Freethought & Rationalism Archive

Silent Dave · 12-30-2002, 07:29 PM

Let's say you build a time machine, travel back in time and attempt to shoot your grandfather when he is ten years old -- thus negating your own birth and subsequent actions. How would this paradox be resolved in any decently-run universe?

The Lone Ranger · 12-30-2002, 07:41 PM

Not to be a wet blanket or anything, but I suspect the universe happens to be structured in such a way that time travel to the past can never occur. Thus, the paradox could never arise.

If time travel to the past can occur, I suspect that this would turn out to be true because some form of the "Many Universes" theory is correct. In this case, killing your grandfather would immediately cause a "split" to occur -- one Universe in which you exist; one in which you don't. Or something like that.

Cheers,

Michael

Silent Dave · 12-30-2002, 07:47 PM

The First Law of Pollwriting, Michael: Never let the facts get in the way of a good poll.

Dave

Shadowy Man · 12-30-2002, 07:56 PM

Quote:

Originally posted by The Lone Ranger
In this case, killing your grandfather would immediately cause a "split" to occur -- one Universe in which you exist; one in which you don't. Or something like that.

Quantum mechanically speaking there's nothing special about killing your grandfather. I believe, as long as we are speculating here, that the instant you time traveled to the past you'd be in a "different universe". In that one killing your grandfather is just the same as killing anyone. Hell, you could just bump into him before he accidentally bumps into your grandmother-to-be and you could negate your future existence in that timeline.

Oh, the joys of temporal mechanics.

Witty · 12-30-2002, 07:58 PM

I think The Lone Ranger is right. We don't have to worry about what will happen because it will never be possible.

It was once theorized that by creating a stable wormhole with one mouth on Earth, and one mouth on a spaceship, you could create a time machine by taking the spaceship to a nearby star and back at high speed. Then, due to the results of time dilation, you could travel into the future by going through the wormhole from the Earth mouth to the ship mouth, and into the past by going through from the ship mouth to the Earth mouth.

Unfortunately, a group of physicists curious about this possibility proved that the wormhole would be destroyed by the massive energies created by photons going from one mouth to the other in a curcuit an instant before it became a time machine.

Back to the drawing board, I guess...

Silent Dave · 12-30-2002, 08:57 PM

Darnit. That ruins not one but TWO of my favorite books!

Dave

Jobar · 12-30-2002, 09:35 PM

As the holder of a degree in physics, the possessor of a huge library of science fiction, and the same name as a famous science fiction writer, I can state conclusively that the 'split-off universe' option is the correct one.

Silent Dave · 12-30-2002, 09:41 PM

So sayeth the handyman.

Osiris · 12-30-2002, 09:56 PM

There is no past, there is no future. Only time which exists is NOW.

Godbert · 12-30-2002, 10:02 PM

I would take Grandpa's place and give Grandma a good shag.
Oh yeah, Granny, be my dirty little bitch ...

View Poll Results: How would the Grandfather Paradox be resolved?
The fabric of the space-time continuum would be ripped apart.	3	6.00%
A new timeline would be branched out, preventing your return to the "present."	29	58.00%
You would immediately cease to exist.	3	6.00%
You would take Grandpa's place. (You have his genes, after all.)	1	2.00%
You would not succeed -- your gun would jam, or a stray meteorite would hit you, or something.	14	28.00%
Voters: 50. You may not vote on this poll

12-30-2002, 07:29 PM	#1
Silent Dave Banned Join Date: Oct 2000 Location: Bloomington, MN Posts: 2,209	Dave's Pointless Polls #1: The Grandfather Paradox Let's say you build a time machine, travel back in time and attempt to shoot your grandfather when he is ten years old -- thus negating your own birth and subsequent actions. How would this paradox be resolved in any decently-run universe?

Thread Tools	Search this Thread
Show Printable Version	Search this Thread: Advanced Search

12-30-2002, 07:41 PM	#2
The Lone Ranger Veteran Member Join Date: Oct 2001 Location: Eastern U.S. Posts: 1,230	Not to be a wet blanket or anything, but I suspect the universe happens to be structured in such a way that time travel to the past can never occur. Thus, the paradox could never arise. If time travel to the past can occur, I suspect that this would turn out to be true because some form of the "Many Universes" theory is correct. In this case, killing your grandfather would immediately cause a "split" to occur -- one Universe in which you exist; one in which you don't. Or something like that. Cheers, Michael

12-30-2002, 07:47 PM	#3
Silent Dave Banned Join Date: Oct 2000 Location: Bloomington, MN Posts: 2,209	The First Law of Pollwriting, Michael: Never let the facts get in the way of a good poll. Dave

12-30-2002, 07:58 PM	#5
Witty Junior Member Join Date: Jun 2000 Location: Madison, Wisconsin Posts: 95	I think The Lone Ranger is right. We don't have to worry about what will happen because it will never be possible. It was once theorized that by creating a stable wormhole with one mouth on Earth, and one mouth on a spaceship, you could create a time machine by taking the spaceship to a nearby star and back at high speed. Then, due to the results of time dilation, you could travel into the future by going through the wormhole from the Earth mouth to the ship mouth, and into the past by going through from the ship mouth to the Earth mouth. Unfortunately, a group of physicists curious about this possibility proved that the wormhole would be destroyed by the massive energies created by photons going from one mouth to the other in a curcuit an instant before it became a time machine. Back to the drawing board, I guess...

12-30-2002, 08:57 PM	#6
Silent Dave Banned Join Date: Oct 2000 Location: Bloomington, MN Posts: 2,209	Darnit. That ruins not one but TWO of my favorite books! Dave

12-30-2002, 09:35 PM	#7
Jobar Veteran Member Join Date: Jun 2001 Location: secularcafe.org Posts: 9,525	As the holder of a degree in physics, the possessor of a huge library of science fiction, and the same name as a famous science fiction writer, I can state conclusively that the 'split-off universe' option is the correct one.

12-30-2002, 09:41 PM	#8
Silent Dave Banned Join Date: Oct 2000 Location: Bloomington, MN Posts: 2,209	So sayeth the handyman.

12-30-2002, 09:56 PM	#9
Osiris Junior Member Join Date: Dec 2002 Location: Houston, Texas Posts: 40	There is no past, there is no future. Only time which exists is NOW.

12-30-2002, 10:02 PM	#10
Godbert Senior Member Join Date: Dec 2002 Location: southern california Posts: 779	I would take Grandpa's place and give Grandma a good shag. Oh yeah, Granny, be my dirty little bitch ...

Freethought & Rationalism Archive

The archives are read only.