We find out how long it takes for a comet to melt and we ask could we ever get a cometless sky? Plus we wonder the power of plants. Like this podcast? Please help us by <a href="https://www.thenakedscientists.com/donate">supporting the Naked Scientists</a>

Can we acheive artificial photosynthesis?

Each week we set out to solve one of the world's weirdest, wackiest, funniest and funkiest scientific puzzles. And along with the answer there's a brand new question to think about for next time...