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“Ancient DNA caused a revolution in how we think about human evolution,” said Steven Churchill, co-author of the study and a professor of evolutionary anthropology at Duke University in a press release. “We often think of evolution as branches on a tree, and researchers have spent a lot of time trying to trace back the path that led to us, Homo sapiens. But we’re now beginning to understand that it isn’t a tree–it’s more like a series of streams that converge and diverge at multiple points....

If you’re a pessimist, therefore, you might conclude that the search for extraterrestrial life might well prove to be fruitless. If you need further ammunition to bolster your pessimism, you might take a look at the book Rare Earth, published by paleontologist Peter Ward and astronomer Don Brownlee in 2000. The authors advance a series of arguments to suggest that while life might well be common in the Milky Way, the sort of advanced life we’d really love to find is very rare....

Bass sound is also less directional than higher frequencies: That’s good in that it means the way that the subwoofer is pointing isn’t crucial, but it can result in sound waves bouncing all around the room. This can lead to dead spots (where waves cancel each other out) or boomy, exaggerated sounds where the bass is layered on top of each other. Bass frequencies are particularly sensitive to whatever else is in the room—furniture, pets, windows, walls—which is why getting your subwoofer in the right place in relation to your soundbar is so important....

Of particular concern are primates, which as a group are already among the most endangered species on the planet. Some monkeys, like the Yucatan spider monkey and the black howler monkey have been documented in studies as adapting to habitats that have been ravaged by cyclones in the past (over 90 percent of their known habitats have been affected at some point). The hope is that other primates will be able to do the same....

To find out, NASA’s MAVEN (Mars Atmosphere and Volatile Evolution mission) spacecraft is orbiting the red planet and studying the thin wisps of atmosphere that remain. MAVEN just got to Mars about a year ago, but the spacecraft is already teaching us a lot–enough to fill 49 scientific papers, in fact. Today, 4 MAVEN papers were released in Science, and the other 45 came out in Geophysical Research Letters. The latest data support the hypothesis that charged particles from the sun–especially those burped out during coronal mass ejections– helped to lay waste to Mars’ atmosphere long ago....

Right now, about a quarter of adults over 40 without any kind of cardiovascular disease are taking aspirin—some 29 million people. For those age 70 and over, the fraction taking it daily rises to half. That’s according to a recent study using 2017 data to look at just how many Americans are using aspirin in a way that’s no longer recommended. The new guidelines from the American College of Cardiology and the American Heart Association say no one over 70 should be taking daily baby aspirin unless they have a history of heart disease or stroke....

As Ida cruised through southern Appalachia, between Mississippi and Pennsylvania, it remained a tropical depression, leading to rainy days but not catastrophic flooding. Although it carried billions of tons of warm water from the Gulf, the moisture stayed mostly locked in its clouds. Most parts of Tennessee and Kentucky saw only an inch or two of rain. “The basic ingredients you need for heavy rainfall are moisture, instability, and lift,” says Dereka Carroll-Smith, a research meteorologist with the National Institute of Standards and Technology....

What is a Saildrone? The Saildrones are, as ocean-faring craft go, quite small: 23 feet long, 15 feet tall above the surface, and just 6 feet deep underneath it. To help other ships steer clear, Saildrones broadcast their location (and receive the location of other ships) from Automatic Identification System transceivers. Saildrones are also monitored remotely, allowing distant human operators to keep track of, and redirect, the drones as needed. The Red Sea is a long body of water, stretching over 1,200 miles from the Bab al-Mandab Strait to the mouths of the Gulf of Aqaba and the Gulf of Suez....

If you have a toddler, or if you encountered one in the last year, you’ve almost certainly experienced the “Baby Shark” song. Somehow, every kid seems to know this song, but scientists actually know very little about where and when sharks give birth. The origins of these famous baby sharks are still largely a mystery. Many of the large iconic shark species—like great whites, hammerheads, blue sharks and tiger sharks—cross hundreds or thousands of miles of ocean every year....

Sadly, it’s not likely we’re going to see rooftop wind power become a vibrant renewable energy source anytime soon. That’s simply because it wouldn’t work very well. Matthew Lackner, a professor of mechanical and industrial engineering at the University of Massachusetts, Amherst, tells Popular Science that wind doesn’t scale down as well as solar. “If you look at large-scale solar farms versus household solar, the cost per unit of energy produced will be lower for the large-scale solar farm just because of the economics of scale....

