Continental Drift

fun website. Interesting for UK to see how it was above then below then above sea level many times.

I watched the last program of the 'Earth' series this evening and was rather disappointed. I don't tolerate Chris Packham for long anyway, but this program skipped over about 50 million interesting years to spend 15 minutes being santimonious about modern life at the end.
 
Back in a while.

The fact that the Earth, Solar System and the entire Milky Way Galaxy are hurtling through space may explain why time travellers have never come back to report their success!
 

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I haven’t left yet. I hadn’t charged the batteries in quite a while so I can’t try until tomorrow.

Galu: can you imagine returning, wondering where your planet went and coming to grips with your momentary lapse of reason?

Jeff, tonight is leftovers. Then we head to the mall as we don’t have A/C here. Hope you’re doing okay in the heat.
 
Well, in addition to creating a mechanism for time travel, a "relative spatiality compensator" must be fabricated. The earth rotates on its axis, the Earth undergoes precession, the Earth orbits the sun, the solar system "orbits" along one of the spiral arm of our Milky way galaxy...Calculating an exact place in space at any one time in the past or future would be immensely difficult...without this precision, one could easily "materialize" back in say the 1920s, but 330 feet up in the air...


----------------------------------------------------------------------------------------------------------------------------------------------------------------Rick...
 
Well, in addition to creating a mechanism for time travel, a "relative spatiality compensator" must be fabricated. The earth rotates on its axis, the Earth undergoes precession, the Earth orbits the sun, the solar system "orbits" along one of the spiral arm of our Milky way galaxy...Calculating an exact place in space at any one time in the past or future would be immensely difficult...without this precision, one could easily "materialize" back in say the 1920s, but 330 feet up in the air...


----------------------------------------------------------------------------------------------------------------------------------------------------------------Rick...
I thought relativity meant it all depends on the reference frame and coordinate system. Like this application should be able to define a system that accounts for the tectonic shifts so that the selected location remains at [0,0,0,t].

I mean, plenty of folks' reference frame revolves around them...
 
I thought relativity meant it all depends on the reference frame and coordinate system ... so that the selected location remains at [0,0,0,t].

The field equations of general relativity permit a closed timelike curve (CTC) along which an object can move through spacetime and eventually return to the exact same coordinates in space and time that it was at previously.

It appears that a CTC would permit a time traveler to travel into the past, but only if it is a past of which the time traveller would have always been a part. This ensures there would be no changes to the past as a result of the time traveler suddenly showing up there.

Annoyingly, if the time traveller can't change history, that would limit the dramatic tension in many science fiction stories!

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The 2004 TV series Lost involved a CTC plotline where a group of characters traveled backward in time, in the hopes of altering events. However, it turned out that their actions in the past create no change in how events unfolded, as it turns out that they were always part of how those events unfolded in the first place. 🤓