Sci Fi TV science or fiction?

Gerinski wrote: Dean wrote: Thanks, that was really constructive. I would just perhaps argue that, travelling at precisely the speed of light and looking back at where you come from, you would still see a still picture rather than just black nothingness. You would see black nothingness if you exceeded the speed of light by any fraction. But you are welcome to argue that, I'm not 100% sure.

Because the Lorentz factor is an inverse square law it also show why light-speed is an absolute limit. As you approach lightspeed the Lorentz factor increases until at light speed it is infinite, [the 1-(v/c)² term becomes zero], so the relative mass becomes infinite and thus the energy required to accelerate the ship to that speed also becomes infinite. Beyond light-speed the 1-(v/c)² term becomes negative, leading to a square root of a negative number (ie it is an imaginary number).

Gerinski wrote: Dean wrote: One phenomenon of space travel we've not broached yet is time dilation due to relative velocity Indeed. I should have been more careful and say that the trip would last 90 years, Earth or Sirius time. This would actually add to the fast-forward motion appearance I mentioned, since in my example of travelling a 0.1 c, the ship passengers would see 99 years of visual progress unfold in front of them during 89 ½ years of their time, and in your example travelling at 0.9 c they would see 99 years of progress happening during 39 ¼ years of their ship time.

Nearly.  I made an error in the 0.9c example.

Dean wrote: I should stress at this point that the 99 year compression (or 19 year compression) is an illusion due to the fact that an observer on Earth sees light from Sirius that was emitted 9 years earlier and as you travel towards Sirius the light you see is emitted sooner, when you are 1 lightyear closer the light is only 8 years old. [Similarily when you arrive at Sirius and look back to Earth, the light you see is 9 years old, it left Earth after you did]. You cannot profit from this compression.

Finnforest wrote: Stargate gate travel. I understand the idea between gate addresses and stable wormholes between them, even though bringing that to fruition is probably a few decades away yet.  ;)     What I don't fully grasp is the process by which the bodies are transported.  Disassembling and reassembling all of our particles on either side of a gate....how exactly does that work ?  I tried to find video of Carter or Jackson explaining that process but could not.  Is it similar to Star Trek "beaming"?

Edited by Dean - July 27 2013 at 11:51

To guage some idea of the scale of the problem of converting a human to energy and back again we would need to do this on an atomic level for each atom in the body.

I believe that Stargate gates are supposed to be some sort of wormhole. Wormholes are only a theoretical and extremely speculative possibility which, although do not strictly speaking violate the known laws of physics, require stretching the known theory to its very limits. And even if the theoretical principle is allowed, it seems close to impossible that we could ever achieve that sort of technology for any practical-size object.


Edited by Gerinski - July 27 2013 at 12:36

Dean wrote: Gerinski wrote: Dean wrote: Thanks, that was really constructive. I would just perhaps argue that, travelling at precisely the speed of light and looking back at where you come from, you would still see a still picture rather than just black nothingness. You would see black nothingness if you exceeded the speed of light by any fraction. But you are welcome to argue that, I'm not 100% sure. No, you would see nothing. The photons of EM radiation would be travelling at exactly the same speed as you are so they would never reach your eyes.   /edit: You can never see a still image - that is impossible. Once the photons hit your retina to form an image they are "spent" - our persistence of vision will maintain that image for 1/25th of a second and then it to will be gone. There will be no more photons arriving because they cannot travel faster than light.   Gerinski wrote: Regarding what we might "see" ahead of us, I get your points and yet I'm not sure of what a practical interpretation might be (regardless of the fact that we know that we can never achieve the speed of light in practice). I understand that we can not receive a photon before it has been emitted, in the hypothetical case of travelling at c towards the light source we would receive the photon just at the same time it was emitted. There is no practical interpretation over what I have stated - So no. You will see it after it has been emitted even if that "after" is septillionth of a second after, it will still be after, it can never be just at the same time.     Gerinski wrote: But if we agree that as we travel faster and faster we will see the events in front of us unfolding quicker and quicker, what is the limit when we approach light speed? what does it mean "watching the events happening in front you extremely fast but still not before they happened"? I assume it means seeing events simply as they truly happen, without any time delay due to the distance they are being observed from, so actually they would end up not looking fast-forward at all but at the same speed we perceive them now, just without any delay. But since we said that events would appear to happen quicker and quicker the faster we travel, I still have some doubts as to what might that mean in practice. Things would just appear to happen without any delay at all. Would that have any practically appearance effect? How would events shift from appearing to happen fast-forward (with increasingly smaller delay) to appearing to happen at normal speed (without any delay)? You are making the mistake of speeding up the light relative to the source not the observer - it is the observer that is moving relative to the emitted light from the source, relative to the source the light is unchanged.   So, there is always a distance between event and observer even if the observer is moving so the light still has to cross that distance. That takes a finite time so you will never see the event as it truly happened. At faster than light speeds you will be travelling that fast but the light coming towards you will still be travelling at the speed of light. If you are 1 light year from Sirius and travelling at 2 the light from Sirius will have taken a year to reach you, if you are travelling at a septillion times faster than light and are 1 light year from Sirius the light from Sirius will still have taken a year to reach you.   Secondly the scenario you described (of taking 90 years to cover the 9 lightyears to Sirius at 0.1) was a snapshot at t=0 (99 years compressed into 90). At half the distance you are 45 years away and see the light emitted 4.5 years in the past so you have compressed 49.5 years into 45; at three quaters of the way there you have 22.5 years left to travel and are seeing events on Sirius that happened 2.25 years ago so you will have compressed 74.25 years into 67.5... When you are one day away from Sirius you will be seeing events 2.4 hours in the past. So the closer you get to Sirius the events you are seeing are nearer to the present until the moment you arrive at your destination and you see things in realtime. No matter how fast you get there, you can only arrive at realtime, you can never overtake it.   Hope that's clearer.

I just want to mention that it is equally impossible to become invisible. Or rather, it is possible but with a serious "but": Anyone who is invisible automatically becomes blind.

As to speed of light: It can be argued that everything moves at the speed of light, on,ly in four dimensions, the fourth being what we notice at time. The Lorentz transformations make immediate sense when one thinks of them as the projection of four-dimensional movement into three-dimensional space. What's more: This view can also explain the duality of wave and corpuscle; you just have to think of a different concept of corpuscle. Instead of "mass bends time-space" you have to think of "mass IS bent time-space". We don't get the fluctuation of these waves though because as we move through that fourth dimension we lways stay at the peak of the wave, therefore it appears to be steady.

Anti-matter is just out of phase by 180°; thus wave peak and wave hollow extinct each other.

This model very nicely explains why nothing that has a mass can ever reach the speed of light in our three dimensions, because no matter how you increase thhe spedd in our three spatial dimensions there will always be a rest of speed along the fourth axis time. The relativistic corrective SQRT(1- v"/c") , or as I prefer to write it (SQRT((c"-v")/c") actually is the sinus of the angle the wave has with the time axis (any mathematician worth his salt should immediately spot the similarity of that corrective and the Pythagorean theorem with c being the hypotenuse and v one of the cathetii of a rectangular triangle).

This may all sound strange at first, but calculate it through. It works!


Edited by BaldFriede - July 27 2013 at 12:45

Yay! We have our own Kari Byron aboard here on SF Mythbusters  

Finnforest wrote: Assuming we had elaborate/sensitive enough technology for the steps of the process, is there something else about our bodies and the electrical/chemical components of our brain that would make reassembly with memories/personality impossible?