So why buy the cow when you’re already getting the milk for free? That’s a particularly important question now that YouTube’s premium content initiative, YouTube Originals, has fizzled out. But if you’re the kind of person who gets sucked into a YouTube vortex more than once a week, there are compelling reasons for you to invest $12 a month. No ads, ever It’s easy enough to avoid YouTube’s ads—those that can be skipped and closed, anyway—and considering you get free access to more videos than it’s humanly possible to watch in a lifetime, sitting through a few ads seems like a decent trade-off....

The challenging part is managing the logistics of the kayak when you’re not using it. Do you own a car and roof rack that can transport it? Are you physically able to lift it on top of your vehicle? Can you throw it in a garage for storage? A company called Oru Kayak aims to solve these problems with a boat that literally folds into a box—the boat actually becomes the box—for storage and transportation....

Maybe—but only if you’re drinking several gallons of seltzer a day. Here’s the chemistry that has soda drinkers worried: As carbon dioxide hits the water in your blood, it turns into carbonic acid. Too much acid in the blood can lead to a condition called acidosis, which could intercept small amounts of calcium from food as it makes its way to your bones, or steal it from them directly. Your greater concern, though, says endocrinologist Robert Heaney of Creighton University, should be the vomiting, headaches and impaired organ function that result from extreme acidosis....

To create the exhibit “Under Tomorrows Sky” (yes, it’s apostrophe-free), speculative architect Liam Young brought together a batch of like-minded folks to imagine a city of the future. The contributors include futurist and sci-fi writer Bruce Sterling, graphic novelist Warren Ellis, scientist Rachel Armstrong, and a lot more. Somehow that vision ends up resembling a collision between nature and urban blight; think of it as a sort of post-apocalyptic Walden Pond....

Recent research from the US Geological Survey (USGS) suggests that droughts, particularly the prolonged kind happening in parts of the US, could increase the risk of harmful arsenic exposure for people that rely on well water. Hundreds of millions of years ago, the baseline quality of your drinking water may have been set in stone, literally. Arsenic is a common groundwater contaminant, largely because of local geology. In Maine, for instance, the formation of the Appalachian Mountains and volcanic activity came together to concentrate arsenic and other metals into cracks inside the bedrock, explains Sarah Hall, a geologist at College of the Atlantic in Bar Harbor....

When scientists envision habitable alien worlds, they imagine these places as having Earth-like atmospheres dominated by nitrogen or carbon dioxide like those found on Mars and Venus. Recently, though, researchers have begun to suspect that planets with other types of environments might also be able to support life. In particular, some scientists have zeroed in on hydrogen-rich atmospheres. “Hydrogen-rich environments on Earth are incredibly rare and not well known,” Sara Seager, an astrophysicist and coauthor of the new research, told Popular Science in an email....

To upgrade the recliner, he removed the electric motor he had installed, the motor’s controller, a pair of batteries, and other parts. He bought a nine-horsepower, four-stroke dirt-bike engine, which fit perfectly in the space beneath the seat, and welded on a fixed rear axle so the engine could power both rear wheels instead of just one, as the electric motor had. Bike engines need to be kick-started, but the recliner’s lever snapped when he tried to use it....

The bag doesn’t include a ton of specified pockets or features you don’t really need, but does have the necessary places to attach items like a water bottle or a multi-tool. Four main pockets adorn the bag’s exterior—two on the sides, one larger compartment on the front, and then a zippered pocket in back. When you open the top zipper, you’ll find a laptop compartment with space on the front and the back to put other items....

And then there was another option: I could go seed-gathering myself. This would not only save time and money, but I would also be planting native species. This means helping promote clean water, healthy soil, pollinator habitats, and solid shorelines while helping prevent mass extinctions and climate change. The best part is that you can probably find these plants around your neighborhood, and once you gather a season’s worth, you can collect their seeds ad infinitum....

YouTube’s decision is the latest turn in an already surreal and disconcerting escalation of events reportedly stemming from a video posted earlier this month by The Dawn Project founder and U.S. Senate candidate, Dan O’Dowd. In O’Dowd’s upload, he calls the autopilot feature a “demonstrable danger to human life,” and illustrates his concerns via multiple clips of Teslas hitting child-sized pedestrian mannequins. Musk fans were subsequently so unhappy with the viral critiques that they quickly mounted a debunking campaign, showing off how confident they are in the feature by using their own children as potential victims....