Researchers propose that an exploding comet near Earth's atmosphere could have caused widespread fires and environmental changes, leading to the collapse of the Clovis culture and Ice Age fauna. This theory is supported by findings of shocked quartz, rare earth elements, and nanodiamonds near Clovis sites. Separately, scientists have developed a 'lung-on-a-chip' using stem cells to simulate human lung behavior, offering a new tool for disease research and personalized drug testing without animal models.