The Download: four (still) big breakthroughs, and how our bodies fare in extreme heat

Plus: A CDC panel voted to recommend delaying the hepatitis B vaccine for babies. If you're a longtime reader, you probably know that our newsroom selects 10 breakthroughs every year that we think will define the future . This group exercise is mostly fun and always engrossing, with plenty of lively discussion along the way, but at times it can also be quite difficult. The 2026 list will come out on January 12--so stay tuned. In the meantime, we wanted to share some of the technologies from this year's reject pile, as a window into our decision-making process. These four technologies won't be on our 2026 list of breakthroughs, but all were closely considered, and we think they're worth knowing about.