SETI THE RECORD STRAIGHT
In “We Probably Aren’t Alone,” Sarah Scoles describes how Italian astronomer Giovanni Schiaparelli’s 1877 observation of apparent “channels” or “grooves” on Mars had led to a widespread belief that the planet was “home to canal-digging civilizations” thanks to a mistranslation. Scoles notes that this idea “began to lose its sparkle in 1909, when French astronomer Eugène Antoniadi” found that the lines Schiaparelli saw were an optical illusion.
The same finding as Antoniadi’s was made three decades earlier. In the February 2024 issue of the Journal for the History of Astronomy, I published an article on the history of astronomical observations made on the island of Madeira. In it, I point out that, in 1877, the same year as Schiaparelli’s claim, amateur astronomer and professional artist Nathaniel Everett Green took advantage “of the transparency of the Madeira air” to observe Mars, as he wrote in the Memoirs of the Royal Astronomical Society in 1879. He noted that “it would be difficult to exaggerate the keen map-like appearance of the planet,” which allowed him to conclude that “the remarkable dark canals … of Professor Schiaparelli … certainly were invisible at Madeira.”
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Green invoked an optical illusion as the reason for Schiaparelli’s mistake. This account followed Green’s earlier report of his observations in the prestigious Monthly Notices of the Royal Astronomical Society in 1877.
PEDRO AUGUSTO PORTO, PORTUGAL
Although Scoles’s history of the search for extraterrestrial life is interesting, I believe she missed the most important reason for believing such life exists. It is one that is difficult for us mere humans to comprehend: infinity. If the universe is infinite, then there must be many other planets with life on them. The problem is that the laws of physics say we are all bound by the speed limit of the speed of light. This means that life exists on many worlds, in many galaxies, but it and we will never be able to find each other. Let’s keep searching anyway; the pursuit of knowledge is unquenchable!
WES MOFFETT VIA E-MAIL
ANATOMICAL CONNECTIONS
Scientists themselves might benefit from reading Scientific American! In the July/August 2025 issue, there are two Advances articles reporting on findings that could be linked with those noted in previous issues.
“Wandering Mind,” by Nora Bradford [Advances; July/August 2025], concerns scientists studying how participants learn hidden patterns in tasks better when they let their mind wander. The researchers might consult “Speed Limit,” by Rachel Nuwer [Advances; March 2025], and note the described findings that the focused mind processes at about 10 bits per second, whereas the sensory systems do so at about a billion bits per second. This supports Queen’s University psychology researcher Jonathan Smallwood’s supposition in Bradford’s article that it’s the “particular state” in which mind wandering occurs, rather than the mind wandering itself, that causes people to learn such patterns: the lack of focus allows the body, working with those billion bits per second, to figure out the problem. I have experienced this myself for decades: when faced with any repetitive physical task, I immediately step back from thinking and let my body work out a process.
“Screaming Skin,” by Allison Parshall [Advances; July/August 2025], describes how Sun-Min Yu of the University of Massachusetts Amherst and her team found that epithelial cells make a signal when they are damaged that “may summon other cells to help rebuild the damaged spots.” Yu’s team might consult Martin Picard’s June 2025 article “The Social Lives of Mitochondria.” Picard shows how mitochondria, found in every cell of the body, communicate with one another, especially when they are in need of assistance. They do so between cells and by influencing multiple subsystems within each cell.
M. FOSQUE HILLSBOROUGH, N.C.
SLIME THAT HEALS?
In “Slime Attack” [Advances; July/August 2025], Elizabeth Anne Brown describes research on velvet worm slime, which can harden in seconds.
As someone who is taking various cardiovascular medications that result in thinned blood and profuse bleeding with the slightest scratch or scrape, I wonder whether this slime or similar substances might have application to staunch bleeding from a wound. (Besides people like me, it would be helpful for those with hemophilia.) The almost instant hardening might quickly form a barrier over the wound. And as noted in the article, the substance returns to a liquid state when soaked with water, so it could easily be washed off later.
GARY McKOWN WEST CHESTER, PA.
ICY APPRAISAL
In “Refreezing the Arctic” [June 2025], Alec Luhn reports on researchers who are trying to rebuild sea ice above the Arctic Circle to reflect the sun’s radiation and thus slow climate change. I hope you follow up by covering other means of Arctic ice-sheet restoration.
I am particularly interested in snow production because it seems to have several advantages over ice. For one, in addition to being more reflective than ice, snow is far superior as insulation, as Luhn notes. Thus, a layer of snow would keep the ice sheet colder than a layer of ice of the same mass—and for longer. Further, snow production would allow for much larger areas of coverage per pump station, reducing hardware costs.
NOEL KURTZ VIA E-MAIL
CLARIFICATION
“Closing In on a Cure,” by Tara Haelle [Innovations In Type 1 Diabetes; November 2025], noted Vertex Pharmaceuticals’ in-development drug Zimislecel. Breakthrough T1D did not fund trials for this drug. See more about its mechanism of action, intended recipients and trial results at www.scientificamerican.com/article/a-cure-for-type-1-diabetes-may-be-closer-than-you-think
ERRATA
“Bass Backlash,” by Martin J. Kernan [Advances; November 2025], should have clarified that the historical proliferation of smallmouth bass in Little Moose Lake resulted in native trout reaching only nine inches long at the time rather than to this day.
“Meteorite Heist,” by Dan Vergano [November 2025], should have said that, according to Nicholas Gessler, the Eli Ali object is being offered for sale in pieces at $200 a kilogram.
In “Organized Chaos,” by Aimee Lucido [Science Crossword; November 2025], the question for 16-Across should have specified a drum kit component.
