A new study shows that Tangier Island could be lost to rising sea levels sooner than previously realized, Trishla Ostwal reported in “Time is running out to save Virginia’s Tangier Island” (SN: 1/15/22, p. 4).
Reader John T. Hanou wondered if groundwater extraction near the island is contributing to its plight.
It’s true that groundwater pumping can significantly affect the rate at which land sinks in the southern Chesapeake Bay region. But its impact is smaller on Tangier Island, which is far from any major groundwater pumping source, say the study’s coauthors, marine biologist David Schulte of the U.S. Army Corps of Engineers and his son Zehao Wu, a student researcher at Biogenic Solutions Consulting in Newport News, Va. Data from the U.S. Geological Survey suggest that groundwater extraction is responsible for about 20 percent of the sea level rise around the island, the duo say. The majority “is due to human-accelerated climate change.”
Researchers contend that the ancient Clovis people of North America used stone points to butcher scavenged mammoths rather than hunt the giant beasts, Bruce Bower reported in “Pointed takedown of the mammoth hunters” (SN: 1/15/22, p. 22).
Several readers asked if methods such as coating stone points in poison or driving mammoths into pits would have allowed the Clovis people to hunt the animals.
Evidence of such methods has never been discovered, says archaeologist Metin Eren of Kent State University in Ohio. The Clovis people could have occasionally hunted mammoths, he says, possibly by wounding and tracking the beasts until they died. But these people likely did not hunt mammoths regularly and successfully, he contends.
Dust it off
NASA’s Ingenuity helicopter is still helping the Perseverance rover do science, Lisa Grossman reported in “Ingenuity’s Mars flight plan extended” (SN: 1/15/22, p. 12).
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Reader Sherry Kadrmas wondered if Ingenuity could help give other rovers and landers on Mars a power boost by removing dust from their solar panels.
Using Ingenuity to dust off rovers is probably impractical, says Michael Mischna, an atmospheric scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. First and foremost, dusty solar panels aren’t a major concern because they haven’t significantly hindered solar-powered rovers from doing science, he says. Second, Martian dust is extremely fine, similar to talcum powder. Gravity and electrostatic forces “stick” the fine dust to spacecraft surfaces. Winds stronger than what Ingenuity could produce might not even effectively clear the dust, Mischna says. What’s more, the helicopter could collide accidentally with a rover while clearing dust, damaging both.
Most importantly, Ingenuity would “never be able to travel the distance” to other space probes on Mars, Mischna says. The nearest active solar-powered mission, called InSight, is about 3,500 kilometers away from the helicopter. To date, Ingenuity has traveled about 3.5 kilometers, he says. The helicopter can’t wander far from Perseverance because it relies on the rover for instructions from scientists on Earth.
“Mental gymnastics” (SN: 1/29/22, p. 24) mischaracterized Tommy Minkler’s specialty. He is a mindfulness researcher and sports psychology graduate student.