"Well, I didn't exactly plan it," she said. "It's ... think of it this way. A 'year' on the planet Venus isn't the same length as that on Earth. There are 243 Earth days per Venus day. So if you were able to live on Venus, your time would 'move' differently."
It was the simplest way she could think of to explain it, even if it didn't necessarily apply to what was happening here.