September 17, 2025—How a billionaire's plan to reach another star fell apart. Plus, the secret lives of dead trees, and a new dinosaur species is discovered. —Andrea Gawrylewski, Chief Newsletter Editor | | Zavacephale rinpoche skull. North Carolina Museum of Natural Sciences | | The Breakthrough Starshot announcement even in April 2016 included, from left, documentary writer and producer Ann Druyan, Zachary Manchester, Yuri Milner, Stephen Hawking, Freeman Dyson, Mae Jemison, Pete Worden, Avi Loeb and Philip Lubin.Bryan Bedder/Getty Images for Breakthrough Prize Foundation | | In 2016 billionaire Yuri Milner hosted a press conference to announce Breakthrough Starshot: a project that would eventually take human technology to another solar system. The plan was to launch tiny probes called "lightsails" that would be propelled by lasers to travel at 20 percent the speed of light. At that rate the spacecrafts would reach the closest star to Earth, Proxima Centauri, in a couple of decades. Milner pledged $100 million toward the project and brought on prominent physicists and engineers to work on it. But in the more than 10 years since the inaugural meeting, only preliminary progress has been made on the plans, and communications from the Breakthrough organization have ceased. According to Philip Lubin, a University of California, Santa Barbara, physicist on whose research much of the Starshot dream was based, the $100 million never came through. He calculated that, overall, roughly $4.5 million was awarded to about 30 contracts. Other scientists involved in the project say they haven't heard from the project leaders in "probably two years." Why this happened: Engineering an interstellar journey is almost ludicrously difficult, writes reporter Sarah Scoles who investigated the quiet demise of Starshot Breakthrough. "With today's rocket technology, it would take thousands of years to get to the nearest star. Processes and components need to be invented, iterated on and vetted, at great expense, most likely over decades," she writes. Chief on the list: how to communicate signals back to Earth from light-years away. Plus, the cost and logistics of developing a new laser system to propel the lightsails. And, developing novel materials needed for the lightsails themselves. What the experts say: Sure, "$100 million sounds like a lot of money," says Edwin Turner, an emeritus astrophysicist at Princeton University and one of the first people to be involved in Breakthrough Starshot. "It's certainly more than pocket change for most of us, but it's not really very much for huge technological programs." "If there was a one-sentence summary of what Breakthrough was and did," Lubin says, "it was to bring attention to the dream." | | Mark Harmon gently pulls up a section of a tree carcass to reveal how deeply it has decomposed. Chris Gunn | | If a tree dies in the woods, does it even matter? Mark Harmon, a researcher at Oregon State University, has been watching more than 500 trees decay in six forest sites for the last 40 years. What he has discovered is remarkable: Deadwood might remain on a forest floor or stand upright for anywhere from three to 750 years. In a 2020 analysis, Harmon and his colleagues estimated that dead tree decay rates can vary by a whopping 244-fold across species and climates. Why it matters: Deadwood rotting rates determine how quickly the carbon in that tree is released into the atmosphere, so a forest dominated by slow-rotting species can hold enormous stores of carbon for decades or centuries, whereas quickly decaying species can release lots of carbon into the air. Extrapolated to a global level, carbon sequestration and emission by dead trees can significantly affect the amount of CO2 in the atmosphere and therefore influence climate change. Dead trees and the soil surrounding them also interact, altering the carbon concetration in the tree's stores. What can be done: Scientists used to assume that decomposition was instantaneous, Harmon says—that when a tree dies, it essentially disappears. "But that's not true anywhere on Earth, and it's never been true," he says. A dead tree is "just a transition to something else."
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