


As wellness trends take off, iodine deficiency makes a quiet comeback
Levels of the vital nutrient are falling rapidly in America
A CENTURY AGO, much of northern America was known as the goitre belt. In some regions, anywhere from 26% to 70% of school-aged children had the characteristic neck swellings, or goitres, caused by an enlargement of the thyroid gland. After trials showed that supplements of iodine could prevent goitre, iodised salt was rolled out commercially in 1924, starting in grocery stores in Michigan. By the 1940s, the goitre belt had vanished.

A battle is raging over the definition of open-source AI
Companies that bet on the right one could win big

How blood-sucking vampire bats get their energy
They pull off a trick previously thought unique to a few insects

China plans to crash a spacecraft into a distant asteroid
It will be only the second country to conduct such a planetary defence experiment
Researchers are questioning if ADHD should be seen as a disorder
It should, instead, be seen as a different way of being normal
Airships may finally prove useful for transporting cargo
The problem of variable buoyancy is being overcome
Space may be worse for humans than thought
Why going into orbit sends cells haywire