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Astronomers have caught two big ancient galaxies in the act of colliding, shedding new light on the role such megamergers played in galactic evolution during the universe’s youth. The colossal smashup will eventually produce one giant elliptical galaxy, researchers said, suggesting that most such behemoths formed rapidly in this manner long ago, rather than growing slowly over time by gobbling up a series of relatively small galaxies. “I think at least 90 percent of elliptical galaxies at this mass were formed through this channel,” study lead author Hai Fu, of the University of California, Irvine, told SPACE....

FLIGHT OF THE NAVIGATORS “The Quantum Nature of Bird Migration,” by Peter J. Hore and Henrik Mouritsen, describes the biophysical underpinnings of how the animals navigate. This article is fascinating. I believe that Earth’s magnetic north pole shifts position every so often. How would this affect the ability of birds to migrate successfully? STEVEN SVERDLIK Dallas, Tex. Radio-frequency (RF) transmitters are increasingly attached to birds to track their movements. The sizes of transmitters and the methods of attaching them have had unfortunate physical impacts on birds, which are gradually being addressed through design improvements....

The most recent reports from the Intergovernmental Panel on Climate Change experts have made two things clear: One, any hope of avoiding catastrophic climate change requires dramatically reducing the use of fossil fuels. And two, doing this is a political challenge, not a scientific one. Technologies that can reduce emissions exist now; what is absent is the political will to do so. The deep political opposition to reducing fossil-fuel reliance is the direct result of decades of efforts by the fuel industry to sow climate denial, feed misinformation to the public, influence elected officials and “greenwash” its efforts....

A new discovery about the function of neurons could help scientists understand how the brain assembles information during learning and memory formation. Scientists have found that when electrical impulses are passed from one neuron to another, they not only strengthen the synapse (connection) between them, but they also give a boost to neighboring synapses, priming them to learn more quickly and easily. Researchers report in Nature that the extra kick, which lasts from five to 10 minutes, may be key to memory formation....

Key concepts Light Energy Heat Colors Absorption Reflectivity Introduction Have you ever wondered if changing the color of your house does anything other than alter its appearance? Could it also be doing something as practical as influencing how much money is spent on energy bills? On hot summer days, people consume a lot of energy to keep their houses cool. If less energy could be used to do this, not only would it save people money, it might also help the environment by decreasing the amount of energy we use!...

South Africa is losing its battle against biological invaders, according to the first attempt by the government to comprehensively assess the status of the country’s alien species. The invaders, including forest-munching wasps, hardy North American bass and trees attractive to mosquitoes, cost the country approximately 6.5 billion rand (US$450 million) a year and are responsible for about a quarter of its biodiversity loss. That’s the conclusion of a pioneering report that the South African National Biodiversity Institute in Pretoria released on 2 November....

As the congestion has grown, so too have close calls between orbiting assets. The International Space Station, for instance, regularly tweaks its orbit to avoid potentially hazardous debris. Worse yet, there has been an uptick in the threat of full-on collisions that generate menacing refuse that exacerbates the already bad situation. Consider the February 2009 run-in between a dead Russian Cosmos satellite and a commercial Iridium spacecraft, which produced an enormous amount of debris....

COVID-19 vaccine rollouts are finally upon us. They hope that herd immunity—protection from an infectious disease that occurs once a sufficient proportion of the population has been vaccinated or infected—is on the horizon. But even though the first vaccines to receive emergency use authorization from the U.S. Food and Drug Administration are exceptionally effective at preventing COVID-19, data cannot yet tell us if they hinder transmission of SARS-CoV-2, the virus that causes the disease....

What is Impostor Syndrome? Impostor Syndrome is a pervasive feeling of self-doubt, insecurity, or fraudulence despite often overwhelming evidence to the contrary. It strikes smart, successful individuals. It often rears its head after an especially notable accomplishment, like admission to a prestigious university, public acclaim, winning an award, or earning a promotion. Impostor Syndrome doesn’t discriminate: people of every demographic suffer from feeling like a fraud, though minorities and women are hardest-hit....

When he touched down in Maseru, Lesotho, in September 2007, Salmaan Keshavjee had to help get a hospital renovated and a lab built. But first, his colleague Hind Satti said that they must visit a patient nearly 40 miles (65 kilometers) away. The ride through the small and landlocked African nation that sits like an island inside South Africa dragged on for more than two hours over obliterated roads until Keshavjee and Satti reached a small mud home....

