I watched "The Final Countdown" again yesterday: a pretty average film, but great footage of aircraft carrier operations and aircraft. Good ending, especially for the dog.
The plot involves the modern USS Nimitz on exercises near Pearl Harbour, which runs into a weird vortex which takes it back to 6 December, 1941. Recce aircraft find the US fleet as it was then and the Japanese fleet steaming towards Pearl.
The interesting question, discussed in the film, is what should they do?
One issue with time travel (which, according to Einstein and Prof Brian Cox, is possible) is that if you changed events, history would be different and various things and people would not exist.
If Nimitz' aircraft attacked the Japanese fleet, the tragic events at Pearl Harbour would have been avoided, but Japan would have declared war on the US for destroying its fleet. However, the Pacific war would have turned out quite differently, with, say, no invasions of New Guinea, the Philippines and the various islands.
Interesting to contemplate; many lives would have been saved and created by service men and women who survived, and the world would be quite different; and possibly, the Nimitz wouldn't exist, in which case it couldn't have travelled back in time.
Too much for me - like Bill Bailey when reading "A Brief History of Time', I have to take a break and eat a Pringle sandwich!
Geoff
The plot involves the modern USS Nimitz on exercises near Pearl Harbour, which runs into a weird vortex which takes it back to 6 December, 1941. Recce aircraft find the US fleet as it was then and the Japanese fleet steaming towards Pearl.
The interesting question, discussed in the film, is what should they do?
One issue with time travel (which, according to Einstein and Prof Brian Cox, is possible) is that if you changed events, history would be different and various things and people would not exist.
If Nimitz' aircraft attacked the Japanese fleet, the tragic events at Pearl Harbour would have been avoided, but Japan would have declared war on the US for destroying its fleet. However, the Pacific war would have turned out quite differently, with, say, no invasions of New Guinea, the Philippines and the various islands.
Interesting to contemplate; many lives would have been saved and created by service men and women who survived, and the world would be quite different; and possibly, the Nimitz wouldn't exist, in which case it couldn't have travelled back in time.
Too much for me - like Bill Bailey when reading "A Brief History of Time', I have to take a break and eat a Pringle sandwich!
Geoff
Time travel into the future is trivially simple at a rate of 1 second per second, travel at a substantial fraction of lightspeed or in a strong gravitational well and you can slow that rate predictably. I have read Einstein widely and do not recall him suggesting that travel into the past is possible, the causality conundrum it raises strongly suggests it's a topic for sci-fi alone.
All of physical reality exists inside the "light cone" of a Minkowski spacetime diagram:
The red "worldline" represents our path through spacetime, while the sloping sides of the light cone represent the worldlines for photons travelling at the speed of light.
The region outside the light cone (labelled "elsewhere") is inaccessible because one would have to travel faster than light to reach it.
However, hypothetical faster than light particles called tachyons could travel through this inaccessible region and send a signal from the future into the past.
https://www.space.com/tachyons-facts-about-particles
Note that I said "signal" and not "aircraft carrier"! 😀
The red "worldline" represents our path through spacetime, while the sloping sides of the light cone represent the worldlines for photons travelling at the speed of light.
The region outside the light cone (labelled "elsewhere") is inaccessible because one would have to travel faster than light to reach it.
However, hypothetical faster than light particles called tachyons could travel through this inaccessible region and send a signal from the future into the past.
https://www.space.com/tachyons-facts-about-particles
Note that I said "signal" and not "aircraft carrier"! 😀
I feel that the captain (Kirk Douglas) wimped out. Such a disappointment. 🙁
The movie has amazing footage of the Nimitz, and feels very real for that part of it.
The movie has amazing footage of the Nimitz, and feels very real for that part of it.
Let's say there's a bad person; if you go back in time and kill them, or stop them, perhaps what eventually stopped them wouldn't have happened, and their beliefs would still be popular, and do more damage in the long run than the original time line.
In an episode of Red Dwarf, the crew go back in time and accidentally kill the killer of JFK, but this starts another time line that is worse, so the take the future JFK and convince him to shoot himself, because in our time line he is highly regarded, but in the alternative time line (in which he doesn't get shot) he goes on to be a bad guy.
What would happen is you saved Buddy Holly, John Lennon, or Kurt Cobain? Would they have made more outstanding music, or gone on to make terrible stuff that would mar their reputation?
What would happen if you went back to Birmingham, and stopped a guy mashing his fingers in a press?
In an episode of Red Dwarf, the crew go back in time and accidentally kill the killer of JFK, but this starts another time line that is worse, so the take the future JFK and convince him to shoot himself, because in our time line he is highly regarded, but in the alternative time line (in which he doesn't get shot) he goes on to be a bad guy.
What would happen is you saved Buddy Holly, John Lennon, or Kurt Cobain? Would they have made more outstanding music, or gone on to make terrible stuff that would mar their reputation?
What would happen if you went back to Birmingham, and stopped a guy mashing his fingers in a press?
Part of the fun of the final countdown is trying to decide what I would do.
What would have happened in Europe without the Pearl harbor attack? Would the US have rallied like it did if we had thwarted an attack from Japan?
The what would you change and what would the affect be questions are fun.
There was an episode of a show called Timeless where they had the opportunity to save Lincoln and opted not to because it would have changed too much.
The show 11.22.63 also dealt with the Kennedy assassination and by stopping it they ended up with things much worse.
In About Time the character comes back from traveling to the past and finds he now has a daughter instead of a son. Everything else is the same. The smallest change was enough to alter that.
What would have happened in Europe without the Pearl harbor attack? Would the US have rallied like it did if we had thwarted an attack from Japan?
The what would you change and what would the affect be questions are fun.
There was an episode of a show called Timeless where they had the opportunity to save Lincoln and opted not to because it would have changed too much.
The show 11.22.63 also dealt with the Kennedy assassination and by stopping it they ended up with things much worse.
In About Time the character comes back from traveling to the past and finds he now has a daughter instead of a son. Everything else is the same. The smallest change was enough to alter that.
We all live in separate spacetime tunnels to some degree. But we tend to believe we all live in the same spacetime.
Time travel happens in your head when you can't keep different, incompatible coordinate systems apart;-)
I would start with Galileo's relativity;-)
I would start with Galileo's relativity;-)
According to one of the The Hitchhiker's Guide to the Galaxy books, the main problem with time travel is that it leads to very complicated verb tenses.
Not Einstein, it was Kurt Gödel who found closed timelike loops in general relativity. Einstein was bewildered.
Indeed! If you move through space it uses up some of your spacetime velocity, leaving less for your travel through time.
That's why a moving clock ticks more slowly than a stationary one.