When you leave a house, it doesn't go away. Whether you travel across the street, across the country, or across the world, the house doesn't change. It's a permanent fixture in the world, whether you're watching it or not. It remains exactly as you left it, waiting for you to return.
Is time like that? Once a moment goes by, does it stay put? Can you somehow return to that small speck of time? Can wormholes, DeLoreans, or little blue boxes catch minutes gone by? Or is the moment gone forever, swept away by a rushing river, preserved only in photographs? Do time's houses remain as you left them, or does time burn them down after you leave? Can you collect time's raindrops in a cup, or can you only watch them drain out of a sieve's bottom?
Until someone can find an answer, we'll have to make do with memories.