Today in Science: Dark matter could be a shadow realm of the universe

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April 2, 2025—Dark matter may be a whole hidden sector of the universe, astronauts launch into polar orbit, and the shingles vax could protect against dementia.   —Andrea Gawrylewski, Chief Newsletter Editor TODAY'S NEWS A SpaceX Falcon 9 rocket carrying the Fram2 mission lifts off from Kennedy Space Center in Cape Canaveral, Florida on March 31, 2025. Gregg Newton/AFP via Getty Images SpaceX's Fram2 mission launched Monday night. It is the first ever to take astronauts into polar orbit, carrying four crew members between Earth's North and South Poles in about 45 minutes. | 3 min read The shingles vaccine may protect against Alzheimer's disease and other forms of dementia, a new study shows. | 3 min read The new leader of the NIH fired four leaders and thousands of employees at the agency. | 4 min read A long-simmering disagreement over the universe's present-day expansion rate (called the Hubble tension) shows no signs of resolution, leaving experts increasingly vexed. | 7 min read State and local emergency responders were warned last week to prepare for FEMA to be abolished or drastically reduced. | 4 min read More News TOP STORIES The Dark Sector For the past three decades, the search for dark matter has come up empty. Astrophysicists know it exists–they've measured the gravity of the mysterious substance that fills and shapes galaxies and other large cosmic structures, but which is still transparent to photons. But pinning down precisely what it is still eludes scientists. (Dark matter is not to be confused with dark energy, which is a yet-to-be-identified force pulling the universe apart.)   A new idea: Astrophysicists have embarked on many involved and expensive experiments to try and identify the single particle that might be dark matter. But some scientists hypothesize that, rather than being one type of particle, dark matter might be a whole new sector of particles and forces. "There could be dark atoms—made of dark protons, dark neutrons and dark electrons—held together by a dark version of electromagnetism," writes Kathryn Zurek, a theoretical physicist at the California Institute of Technology.   How it works: Dark matter particles could occupy a so-called hidden valley of the energy scale. The dark sector particles would exist at lower energies than some traditional hypothesized dark matter particles such as WIMPS (weakly interacting massive particles). To find the hidden valley, physicists need a "connector," that is, an interaction between dark matter and regular matter that can tunnel between the accessibility barrier between them.    Jen Christiansen Next steps: To produce a connector, Zurek and colleagues have begun experimenting with so-called polar materials, like sapphire and quartz, which produce strong phonons (a unit of vibrational mechanical energy) that seem like they would interact well with dark photons. Such materials would need to be placed in very quiet and contaminant-free environments. Setting up such experiments could take years.    Explore the dark sector: Next week, Zurek will sit down with Scientific American senior space and physics editor Clara Moskowitz for a digital discussion about the hidden world of dark matter. This event is open to Scientific American subscribers only, so if you're already a subscriber, log in to your account to sign up.

Dark matter is the hidden mass of the universe. But what if it's more mysterious than we thought? Join theoretical physicist Kathryn Zurek and science journalist Clara Moskowitz to learn about the latest research and compelling findings.   Sign Up!

EXPERT PERSPECTIVES Last week, Trump administration officials leaked plans and rationale for bombing Yemen on a group chat on Signal (which also included the editor in chief of the Atlantic magazine). This is a prime example of "groupthink" in political psychology, writes Dan Vergano, senior opinion editor at Scientific American. First described in 1972, "groupthink leads to premature decisions, often bad ones, spurred by conformity within groups where any one person feels that disagreement is impossible," he says. | 5 min read More Opinion WHAT WE'RE READING A marine biologist discovered an octopus with a brood of babies living in the bottom of a bottle on the seafloor off the Florida Keys. | Vox ProPublica wanted to talk to people working in the federal government. So it bought an LED billboard truck. | NiemanLab The work of the eclectic American futurist Alvin Toffler has had a strong influence on China's digital transformation since the 1980s. | The New York Review For decades, physicists have been trying out and testing many different hypotheses to explain dark matter—the two leading candidates are WIMPS and axions, both particles. In the next decade or so, experiments will begin to test these particles' mass ranges. Whether by route of a single particle or an entire sector of particles and forces, the hunt is ramping up. The universe is a dark place, but we are lucky to live in a bright spot. Thank you for joining me on an illuminating journey of science discovery. Send any thoughts or suggestions to: newsletters@sciam.com.    —Andrea Gawrylewski, Chief Newsletter Editor

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