November 13, 2023: Happy Monday. Let's rev up our minds for the week with nuclear clocks, Milky Way astronomy and genomic screening questions. —Robin Lloyd, Contributing Editor | | | A practical and ultraprecise "nuclear clock," even more precise than the atomic clocks that currently underlie the navigation of satellites and motor vehicles, may be within reach, recent breakthrough measurements suggest. Atomic clocks typically rely on lasers to excite electrons orbiting atomic nuclei. The electrons jump or "transition" to a higher energy level before falling back down to a lower one at rapid, regular time intervals—an atomic clock's "tick." In the new study, physicists achieved a first, measuring the transition of particles — protons and neutrons —inside the nucleus of a synthetic isotope called thorium 229. This isotope is a specific type of the weakly radioactive element thorium.
Why they did this: Environmental factors can affect how electrons bounce, making atomic clocks imperfect. So physicists had proposed moving the timekeeping inside the nucleus, where particles are insulated from such interference. It was theorized that thorium 229's nuclear particles could transition into an excited state with a uniquely low amount of energy, making it the only isotope that current laser technology could feasibly excite for a nuclear clock. The measurements confirmed that thinking.
Why this matters: The world runs on ultraprecise timekeeping, usually based on atomic clocks. The enhanced precision of a nuclear clock eventually could lead to advances in nuclear physics and the quantum sensor technology used for satellite navigation and telecommunications.
| | | Some sky-watchers say that the constellation Sagittarius looks like a teapot, and that a glowing blob bulging out of the Milky Way near the constellation, as seen from Earth on a dark night, resembles steam emitted from the teapot's spout. In the Northern Hemisphere, this fanciful interpretation of stellar patterns is best viewed during the evening hours of August. A recent essay by astronomer and science communicator Phil Plait takes its inspiration from such visions to explore the history of thinking about the causes of the Milky Way's glow, the galaxy's true shape and our place in the universe.
The journey: Galileo's telescope and observations confirmed earlier hypotheses that the soft luminescence of the Milky Way was "the collective glow from myriad stars that were too faint and close together in the sky to be individually distinguished" by earlier observers, Plait writes. But it was only in recent decades that measurements of the movement and distances of gas clouds in our galaxy revealed its "vast disk with a central bulge—the same lumpy blob seen toward Sagittarius—that has star-spangled spiral arms winding around it," he adds.
The destination: Plait concludes: "When you stand outside and take in the Milky Way over your head, remember that you live in the stellar suburbs of an enormous spiral galaxy's dust-strewn disk, which is more than a quintillion kilometers across and stuffed full of hundreds of billions of stars and perhaps trillions of planets." | | | • The first commercial direct-air capture facility for removing carbon dioxide from the atmosphere has opened in the U.S., showcasing the potential of a nascent industry. | 3 min read | | | Credit: John Knight; Source: "Rising Wildfire Risk to Houses in the United States, Especially in Grasslands and Shrublands," by Volker C. Radeloff et al., in Science, Vol. 382. Published online November 9, 2023 | | | • Multiple genomic newborn screening studies are launching worldwide, but the evidence for how to best expand such screenings is not yet available, write two clinical geneticists in a new essay. Newborn screening programs can deliver life-saving diagnoses with quick turnaround times and at low cost, write Richard Scott at Genomics England and Zornitza Stark at the Victorian Clinical Genetics Services. However, many questions remain such as equity of access and the selection of conditions for which to screen. There also is insufficient clarity surrounding the definition of treatability and appropriate consent, the authors write. They conclude: "With the technological barriers now largely resolved, we must generate high-quality evidence to inform public policy." | 5 min read | | | As a runner, I took notice of recent stories about a ketchup-maker promoting the use of ketchup packets for quick energy boosts during endurance sports activity. Dieticians and coaches say this is not a good idea. For starters, the arithmetic makes it impractical. Each packet or tablespoon of ketchup packs a heavy dose of sodium and just two to five grams of carbohydrates, whereas most coaches say to consume between 30 and 60 grams of carbohydrates per hour. And let's also acknowledge the environmental impact of packet and "sachet" trash. Coaches and other specialists generally say that athletes might want to stick with gels, applesauce pouches, lemonade, iced tea, energy "chews" or other types of candy. I haven't found much that works well. So, it might not be ideal, but I tend to just run and then eat and drink a lot later. | —Robin Lloyd, Contributing Editor | | Subscribe to this and all of our newsletters . | | | | Scientific American
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