We flock to beaches for it, cats and other animals bask in it, the quality of photographs lives and dies by it, and a person’s mood (and vitamin D level) gets a boost from it. Although it has known risks, sunlight also seems to hold immense restorative value. Now scientists are finding the sun’s rays could truly help to quash some autoimmune diseases. In our cover story, journalist Rowan Jacobsen introduces us to Kathy Reagan Young, who was diagnosed with multiple sclerosis (MS) in 2008 and took up phototherapy relatively recently. She stands in front of a light box every morning, her torso engulfed in ultraviolet rays for just minutes at a time. Since starting the therapy, her brain fog and fatigue have nearly vanished in what Young calls a “UV-fueled rebirth.” In this hopeful feature, Jacobsen also meets with scientists who are trying to figure out how UV light calms a person’s immune system. Advocates say a better understanding of this process could lead to “an Ozempic for autoimmunity,” he writes, referring to the blockbuster weight-loss drug.
Rather than taking in warming sunbeams, some researchers want to repel them and turn down global temperatures by refreezing a swath of Arctic ice as big as the combined area of Texas and New Mexico. The gargantuan geoengineering project would require half a million underwater drones to pull water from below the melting ice cap and spray it onto the surface to freeze. Climate journalist Alec Luhn recounts his visit to an Inuit village in northern Canada where scientists are testing out the ice-thickening technique. As with all geoengineering ideas, he finds, there’s no guarantee this scheme will work or way to know for certain whether there will be negative consequences. But polar scientists who spoke to Luhn say humanity needs a stopgap until the world can wean itself off greenhouse-gas-emitting coal, oil and natural gas.
The drive to find answers is what propels many scientists. One nagging question remains: Where did we come from? Now cutting-edge radio astronomy is helping cosmologists peer back in time to the very start of the universe, when only Hula-Hooping particles existed. No moon. No Earth. No Milky Way. No light. Scientific American contributor Rebecca Boyle eloquently describes exciting new telescopes and experiments aimed at detecting signals from the wriggling atoms spilling out of these so-called cosmic dark ages. In addition to learning how the universe took shape, scientists hope to get intel on how the first light was released and the first galaxies formed.
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Physicist Matthew von Hippel looks not at the birth of the universe but at its destruction, outlining a disastrous world-ending scenario that makes asteroid strikes and Earth-colliding black holes look like kid stuff. Called vacuum decay, this apocalyptic event would result from the emergence of a new quantum state. Here’s how: The value of the Higgs field that pervades all of space would have to increase—something physicists liken to rolling a boulder up a hill. The field change would manifest in a quantum bubble, which, if big enough, could expand at the speed of light, ultimately making matter—and therefore life—impossible.
Scientists had assumed that all major renovations to our genomes had happened long ago and that any recent evolutionary changes were few and far between. But advances in DNA-sequencing technology have revealed that even in recent millennia, humans have continued to evolve in substantive ways. These changes helped us to conquer every corner of Earth, writes journalist Kermit Pattison. “We are like rats or cockroaches—extremely adaptable,” says one scientist who spoke with Pattison.
If you look up “mitochondria” in a biology textbook, you’ll find a definition that is some variation of “powerhouses of the cell.” But accumulating research shows these organelles are also social beings that orchestrate the inner workings of the cell; they even communicate with and help one another. Of course, when mitochondria malfunction, diseases can ensue. Behavioral neuroscientist Martin Picard’s passionate profile of mitochondria in this issue gave me a lesson in not only the value of basic science but also the wonders of life.
