SPONSORED BY  | | | | February 20, 2024: Devastating fires in Colombia, the tumultuous origin of the Milky Way and Charlotte the stingray gets pregnant by herself. —Andrea Gawrylewski, Chief Newsletter Editor | | | A woman attempts to put out a forest fire in Bogota on January 25, 2024. Credit: Raul Arboleda/AFP via Getty Images | | | Fire in Biodiversity Hotspot | More than 500 fires have burned across Colombia since the beginning of the year, consuming at least 42,000 acres of forest and grasslands and choking the residents of Colombia's capital, Bogotá, with a blanket of polluting smoke. Colombia sees 100 to 300 wildfires in a typical January (the height of summer in the Southern Hemisphere); this year marks the first time the month's total exceeded 500 fires in more than 25 years. A study last month found that climate change is the primary cause of the drought now affecting the wider Amazon region.
Why this matters: Colombia is home to nearly 10 percent of the world's biodiversity, with crucial ecosystems ranging from the Andean highlands to the rainforest basin to the Andes' unique and delicate high-altitude wetlands, called paramos.
What the experts say: Higher temperatures, longer droughts and more fires are expected in the years to come. "Paramos are very special ecosystems in terms of their restricted distribution, their hydrologic functioning and the endemic species that live there, but they are also extremely fragile," says Rueda Trujillo, who is now a Ph.D. candidate at Leiden University in the Netherlands. | | | A police officer combats a forest fire in Nemocon, Colombia on January 24, 2024. Credit: LUIS ACOSTA/AFP via Getty Images | | | Astronomers long thought that the Milky Way galaxy was stable since its birth some 13 billion years ago. But recent data from surveys, especially the European Space Agency's Gaia spacecraft, reveal that the Milky Way was built up over a series of tumultuous collisions and mergers with other cosmic objects. As of 2023, Gaia had mapped 1.8 billion stars. And by analyzing the chemical composition of stars, particularly the abundance of metals, astronomers can estimate their age.
What they've found: Astronomers have discovered 60 "stellar streams" in the outermost regions of the galaxy's halo, suggesting that our galaxy has merged with smaller ones in the past. The data also reveal details about gas structures in the galaxy, including the filamentous Radcliffe Wave which is an area of alignment of star nurseries that undulates in the plane of the Milky Way. A batch of stars called the "Sausage" was discovered in the galaxy's halo, but the stars' metal-rich composition is what you'd expect to find in the Milky Way's disk. Scientists think the Sausage stars are remnants of a collision of our galaxy with another galaxy called the Gaia-Enceladus Sausage, about 8 billion to 10 billion years ago.
What the experts say: The result of all this data is a high-resolution movie of a few billion stars in motion. It's "the single largest increase in astronomical knowledge in, like, forever," says Charlie Conroy, a professor of astronomy at Harvard University. "It's been shocking." | | | As other galaxies, dwarf galaxies and clumps of stars called globular clusters approached the Milky Way over the eons they would merge with it. This illustration is an atlas of those mergers. Credit: S. Payne-Wardenaar/K. Malhan, MPIA | | | • Insurance policies are becoming a more common conservation tool for protecting natural ecosystems like coral reefs in Hawaii, Fiji and Mexico. | 3 min read | | | • Fragments from Asteroid 2024 BX1 that exploded over Germany last month turn out to be a rare meteorite type and are as old as the solar system. | 3 min read | | | • Charlotte, a stingray living without a mate in a small North Carolina aquarium, is pregnant via parthenogenesis, or asexual reproduction. She is the first round stingray known to undergo parthenogenesis. | 3 min read | | | The Science Behind RSV and Vaccination | For 60+ years, respiratory syncytial virus (RSV) prevention has evaded scientists. But now that's changed. Dr. Temi Folaranmi, Vice President and Head, US Medical and Clinical Affairs, Vaccines, GSK, sheds light on innovations that led to scientific advances in the prevention of RSV. Learn more. | | | • The Uniform Determination of Death Act (UDDA), the legal standard for death throughout the U.S., has deficiencies and needs to be revised with specific standards around brain death, writes Ariane Lewis, director of neurocritical care at NYU Langone Medical Center. "Society needs a clear legal standard that is consistent with medical practice throughout the country," she says. | 4 min read | | | Last week I wrote about the surprising, violent formation of our solar system. And now, astronomers have discovered that the Milky Way galaxy also had a turbulent past. Growing up in this universe is not a lighthearted affair for cosmic bodies, it seems. | The March issue of Scientific American went live today online. If you're enjoying Today in Science, why not try out a 90-day subscription to the magazine for just $1? You'll be able to dive deeper on a lot of the content I write about in this newsletter. Send any questions to me at newsletters@sciam.com. See you tomorrow! | —Andrea Gawrylewski, Chief Newsletter Editor | | Subscribe to this and all of our newsletters . | | | | Scientific American
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