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July 16, 2025—Dammed water is shifting Earth's poles, injured skin cells scream, and why the universe is filled with matter.
—Andrea Gawrylewski, Chief Newsletter Editor | | A view of HOPS-315. ALMA(ESO/NAOJ/NRAO)/M. McClure et al. (CC BY 4.0) | | | | |
Star trails above the Three Gorges Dam in Yichang, Hubei province, China. Large dams like this one are shifting the Earth's poles away from its axis of rotation. Cynthia Lee/Alamy Stock Photo | | The hundreds of billions of gallons of water trapped behind dams have pushed Earth's poles away from the planet's axis of rotation, the axis around which Earth rotates. This deviation is known as true polar wander. To estimate the contribution of dammed water to polar wander, scientists reviewed almost 7,000 dams constructed from 1835 to about 2011, and calculated their effect on Earth's poles. By 2011, the North pole was only 20.5 centimeters away from its starting location, but in that time, it had moved back and forth over a total of 113.4 cm, a little more than a meter. How it works: As Earth rotates, the surface moves to redistribute mass and stabilize the planet's spin. Imagine Earth as a beach ball spinning on someone's finger. If someone stuck a wad of gum on the ball, the ball might wobble on its axis of rotation and move to adjust to the increase in mass, explains Jim Davis, a geodesist at Columbia University. On Earth, instead of a wad of gum, shifting ice sheets and movements of mantle rock cause the planet to adjust itself. Though dams move a smaller amount of mass than these other phenomena, they still have an appreciable effect. What the experts say: "The mass motions reveal both important natural processes in the Earth system, as well as significant human-induced changes, so understanding them is important for science and society, including climate change and solutions to climate change." For example, many tools and devices like GPS rely on high-precision measurements that might be affected by a shift in Earth's poles, he says. — Andrea Tamayo, newsletter writer | | Some cells talk to each other using electricity; neurons and heart muscle cells release electrical pulses to quickly send information and make the heart beat. For a long time, scientists thought skin cells were silent. But a new study has found that when wounded, skin cells "scream;" they emit a slow electric pulse that resembles a firing neuron. Researchers cultured epithelial cells from humans, and kidney cells from dogs in dishes fitted with electrodes and then used a laser to damage the cells. In response, the cells emitted bursts of electrical "noise" that lasted a few seconds each. Why this is interesting: Using electrical signaling means the skin cells might be able to communicate over longer ranges to trigger healing, says Ellen Foxman, a researcher at Yale School of Medicine. Understanding this communication could reveal why the healing process sometimes goes wrong, such as in scarring, she says. "That's what I'm excited about," says Foxman. "Whenever you find a new pathway, you could study and potentially use [it] to develop a new treatment."
What the scientists say: It's still not certain what role this signaling plays in living organisms or what other cells do when they receive a signal from the skin cells, says Sarah Najjar, who studies gut epithelial cells at New York University. She wonders what happens downstream of this activity and if it influences neurons. —Andrea Tamayo, newsletter writer
| | - Quantum sensing of Earth's magnetic field could replace GPS in aircraft navigation. | Wall Street Journal
- A physicist and an audio engineer try to identify a mysterious strange noise that rattled an Oregon town in 2016. | Atlas Obscura
- Is the fabric of spacetime made of memory cells? | New Scientist
| | The world's dams provide reliable drinking water, agricultural irrigation, flood control and electricity. They also dramatically transform rivers upstream and downstream, displacing residents, disrupting animal migrations and populations, flooding thousands of trees and plants, and disrupting the flow of nutrients and sediments in the flow of water. In recent decades, dam removal has picked up, helping to restore the populations of vital species and habitats. They are feats of engineering, yes, but dams come at a great cost. | | —Andrea Gawrylewski, Chief Newsletter Editor | | | | |
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