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By 2100, Greenland will be shedding ice faster than at any time in the past 12,000 years , scientists report October 1 in Nature . Since the 1990s, Greenland has shed its ice at an increasing rate ( SN: 8/2/19 ). Meltwater from the island’s ice sheet now contributes about 0.7 millimeters per year to global sea level rise ( SN: 9/25/19 ). But how does this rapid loss stack up against the ice sheet’s recent history, including during a 3,000-year-long warm period? Glacial geologist Jason Briner of the University at Buffalo in New York and colleagues created a master timeline of ice sheet changes spanning nearly 12,000 years, from the dawn of the Holocene Epoch 11,700 years ago and projected out to 2100. The researchers combined climate and ice physics simulations with observations of the extent of past ice sheets, marked by moraines. Those rocky deposits denote the edges of ancient, bulldozing glaciers. New fine-tuned climate simulations that include spatial variations in temperature

In the midst of a pandemic that has brought so much worry and loss, it’s natural to want to help — to do some small part to solve a problem, to counter pain, or to, importantly, remind others that there is beauty and wonder in the world. Scientists have long been doing just that. Many are chasing answers to the myriad challenges that people face every day, and revealing the rewards in the pursuit of knowledge itself. It’s in that spirit that we present this year’s SN 10: Scientists to Watch. For the sixth consecutive year , Science News is featuring 10 early- and mid-career scientists who are pushing the boundaries of scientific inquiry. Some of the researchers are asking questions with huge societal importance: How do we prevent teen suicide ? What are the ingredients in wildfire smoke that are damaging to health? Is there a better way to monitor earthquakes to save lives ? What about finding new ways to diagnose and treat diseases ? Others are trying to grasp how weird and wonder

The Milky Way’s core harbors two giants: the galaxy’s largest black hole and a cluster of tens of millions of stars around the black hole that is denser and more massive than any other star cluster in the galaxy. Most of the cluster’s many stars shine within just 20 light-years of the galactic center and all together weigh about 25 million times as much as the sun. New observations suggest that this “nuclear star cluster” owes some of its brilliance to another big group of stars, or even a small galaxy, that the main cluster swallowed. Nuclear star clusters exist in many galaxies and are the densest star clusters in the universe. Astronomers are trying to figure out how these gatherings get so jam-packed and how they feed the giant black holes at the centers of galaxies. To get a look at the Milky Way’s core, Tuan Do, an astronomer at UCLA, and colleagues observed about 700 red giant stars within five light-years of the galaxy’s heart. Because dust between Earth and the galactic cen

What could be more 2020 than an ongoing invasion of jumping worms? These earthworms are wriggling their way across the United States, voraciously devouring protective forest leaf litter and leaving behind bare, denuded soil. They displace other earthworms, centipedes, salamanders and ground-nesting birds, and disrupt forest food chains. They can invade more than five hectares in a single year, changing soil chemistry and microbial communities as they go, new research shows . And they don’t even need mates to reproduce. Endemic to Japan and the Korean Peninsula, three invasive species of these worms — Amynthas agrestis, A. tokioensis and Metaphire hilgendorfi — have been in the United States for over a century. But just in the past 15 years, they’ve begun to spread widely ( SNS: 10/7/16 ). Collectively known as Asian jumping worms, crazy worms, snake worms or Alabama jumpers, they’ve become well established across the South and Mid-Atlantic and have reached parts of the Northeast,

Clues from a chemical —   Science News , October 3, 1970 An experimental drug’s effects on the sexual behavior of certain animals is arousing interest among investigators.… The drug, para-chlorophenylalanine … reduces the level of a naturally occurring neurochemical, serotonin, in the brain of rats, mice and dogs.… Little is known about how serotonin acts in the brain, and investigators quickly recognized that PCPA could be used to study this brain chemical. Update PCPA helped e­stablish serotonin’s role in regulating sexual desire, as well as sleep, appetite and mood. The chemical messenger has become key to one common class of antidepressant drugs called selective serotonin r­euptake inhibitors. Identified in 1974, SSRIs work by increasing the brain’s serotonin levels. But such drugs can hinder sexual desire . One SSRI that failed to relieve depression in humans found a second life as a treatment for sexual dysfunction. Approved by the U.S. Food and Drug Administration in 201

