Weekly Science Roundup: From Cosmic Rhythms to Pandemic Impacts

This week’s edition of Scientific American Science Quickly, hosted by Rachel Feltman, covers a diverse array of scientific developments, ranging from the mechanical quirks of our planet to the lasting biological imprints of the COVID-19 pandemic.

Earth’s Variable Rotation

Recent headlines have highlighted that Earth’s rotation has been slightly irregular. Specifically, the International Earth Rotation and Reference System Service noted that July 22nd was approximately 0.8 milliseconds shorter than a standard 24-hour day. While these "missing fractions of milliseconds" garnered attention, scientists emphasize that Earth's rotation speed naturally varies. Factors such as "movements of our planet's liquid core," "variations in the jet stream," and the "gravitational pull of the moon" play significant roles. Additionally, a 2024 study suggests that "melting polar ice" has impacted Earth's angular velocity. Although days have generally trended longer over geological time, current fluctuations remain a subject of ongoing observation.

Celestial Events: A Double Meteor Shower

Skywatchers are in for a treat this week as two meteor showers reach their peak simultaneously on the night of July 29th to 30th. The "Southern Delta Aquarids" and the "Alpha Capricornids" will both be active. While the Alpha Capricornids are noted for occasionally producing "bright fireballs," the Southern Delta Aquarids will be particularly visible to those in the Southern Hemisphere. With the moon in a "waxing crescent phase," visibility conditions are expected to be optimal for those looking toward the southern sky, provided cloud cover remains minimal.

FEMA Leadership and Policy Controversy

On the policy front, the Urban Search and Rescue Chief of the Federal Emergency Management Agency (FEMA), Ken Pekurek, resigned following his tenure. Reports indicate his departure was linked to the "delayed response to Texas's recent catastrophic flooding." The controversy centers on a new Department of Homeland Security policy requiring personal approval for spending over $100,000, which reportedly caused a "72-hour" delay in deploying search and rescue teams. Furthermore, lapses in contracts with call center companies meant that during the peak of the flood, FEMA’s ability to answer calls from disaster survivors dropped significantly, with the agency answering only 35.8% of calls on July 6th compared to 99.7% the day prior.

The Pandemic’s Impact on Brain Aging

A significant study published in Nature Communications suggests that the COVID-19 pandemic may have accelerated brain aging across the population, regardless of infection status. Researchers utilized machine learning models to analyze "structural changes" in brain scans from nearly 1,000 individuals. The findings revealed that "signs of brain aging, such as the shrinkage of gray matter," were accelerated globally. This effect was most pronounced among men, older individuals, and those from "socioeconomically deprived backgrounds." Experts hypothesize that pandemic-related factors—such as "increases in stress," "alcohol consumption," and "economic insecurity," paired with decreased socialization—contributed to these biological shifts.

Evolutionary Insights: Ancient Sea Arachnids

Concluding on a note of evolutionary history, a study on the extinct species Melisonia symmetrica, which existed half a billion years ago, offers new insights into the origins of arachnids. By analyzing fossilized remains, scientists discovered that the creature’s brain layout was "more similar to the way modern arachnid noggins are arranged." This discovery suggests that the ancestors of spiders may have originally evolved their neurological structures while living in the ocean, effectively tracing the roots of modern spiders back to ancient marine environments.