Jack Handey had nothing on my daughter where deep thoughts are concerned

Julia's been very interested in the concept of time lately and has spent a lot of time studying clocks and asking questions about minutes and seconds and hours and how they all fit together. She doesn't really get it all yet, but her brain is clearly working overtime to try to figure this puzzle out.

The other night, Paul went in to check on her about an hour after she'd gone to bed and she was still wide awake. "What are you doing," he asked her. "I'm just lying here thinking about time," she answered.

They talked a bit about what time it had been when she'd gone to bed, how much time had passed, and how much remained until the clock moved from 12 back to 1 again (a concept that fascinates her). And then after a short pause, she asked him, "but Daddy, what happens when time runs out and there's none left?"

What indeed. Paul explained that the clock just keeps going around again, day after day, but he said it was pretty clear that wasn't what she really wanted to know. How do you talk about these kinds of things with a 3 year old, particularly when you're still grappling with the answers yourself?