There are times (pun intended) when I think like a time-traveler. In particular, I think about what the world would be like if time travel was possible.

For example, if time travel was possible, you would expect that there would be attempts to change erstwhile-historical events. And so I wonder -- what would be examples of attempts to change things?

One thing that has come to mind more than once is Apollo 13. Suppose that LM-7 was the one and only LM whose ascent engine had a hidden flaw, which would have caused it to fail to ignite (or worse, fail shortly after ignition)? And suppose that you don't have the ability to go back and fix the LM, but you do have a very short window in which you could effect some other small, minor change?

Might you not make a change which would prevent the use of that particular LM's ascent engine in flight? Such as re-attaching a bolt on a service module's oxygen tank shelf just before it was due to be removed from its SM?

I keep wondering how many serious, eye-opening but yet non-fatal accidents might have been engineered to prevent worse events? It's a modus operandi that I might adopt, under similar circumstances...

-the other Doug

This is the classical time travel/alternate history theme where a small change causes a large result. Isaac Asimov probably wrote the ultimate story in this genre "Z as in Sebatinsky" where a change of one letter in one name prevented a nuclear war.

There is a real historical incident which has always fascinated me in this connection. One can make a strong case that the japanese would have won the battle of Midway if it hadn't been for a recce floatplane from the heavy cruiser Tone that was delayed for about half an hour by a catapult problem. Now sabotaging a catapult on a blacked-out warship at night shouldn't be too difficult for a time-traveler.....

Now that reminds me of another Asimov story that suggested that Kilroy was a time-travelling historian that was a specialist on WW 2.

A different game I like is to pretend you're an "accidental" time traveller from about 1967. How long does it take before you figure out that you're in the future -- not just in some other state or something?

So cars do look different, but not THAT different. (Contrast the time traveller from 1927 who ends up in 1967 and knows he/she is in the future almost immediately.) Freeway looks the same -- even the signs are similar (take him from 1972 or so and the signs are identical). AM/FM radio is the same. TV has way more channels, but the shows aren't all that different. (In fact, lots of them ARE THE SAME SHOWS.)

Where are the flying cars? The computers that can talk to you? The vacations on the moon?

Given the huge changes from 1927 to 1967, it seems like things almost stopped from 1967 to 2007 . . .

--Greg

Greg,

PLEASE keep an eye open for a BBC series called "Life On Mars" appearing on your cable BBC channel or some other channel... you'll LOVE it! Modern, PC cop finds himself in the decidedly un-PC 1970s... absolute classic TV, intelligently written, very funny, and a nostalgia-fest too.

I remember one episode of Deep Space Nine where one character (O"Brien, I think) gets stuck in some sort of time loop and keeps bumping into himself. He becomes so annoyed by it that he finally proclaims, "I hate time paradoxes!!"

I think Fritz Lieber got it right in The Big Time. If time travel were possible there'd be constant chaos as vying factions tried perpetually to change the Universe to suit themselves. No thanks!