point where the fabric of space rips instead of folding, and explodes with the same violence in which it was compressed?
                      No man is free until all men are free - John Hossack
                      I agree completely with this Administration’s goal of a regime change in Iraq-John Kerry
                      even if that enforcement is mostly at the hands of the United States, a right we retain even if the Security Council fails to act-John Kerry
                      He may even miscalculate and slide these weapons off to terrorist groups to invite them to be a surrogate to use them against the United States. It’s the miscalculation that poses the greatest threat-John Kerry

                      Comment


                      • #41
                        I wonder, what would life be like if time traveling (forward and backward) is made possible? What would our society be like once we have discovered all of Earth's misteries? When there is nothing left to find out, research, or doubt, and everyone knows the answers to everything, because we are able to look beyond and before the present?
                        Remember, the enemy gate is down- Andrew ¨Ender¨ Wiggin

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                        • #42
                          Originally posted by Jonathan Locke
                          I wonder, what would life be like if time traveling (forward and backward) is made possible? What would our society be like once we have discovered all of Earth's misteries? When there is nothing left to find out, research, or doubt, and everyone knows the answers to everything, because we are able to look beyond and before the present?
                          All that would be left is to create a universe with different natural laws than our own, to fully become God. Then the reseach and exploration could begin anew. ;)
                          No man is free until all men are free - John Hossack
                          I agree completely with this Administration’s goal of a regime change in Iraq-John Kerry
                          even if that enforcement is mostly at the hands of the United States, a right we retain even if the Security Council fails to act-John Kerry
                          He may even miscalculate and slide these weapons off to terrorist groups to invite them to be a surrogate to use them against the United States. It’s the miscalculation that poses the greatest threat-John Kerry

                          Comment


                          • #43
                            Originally posted by Confed999
                            But none of that proves the existance of a "black hole". That "something" could be very different in nature than the description of a "black hole". There is something there, exactly what is a question that can currently be only answered with "I believe it is a" at the begining.
                            Then you technically have to start every sentence dealing with astronomical phenomena with "I believe it is a". Even for the Sun.

                            You're basically swinging on the semantic underpinning if the concepts. You are correct in that no one has put a black hole under close observation. I am correct in that everything about what we think black holes are fits into where we think black holes are.

                            Bad explanation, sorry, I'll try again. Assuming there are black holes of the basic nature described by popular science, is there a point where the energy/matter absorbed by a black hole comes to be released? A point where the fabric of space rips instead of folding, and explodes with the same violence in which it was compressed?
                            Mmm, I think Hoyle first theorized so-called "white holes" that ejected matter into the universe. I think that cosmological concept has been pretty much left in the dust. I also believe Hawking has developed a theory of black hole "evaporation" due to matter-antimatter particle-pair creation events at the event horizon of a black hole that seems to hold up mathematically.

                            I might be misremembering those two though.

                            -dale

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                            • #44
                              Originally posted by Confed999
                              All that would be left is to create a universe with different natural laws than our own, to fully become God. Then the reseach and exploration could begin anew. ;)

                              Doesn't work like that. Because we would see into the future and watch ourselves creating said universe, then we would look farther into the future to see what would happen with the universe. So, either way we would know the answers and problems before we actually lived the situations.
                              Remember, the enemy gate is down- Andrew ¨Ender¨ Wiggin

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                              • #45
                                Originally posted by dalem
                                Then you technically have to start every sentence dealing with astronomical phenomena with "I believe it is a". Even for the Sun.
                                Not just astronomical phenomena. ;)
                                Originally posted by dalem
                                Mmm, I think Hoyle first theorized so-called "white holes" that ejected matter into the universe. I think that cosmological concept has been pretty much left in the dust. I also believe Hawking has developed a theory of black hole "evaporation" due to matter-antimatter particle-pair creation events at the event horizon of a black hole that seems to hold up mathematically.
                                You know I remember the white hole thing, but that seems pretty far fetched, even for an anything can happen person like me. Evaporation is more likely, but even then wouldn't there come a point where the mass of the black hole wouldn't be enough to sustain the fold in space? I've allways loved the exploration of space, but I was a biology person, and know little about it. :)
                                No man is free until all men are free - John Hossack
                                I agree completely with this Administration’s goal of a regime change in Iraq-John Kerry
                                even if that enforcement is mostly at the hands of the United States, a right we retain even if the Security Council fails to act-John Kerry
                                He may even miscalculate and slide these weapons off to terrorist groups to invite them to be a surrogate to use them against the United States. It’s the miscalculation that poses the greatest threat-John Kerry

                                Comment

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