pg01202

That's like saying an orbit isn't a method of circumnavigating the globe, rather a result. A CTC is a path through spacetime just as much as a geosynchronous orbit. In other words, travelling through spacetime to a previous lightcone is the technique used to achieve the curve, the result of which is arriving at that earlier time.

That's my point. You seem to be stuck on talking about one method of time travel which doesn't require it, so from your perspective it's not a necessary problem, but I wasn't talking about CTCs since they're not the only method of time travel allowed by general relativity. Seriously, this is a thread about time travel. At the moment it is science fantasy because no method is even close to being physically plausible, so how about getting off your high horse and allowing other perspectives to join in the completely theoretical conversation?

Well then feel free to give it a go. How does GR describe the relative motions of an object that occupies the same space a different times?

No. Given that no-one has managed to incorporate QFT into general relativity (as I said in my last post), it's a bit pointless to discuss the macroscopic effects since no-one has any idea what form they will take. Once you try to incorporate quantum mechanics into practical applications it entirely depends on what theory you're basing your ideas on. Beyond the scope of SR and GR, the approaches to time travel remain entirely hypothetical because they're still based on hypothetical physics. So the ideas that I'm kicking around are, like yours, simply based on the hypothetical interpretations that I find most convincing.

You're going off one interpretation of relativity, one that current particle physics renders impossible to actually achieve. So I'd be careful with that, your analysis is perfectly valid but not necessarily true. If we knew how to describe conservation in time travel accurately this thread wouldn't exist.

Care to elaborate? Bearing in mind that I'm talking about conservation of information, not the ability to time travel. Edit: Thought I'd give an example. If we're standing in a park and I throw a pebble at you (apologies) and then travel 1 minute back in time when you're not standing in the same place and throw that same pebble in the same way, relativity cannot explain our relative motions.

It's not even a paradox in the monouniverse. Killing your grandfather (preventing your grandparents from meeting, let's not be bloodythirsty) will only affect linear cause and effect. Since reverse time travel requires you to have a different frame of reference from the time you came from, you break any cause and effect locally. So all you end up doing is orphaning yourself. Again, and not a reflection on previous posts, people make the mistake of thinking physical laws have some kind of physical manifestation rather than simply being a description of the limits of what the universe is capable of on its own. Time travel is not explained very well in any theory of relativity because they all require linearity. They can't explain two frames of references that are not in sight of one another (e.g. both on Earth but one in 2015 and the other in 1860).

What would be the physical law that requires this? Depending on your mode of relativistic effects, this either violates conservation of energy or is rendered meaningless by Lorentz covariance, since the local effects in a single point of general relativity aren't directly related to the global effects of special relativity. As I was saying above, it's very unlikely that general relativity would apply beyond a single point in spacetime (which I think you are alluding to), so what you do in the past would simply cut you off from the time you came from. Linear (general relativistic) time would need to obey the laws of conservation, so going forward from the point you changed would maintain the information that you altered. Information from the time you originally travelled from wouldn't disappear, you simply wouldn't have access to it.

I think there's a lot of anthropocentrism that prevents us from analysing time travel properly. We see it all the time with laws of nature, seen as immovable and implacable, but remember that they apply to closed systems. When you leave your linear time you leave the closed system and the laws don't have to remain consistent. Physical laws only describe what the universe has been capable of doing on its own. If you find a way to force interaction in ways that the universe has not been able to do on its own then you need new laws to describe what you're doing.

The only way I can see that reverse time travel would be possible is if time exists as a physical dimension, with information stored as energy. Even then, are you really going back in time or just reconstructing past events? What would you be comparing it to? From our perspective the changes made by time travellers would seem to be the natural chain of events.

Was there ever an answer for this? I've got a contract to test the M-38 UGS but there's no 'Run Test' button in the right-click menu.

Oh that's cool. So it's just a limitation of the game in not being able to display fractions on the UI.

I seem to have encountered an issue with the largest xenon container. If you stack two of them they drain at the same time, instead of the top one first, essentially making the second container useless.

I give all the experimental craft designs to Jebediah. He's survived this long, so I figure he's either lucky enough to make my dumb ship designs not blow up or he's due a fiery death.

Does anyone know how the atmospheric drag in 1.0 will affect orbit altitudes? I presume being under 70k will then be completely pointless, but will it slowly taper off after that or just be a hard cutoff point.