Fresh intel from Mars is sure to stir debate about whether liquid water lurks beneath the planet’s polar ice. New data from a probe orbiting Mars appear to bolster a claim from 2018 that a lake sits roughly 1.5 kilometers beneath ice near the south pole ( SN: 8/18/18 ). An analysis of the additional data, by some of the same researchers who reported the lake’s discovery, also hint at several more pools encircling the main reservoir , a study released online September 28 in Nature Astronomy claims. If it exists, the central lake spans roughly 600 square kilometers. To keep from freezing, the water would have to be extremely salty, possibly making it similar to subglacial lakes in Antarctica. “This area is the closest thing to ‘habitable’ on Mars that has been found so far,” says Roberto Orosei, a planetary scientist at the National Institute for Astrophysics in Bologna, Italy, who also led the 2018 report. Ali Bramson, a planetary scientist at Purdue University in West Lafayette, I

Schrödinger’s Web Jonathan P. Dowling CRC Press, $40.95 When news broke last year that Google’s quantum computer Sycamore had performed a calculation faster than the fastest supercomputers could ( SN: 12/16/19 ), it was the first time many people had ever heard of a quantum computer. Quantum computers, which harness the strange probabilities of quantum mechanics, may prove revolutionary. They have the potential to achieve an exponential speedup over their classical counterparts, at least when it comes to solving some problems. But for now, these computers are still in their infancy, useful for only a few applications, just as the first digital computers were in the 1940s. So isn’t a book about the communications network that will link quantum computers — the quantum internet — more than a little ahead of itself? Surprisingly, no. As theoretical physicist Jonathan Dowling makes clear in Schrödinger’s Web , early versions of the quantum internet are here already — for example,

Supercooled water may be a two-for-one deal. A long-standing theory holds that liquid water at temperatures well below freezing is composed of two different arrangements of molecules, one with high density and one with low density. Now, an experiment provides new evidence for that theory , researchers report in the Sept. 18 Science . Typically, water freezes below 0° Celsius thanks to impurities, such as dust in the water, on which ice crystals can nucleate. But pure water, which lacks those crystallization kick starters, can remain liquid to much lower temperatures, a phenomenon called supercooling. In the 1990s, a group of physicists proposed that, at high pressures and very low temperatures, supercooled water splits into two distinct liquids of different densities. At atmospheric pressure, under which the new experiment took place, supercooled water would retain some traces of that behavior, resulting in small-scale, transient arrangements of molecules in high-density and low-den

COVID-19 kills some people and leaves others relatively unscathed. But why? Age and underlying health conditions are risk factors, but scientists are trying to tease out other differences, including in people’s genes or immune systems, that may play a role. Two new studies show that flaws in the body’s early response to viral infection, one caused by genetic defects and one by traitorous immune responses, are behind some severe COVID-19 cases. In one study, published online September 24 in Science, researchers identified certain genetic defects in some people with severe COVID-19 that make the body produce fewer interferons, proteins that are part of the immune system’s early warning system. In other people with severe disease, however, the body’s own immune responses disable interferons, a second study published online in Science the same day finds. These defects mean that the coronavirus that causes COVID-19, SARS-CoV-2, can infect cells without raising red flags, evading the

A two-month stint on the moon would expose astronauts to roughly the same amount of radiation as they would get living on the International Space Station for five months, according to new measurements from the lunar surface. Detectors on China’s lunar lander Chang’e-4 measured radiation from galactic cosmic rays at the moon’s surface in 2019, from January 3 to 12 — just after landing on the farside of the moon — and again from January 31 to February 10. An astronaut would be exposed to an average daily dose of 1,369 microsieverts of radiation, researchers report online September 25 in Science Advances . That’s about 2.6 times as high as the average daily radiation exposure of 523 microsieverts recorded inside the ISS, the scientists say. Being on the moon “for two months would be OK. That is about the same amount of radiation astronauts receive at the ISS [over five months] and wouldn’t be incredibly dangerous,” says coauthor Robert Wimmer-Schweingruber, a physicist at Christian Alb