This week, Stu lets us into the secret world of moss, how they're different to other plants, and how they're so hardy they can even survive on the outside of spacecraft; and Claire gets her teeth into a new, large longitudinal study that showed water fluoridation did not harm cognition or IQ. Maeng, Chang-hyun et al., Extreme environmental tolerance and space survivability of the moss, Physcomitrium patens. iScience, Volume 0, Issue 0, 113827 (2025). DOI: 10.1016/j.isci.2025.113827 John Robert Warren et al., Childhood fluoride exposure and cognition across the life course. Sci. Adv. 11, eadz0757 (2025). DOI:10.1126/sciadv.adz0757