[jawns]

If I were a time-traveler from 2025 to 2013, and things were roughly as described, you can bet I would go straight to Reddit and tell, in lurid detail, the tale of this digital dystopia.

Not because I expect it to change the outcome. Time travel doesn't work like that.

No, I would do it because I would need to do it -- because in a sense, I had already done it. I would, in all likelihood, already be aware of having done it, because during the time leading up to my temporal voyage, I would have read the words time-traveling me had already written.

And I would be very glad to do it, whether or not I had a choice in the matter, because I would already know about the Bitcoin I would receive from amused Redditors for having done it.

I might have to return to the dystopian future, but I would return very rich. Probably rich enough to afford adequate security protection and to live out the rest of my days in luxury. It might not be the best outcome for the human race as a whole, but it would be a very good outcome for me.

[kumarvvr]

These sort of arguments seem to solidify the notion that time-travel is not possible in the current setup of the universe.

[baldfat]

Time traveling backwards is not possible. Time Traveling forward happens the faster you move. Satellites have to compensate for the fact that time is different the faster you go.

[cowmoo728]

I think it's "time traveling forwards happens slower the faster you move."

The easy explanation is that we're traveling in a 4 dimensional space at the speed of light, and any increase in speed in the 3 spatial dimensions must subtract from your speed in the orthogonal time dimension.

[dvdkhlng]

Maybe in an Orthogonal Universe [1,2], but not in ours :)

The way you state it, traveler's time would speed up (as the resting frame's time of journey would be decreased).

[1] http://www.gregegan.net/ORTHOGONAL/00/PM.html

[2] http://www.gregegan.net/ORTHOGONAL/02/Motion.html#LR

[baldfat]

If I jump on a ship and travel near light speed (Not possible yet) and then land on the same spot I would not have spent the same time as those on the earth.

Now at a tiny level anyone ever on an airplane also will have spent less time than those who never have flown.

[kumarvvr]

I have always wondered, when satellites have to have their clocks compensated, is it that they are experiencing time differently, but are still in present time?

To rephrase it, how does one know they are not in "now" but the past? apart from maybe measuring ages of their counterparts etc.

[QAPereo]

Travel back in time and travel faster than light are logically equivalent, and seem to be utterly impossible in our universe. “c” does seem to be the iron law, the speed of causality, but of course who knows? I don’t see a universe without causality having people in it though!

[yiyus]

Time-travel is absolutely possible, as long as it is always in the forward direction and at a (relatively) constant pace.

[zaarn]

Time Travel totally works in forwards.

In backwards it's probably more like winding up a tape; you can rewind all you want but the tape contents won't change.