October 22, 2024: We are covering the leap second, anosmia and microbes that eat cleaning supplies. —Robin Lloyd, Contributing Editor | | | An artist's illustration of Earth as it may have been during the Archean eon between 3.8 billion and 2.5 billion years ago, a time of violent asteroid impacts and volcanic eruptions. Back then, all life on Earth was microbial, with one of its few obvious signatures being microbe-built formations called stromatolites that littered shallow coastal waters. Mark Garlick/Science Photo Library/Alamy Stock Photo | | | • An ancient asteroid impact 3.26 billion years ago vaporized rock that rained down as molten droplets and boiled the ocean. If an asteroid like that hit Earth today, "it would be a complete reset of life, back to the bacterial level." | 8 min read | | | For the first time, global timekeepers soon might decide to subtract one "leap second" from the atomic clocks used to standardize precise readings of time, rather than adding a second, according to a story by Scientific American editor Mark Fischetti and illustrator Matthew Twombly. Since 1972, a total of 27 seconds each was added to account for a tiny lengthening of the time it takes for Earth to make one rotation around its axis. That lengthening was caused primarily by tidal friction. But a couple of factors might counterbalance and ultimately reverse that trend in the coming years. One research team projects an inaugural leap-second subtraction in 2029.
How it works: Calculations of Earth's rotational speedups and slowdowns now are complicated by climate change. As polar glacial melt increases, the additional water spreads beyond ice caps and toward Earth's equator, thereby slowing the planet's rotation. Think of a skater's spin—it slows as the skater extends their limbs from their central axis.
Why it matters: A leap-second adjustment in 2012 was blamed for one airline's flight delays and for temporarily taking down the website Reddit. Although the Internet, automated stock trading and GPS (global positioning system) also rely on atomic clocks, some experts think that frequent micro-time adjustments are unnecessary. | | | Inability to Smell Affects Breathing | People with congenital anosmia, that is people born without a sense of smell, seem to breathe differently than those with a sense of smell, according to a new small study covered by freelance writer Hannah Docter-Loeb. Anosmic people take fewer micro-sniffs to sample the surrounding air and overall have different breathing patterns. A wearable device allowed for continuous 24-hour monitoring of study participants' nasal outflow as they went about their daily activities, both awake and asleep.
Why it matters: Anosmia already is tied to depression, cognitive decline and a shorter life span. Now it appears that breathing differences might play a mechanical role in bringing about these negative health outcomes among people with anosmia. Interest in anosmia has increased as many people globally have suffered from the condition following an infection with COVID or other viruses.
What the experts say: "This research lays the groundwork for future interdisciplinary collaborations that will be crucial in fully understanding and addressing the wide-ranging impacts of anosmia, particularly in diseases like Alzheimer's, where the intersection of anosmia and respiratory function could exacerbate cognitive decline," says chemosensory researcher Paule Joseph. | | | • The treatment landscape for people with addictions has shifted in recent decades, raising questions about the practices and effectiveness of residential treatment facilities, aka rehabs. Meanwhile, evidence justifies the medical treatment of opioid addiction with medications such as methadone and buprenorphine, write physicians Zoe Adams and Sarah Wakeman. Patients with addictions should have expanded access to treatment options that include medication treatments, behavioral therapies, harm reduction interventions and in some cases permanent affordable housing, the authors write. | 5 min read | | | I had occasion to rent cars fairly often in the past year or so. One vehicle initially stymied me with a push-button automatic transmission, a new experience for me. After I related this experience to my spouse, for weeks, he periodically chirped "Push de button!" in a manner that both made me giggle and reminded me how to operate the rental car I was no longer driving. Later, by way of partial explanation, he shared this video of Lena Horne tearing up the joint in 1958. "It's about technology anyway," he said. | —Robin Lloyd, Contributing Editor | | Subscribe to this and all of our newsletters . | | | | Scientific American
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