Nothing says “Welcome to the future, Philly!” so much as the 500 solar-powered trash compactors now lining city blocks. Fiscally forward-thinking and green, their purchase (via a $2.2 million state grant) may save Philly $875,000 annually, since they require only five weekly pickups as opposed to the 19 the old wire baskets demanded — which also reduces gas emissions. Alas, even brilliant technology can’t trump human nature — more than once, we’ve held onto our trash rather than touch grimy, sticky-looking handles. (Can littering be far behind?) Guess the future is still a bit messy.