Your letters and comments on the April 13, 2019 issue of Science News
Blast from the past
Ice core and tree ring data indicate that nearly 3,000 years ago, Earth was blasted with one of the strongest solar storms ever to pummel the planet, Carolyn Gramling reported in “One of the strongest known solar storms blasted Earth in 660 B.C.” (SN: 4/13/19, p. 15).
Reddit user diffcalculus wondered what kind of damage such a storm would cause today.
Earth hasn’t experienced a solar storm of that intensity in the modern era, so it’s hard to say. But solar storms weaker than the 660 B.C. event have been known to knock out power grids, satellites and radio communications, Gramling says. A solar storm in 1989 sent so much energy across North America that it shut down the power grid in Quebec, Canada.
Thanks to a fleet of satellites and spacecraft, the sun is under constant surveillance. If a potentially disruptive solar storm were heading this way, emergency officials would know and could prepare by switching off key components on satellites or switching on backup systems to protect power grids (SN Online: 4/9/12).
Scientists spotted the asteroid Bennu (shown below) ejecting plumes of dust, an activity never before seen on an asteroid, Lisa Grossman reported in “Surprising astronomers, Bennu spits plumes of dust into space” (SN: 4/13/19, p. 10). The story inspired online reader Doug to riff on an Elton John classic: “Bennu and the jets.”
Get a grip
A vacuum-driven robotic gripper can lift objects that weigh more than 120 times its own weight. The gripper can also gently handle fragile items like soft fruits and wine glasses, Maria Temming reported in “An origami design helps this robot lift delicate and heavy cargo” (SN: 4/13/19, p. 5).
Online reader Dahak wondered about the lightweight gripper’s durability.
As a general rule, durability is a major challenge when building a soft robot, Temming says. “There’s always a trade-off between sturdiness and pliability.” Although the gripper had a strong grasp, its soft rubber and latex skin developed holes and needed to be replaced after testing. The researchers also made a more durable version out of plastic and nylon. “But tests showed that robot had a poor grip and could not carry as heavy a load as the rubber and latex gripper,” Temming says. “The researchers plan to test different materials to optimize the gripper’s strength and durability. Adding things to the robot’s skin like anti-slip tape or gecko-inspired adhesives might improve grip, they say.”
A Peruvian spider is the fastest-known arachnid. It uses its web to fling itself at prey at a maximum acceleration of about 1,100 meters per second squared, Emily Conover reported in “This spider slingshots itself at extreme speeds to catch prey” (SN: 4/13/19, p. 5).
Readers on Twitter wondered how the spiders withstand accelerations 110 times that of Earth’s gravity.
“Unfortunately, we don’t have an answer for that yet,” says biophysicist Saad Bhamla of Georgia Tech in Atlanta. But the spiders’ smaller size relative to humans, as well as their simpler brain structure and blood pumping system, may make the arachnids more resilient to large g-forces, he suggests. Bhamla and colleagues are currently studying the spiders in more detail.
The feature “Can Silicon Valley entrepreneurs make crickets the next chicken?” (SN: 5/11/19 & 5/25/19, p. 28) incorrectly stated that discoid roaches thrash on their backs before releasing young in sacs. Females do not have to lie on their backs to give birth, and the young escape the sac before leaving the mother’s body. Also the quiet house crickets mentioned are juveniles. Adults of this species chirp during the day as well as at night.