A new type of laser can find and destroy cancerous melanoma cells in blood with 1,000 times the sensitivity of current detection tools. Most melanoma-related deaths occur because malignant cells at the original tumor site seep into the blood and spread to vital organs before doctors find them, Vladimir Zharov, director of the nanomedicine center at the University of Arkansas, told Live Science.

A machine called a Cytophone, described in the June 12 issue of Science Translational Medicine, shoots laser pulses at the outside of the skin. The laser heats the dark melanin pigment in the malignant cells, and an ultrasound sensor detects the tiny heat waves the cells emit.

Using the new technique, researchers identified circulating tumor cells in 27 of 28 cancer patients within 60 minutes with no false positives for other healthy volunteers, side effects, or skin damage. Scientists intended to find cancer cells but were surprised when they discovered the low-energy laser used for detection also destroyed those cells.

Melanoma, the most dangerous skin cancer, will kill an estimated 7,230 people this year.

Cell phone bone?

A researcher in Australia thinks the way we hold our heads while looking at smartphones is causing bony spikes to grow at the base of some individuals’ skulls. David Shahar, a health researcher affiliated with the University of the Sunshine Coast, recently told the BBC he believes the phenomenon, known as an external occipital protuberance, results from people—particularly those 18-30 years old—holding their heads at unnatural angles to look at smartphones. “I have been a clinician for 20 years, and only in the last decade, increasingly, I have been discovering that my patients have this growth on the skull,” he said.

In a 2016 study appearing in the Journal of Anatomy, Shahar and another researcher found the skull spikes in 41 percent of the 218 young adults they studied. One man’s growth was 1.4 inches long. Shahar said the bone growths, possibly a response to strain from the neck muscles, rarely cause medical problems. —J.B.

Muncher of minerals

A newly discovered species of shipworm, a clam-like creature known for boring into wooden ship hulls, has a surprising appetite for rock. All other known shipworms eat wood and live in saltwater, but this species inhabits freshwater, Live Science reported. Wood-eating shipworms, discovered in the fourth century B.C., cause billions of dollars of damage to piers, ships, and fishing equipment every year. A team of researchers found the rock-eating species boring into a limestone cliff along the Abatan River in the Philippines.

The Philippine shipworms, typically about 4 inches long, resemble chunky, translucent worms and create burrows that provide habitat for other species in the river, such as crabs, snails, and fish. Reuben Shipway, a marine biologist who helped study the creatures, told Live Science the voracious mollusks are chomping their way through so much rock they “are literally changing the course of the river.” Shipway and his colleagues described the species June 19 in the Proceedings of the Royal Society B.

The shipworms munch on limestone using shovel-like projections on their shells and expel the rock as fine sand. Birds and other animals use stones to aid digestion, but Shipway says the new species is the only known animal that eats rock by burrowing into it. —J.B.