To find out what was happening to astronauts over longer periods of space flight, NASA put together a 10-team study of twin astronauts Scott and Mark Kelly. Scott spent a year on International Space Station, while his brother Mark lived a relatively normal life on Earth—though both regularly sent the researchers samples of their blood, urine, cognitive test results, and other data to assess their physiology over time. Scott Kelly returned to Earth in 2016, and researchers have been studying and comparing the twins ever since. The conclusion? A year in space caused a cascade of changes in Scott’s gene expression and physiology—some of which remained even after he returned to Earth. Dr. Susan Bailey, a radiation biologist at Colorado State University, explains one surprising mystery: The average length of Scott’s telomeres, a part of DNA that usually shortens with aging or other kinds of stress, increased. And Dr. Christopher Mason at Weill Cornell Medicine explains how spaceflight ramped up genes associated with Scott Kelly’s immune system and what remained different even months after his return to Earth. Patients with Alzheimer’s disease can experience decreased blood flow in their brains caused by white blood cells sticking to blood vessels that can cause a block. Researchers at Cornell University have found that these stalls happen in the tiniest blood vessels, the capillaries. Understanding these capillary blocks could help find new Alzheimer’s treatments—and to do that, the researchers have to look through hundreds of thousands of images of blocked capillaries. Now, you can help. Physicist Chris Shaffer, who is on the Cornell University team, teamed up with Pietro Michelucci to develop a citizen science game called Stall Catchers that uses the power of the crowd to help identify these stalls. They talk about how Stall Catchers can help with their data—and the one-day megathon when you can participate. By 1918, the British naturalist and ornithologist Collingwood Ingram had tired of studying birds, but soon became obsessed with two magnificent flowering cherry trees planted on his property. He went to Japan and hunted for wild cherries all over the country on foot, horseback, and even from the sea, using binoculars to spot prime specimens. Throughout his travels, he became convinced that Japan was in danger of losing its multitude of cherry varieties, through modernization, development, and neglect, and he went on to evangelize for the wondrous diversity of flowering cherries in Japan, and back home in the western world. In The Sakura Obsession, Japanese journalist Naoko Abe tells Ingram's story, and the cultural history of cherry blossoms in Japan.