A somewhat more-fanciful version: Travel into the past is possible, but requires some precondition (e.g. construction of a compatible receiving-unit) which limits the range of travel to periods in which time-travel technology exists.
You could also throw a multiverse-situation on top, where activating the receiver (which instantaneously captures a pending traveler) is actually what causes a branching.
Then it'd introduce a certain game-theory to it all: If you send something back in time, you're essentially losing it (or them) to a parallel universe, and turning on your receiver means accepting a gift from some possible future.
So some people will travel in time for their personal benefit (greeted as a celebrity with valuable skills and knowledge) and others will consider how to transmit all of their radioactive waste to another version of themselves...
Not exactly, thought, since you have to "opt in" to receive an, uh... Secret Schrodinger present, and it arrives at a local time and destination of your choosing. And if nothing comes, that implies all the time travelers that ever will will try traveling "past" you have already done so, implying that the end of the universe is surprisingly near.
Occam's Razor corollary: If it is possible, they are under a Star-Trek-like prime directive not to tell us they are from the future or change anything.
Occam's Razor corollary #2: no one wants to visit this time period because, cosmically speaking, it sucks.
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Occam's Razor answer: Because time travel to the past is never invented because it's impossible.
A somewhat more-fanciful version: Travel into the past is possible, but requires some precondition (e.g. construction of a compatible receiving-unit) which limits the range of travel to periods in which time-travel technology exists.
This is indeed my pet Sci-fi novel take on things.
1) Build time machine 2) Greet time traveler who emerges from machine 3) Time passes 4) Time traveler enters time machine.
Lots of room for shenanigans, Fermi paradox solved.
You could also throw a multiverse-situation on top, where activating the receiver (which instantaneously captures a pending traveler) is actually what causes a branching.
Then it'd introduce a certain game-theory to it all: If you send something back in time, you're essentially losing it (or them) to a parallel universe, and turning on your receiver means accepting a gift from some possible future.
So some people will travel in time for their personal benefit (greeted as a celebrity with valuable skills and knowledge) and others will consider how to transmit all of their radioactive waste to another version of themselves...
http://www.imdb.com/title/tt0112167/
Not exactly, thought, since you have to "opt in" to receive an, uh... Secret Schrodinger present, and it arrives at a local time and destination of your choosing. And if nothing comes, that implies all the time travelers that ever will will try traveling "past" you have already done so, implying that the end of the universe is surprisingly near.
Occam's Razor corollary: If it is possible, they are under a Star-Trek-like prime directive not to tell us they are from the future or change anything.
Occam's Razor corollary #2: no one wants to visit this time period because, cosmically speaking, it sucks.
Occam's Razor corollary: Time Travel is only permissible into the future due to entropy.