AN: This one takes place just after the episode 1969.

Flares

The hot dogs had been consumed, the chips and veggies munched on, and the group in Jack's backyard for a barbeque had moved indoors to relax on the couch and chairs with their beers.

"Ahh. This is excellent, Jack." Hammond remarked as he leaned back. "But it doesn't mean that you get out of paying me back."

"Oh, let me take care of that, sir." Jack got up, left the room for a few minutes, and then was back, just in time to hear his CO say, "I was just teasing."

"It's no problem at all though, sir. I got the money from the bank this afternoon. Here you go, General. Five hundred, thirty-nine dollars and fifty cents."

"Jack... you don't really have to pay me back, son. I really was just teasing. That fifty bucks is a small price to pay for getting you back."

Jack grinned. "It's a small price to pay to be back, sir, and one that I'm happy to pay. But since we're talking about our little trip... there's something that's been bothering me since we got home." He paused to take a deep breath.

"General, Carter," Jack stared at each of them for a few seconds. "How on earth could you have known which flares would send us home?"

"Did not Captain Carter already explain that General Hammond would easily be able to look up the required information, O'Neill?" interjected Teal'c.

"She did, she did." Jack nodded. "But there's just one problem with that theory. For the General to be able to look up flares on the opposite side of the sun from the ones that sent us back, he'd have to first know which side they were on when they sent us back. Which he couldn't possibly know until we were already gone. Which means he would have had to write the note before he knew, which... brings me back to my original question. How did you know which flares?"

"It's quite simple, Jack." The general took a long swig of beer and enjoyed the look of frustration on his subordinate's face. "I knew to write:

George. Help them.

August 10, 9:15am

August 11, 6:03pm

because I still had a copy of the original note I had received thirty years earlier. I just had to trust that the other me knew what he was talking about."

Jack was flabbergasted. His mouth hung open for several seconds before Carter spoke up.

"Oh come on, sir, you really shouldn't tease him so. You asked about the rotational difference so many times when you had me do the time travel research that I'm pretty sure you could explain it as well as I could."

"That's true, I probably could explain how the rotational difference affects the time travel... but as Jack pointed out, that wouldn't help me if I didn't know which side of the sun the flares were on that sent you back. I was able tot use that information to double check what was in the note after you left, but I never did figure out how I was supposed to know which side of the sun I needed flares on. Mostly because of the rotational difference- how would I know I wasn't sending you further back in time?

"In the end, I just had to trust myself. At least until you went through the gate. Then I spent three and a half hours on the phone to NASA to make sure that the flare you went through was on the opposite side of the sun. But Jack is entirely right; I didn't know before you left."

"So... " Daniel was still trying to figure it out. "How did the original you know?"

"The original me?"

"Yeah, the first one to send the note. How did he know?" Jack asked, looking at the general again.

"I believe it may have been a causality loop, sir," Carter interjected.

"But wouldn't there have to be a Hammond somewhere who started it?" Jack asked.

"Not necessarily, sir."

"So it was just luck then?" Daniel asked. "Nobody knew before we got back if it would work? Nobody even had a scientific reason to hope that it would?"

"The general thought it would work because it appeared to have worked in the past. I thought it would work because of the general's note."

"But nobody knew?"

"Well, no... the Hammond in the past knew what the Hammond in the future wrote, and the Hammond in the future knew what to write because he'd read the note he was going to send as the Hammond in the past. That's the way a causality loop works- cause and effect get all messed up."

"That's rather... disconcerting," Daniel concluded.

"Yeah," agreed Jack. "Like hearing the splash as your heater falls into the lake while you're ice fishing."