We’re now more than two decades out from the initial announcement of the National Nanotechnology Initiative (NNI), a federal program from President Bill Clinton founded in 2000 to support nanotechnology research and development in universities, government agencies and industry laboratories across the United States. It was a significant financial bet on a field that was better known among the general public for science fiction than scientific achievement. Today it’s clear that the NNI did more than influence the direction of research in the U....

Your eyes may be reading this, but you likely used your hands to get here. Every day your fingers, wrists and forearms conduct the symphony of motor movements that allow you to click a mouse, type on a keyboard or swipe a screen. But what if you lost your hand? What kind of machine could restore your abilities to grip, click, tap or touch? What Happened? In a new study, a group of researchers at the University of Utah have re-engineered a prosthetic system to let a man whose hand was amputated feel a wide range of sensations, helping him physically grasp a variety of delicate objects, from a glass of wine to a single grape....

Rainforest campaigners are concerned that a recent Food and Drug Administration proposal to phase out trans fats may boost demand for palm oil, a crop whose large-scale production is linked to deforestation in Southeast Asia. Trans fats, which include partially hydrogenated or hydrogenated oils, are chemically altered oils that give peanut butter its smooth texture, pastries their long shelf life and margarine its solid state. It is a chemically stable source of unsaturated fat, long valued for its ability to make foods last longer....

Purple rashes, swollen legs, clogged catheters and sudden death—blood clots, large and small, are a frequent complication of COVID-19, and researchers are just beginning to untangle why. For weeks, reports have poured in of the disease’s effects throughout the body, many of which are caused by clots. “This is like a storm of blood clots,” says Behnood Bikdeli, a fourth-year cardiology fellow at Columbia University in New York City. Anyone with a severe illness is at risk of developing clots, but hospitalized patients with COVID-19 appear to be more susceptible....

Excerpted with permission from A Naturalist Goes Fishing: Casting in Fragile Waters from the Gulf of Mexico to New Zealand’s South Island, by James McClintock. Available from St. Martin’s Press. Copyright © 2015. (Scientific American and St. Martin’s Press are part of Holtzbrinck Publishing Group.) “A veteran scientist and adventurer, Jim McClintock writes with passion and knowledge of his love of fishing within some of the most beautiful yet threatened waterways on Earth....

Some things are uniquely Martian. And dry ice hovercraft may be one of them. For 10 years, scientists have been trying to understand what causes “linear gullies” on Mars—long, thin canals carved into sandy slopes and crater walls. Flowing water doesn’t quite work as an explanation. Water should carry rocks and dirt downstream, dumping it in a fan-shaped apron at the bottom. But these gullies don’t have debris deposits. They abruptly stop....

After more than a year in orbit around a comet, the European Rosetta spacecraft and its icy dance partner are hitting a huge milestone: their closest approach to the sun. The Rosetta and its target, Comet 67P/Churyumov–Gerasimenko, reach perihelion today (Aug. 13), when the comet’s 6.5-year orbit brings it within 114.9 million miles (185 million kilometers) of the sun. Activity is already exploding on Comet 67P. In late July, Rosetta’s camera caught a jet eruptingin the space of less than half an hour....

At first, people infected with the Ebola virus appear to have the flu—fever, chills, muscle aches. Then the bleeding begins. As the virus hijacks cells throughout the body to make copies of itself, it overwhelms and damages the liver, lungs, spleen and blood vessels. Within days organs begin to fail and many patients fall into a coma. Some outbreaks, primarily in Central and West Africa, have killed up to 90 percent of infected individuals....

TEMPE, Arizona—Based on our capacity for thought, social learning and cooperation, humans often hold our own species in high regard compared to all other living things. It is certainly true that the human species is a statistical outlier along several dimensions, so scientists have recently been working out a sequence of the anatomical and behavioral adaptations that were necessary across evolutionary time for our ancestors to become fully human. Emboldened by such developments, 25 experts from a range of disciplines gathered February 19-22 at a workshop, “Origins of Human Uniqueness and Behavioral Modernity,” organized by Arizona State University’s Origins Project to identify the suite of traits that could be used to mark the starting point of humankind....

Whether we are pinching the cheeks of an adorable toddler or enveloping a beloved pet in a bear hug, most of us have experienced the strange drive to give something cute a gigantic squeeze. New research by two Yale University psychologists details how the sight of something cute brings out our aggressive side. Rebecca Dyer and Oriana Aragon investigated “cute aggression” by showing study participants slide shows of either cute, funny or normal animal photographs....