NASA spent years and billions of dollars collecting Martian samples to bring home. Now they might be stranded
Why a Little Heartbeat Irregularity Can Be Good for You
Milliseconds of variability, now detected by fitness watches, can improve well-being
Science Crossword: A Destructive Fix
Play this crossword inspired by the December 2025 issue of Scientific American
Poem: ‘The Covert Herbarium of Cryptogamic Botany’
Science in meter and verse
Can AI ‘Griefbots’ Help Us Heal?
What can AI “griefbots” do for those in mourning?
Can We Find Cleaner Ways to Extract Rare Earth Elements?
These valuable but difficult-to-extract metals are increasingly important to modern life
December 2025: Science History from 50, 100 and 150 Years Ago
Heimlich maneuver; training fleas
Personalized mRNA Vaccines Will Revolutionize Cancer Treatment—If Federal Funding Cuts Don’t Doom Them
Vaccines based on mRNA can be tailored to target a cancer patient’s unique tumor mutations. But crumbling support for cancer and mRNA vaccine research has endangered this promising therapy
How Fossil-Fuel Companies Are Driving Plastic Production and Pollution
To keep profits rolling in, oil and gas companies want to turn fossil fuels into a mounting pile of packaging and other plastic products
Transplant Rejection Is a Major Hurdle for Pig Organs. Scientists Are Solving the Problem
In a successful transplant in a man with brain death, scientists prevented the immune system from attacking a genetically modified pig kidney for 61 days, the longest such an experiment has lasted