"They can sometimes," Merry said, watching her interest spike. It made sense that the immortality issue would be the biggest draw. It had been one of the things that freaked Merry out the most when she'd first learned about it. Immortality did not make sense; it was an impossibility in the same was as perpetual motion was an impossibility. But clearly it wasn't, which meant rearranging some pretty fundamental laws of the universe. And since no one else had managed to explain those laws, Merry had been thinking lately she should start getting into physics. "But generally, from what I've read, they last forever. It's terrifying," she added, shaking her head a little.