TIME Research

Humans and Neanderthals Were Actually Neighbors

Paleontologists know plenty about our nearest human cousins, the Neanderthals. They know that this highly successful species walked the Earth for some 300,000 years (we’ve been around for less than 200,000). They know the Neanderthals kept their caves surprisingly tidy; that they ate things other than raw meat; that they practiced recycling, wore jewelry and were generally much more sophisticated than their popular reputation would suggest.

Yet it didn’t take long after our own species invaded their last known outpost in Europe that the Neanderthals went utterly extinct. Now a new paper in Nature suggests it happened over a period of between 2,600 and 5,400 years or so—which is twice as fast as anyone had thought. The two groups did, evidently, coexist: “They lived in Europe at the same time,” says lead author Tom Higham, of Oxford, “although they were spatially separated. It was like a mosaic.” Agrees William Davies, of the University of Southampton, who wrote a commentary on the new research, also in Nature, “It’s not a neat story. It’s quite complex.”

The key to the new analysis was an unusually large sample of human and Neanderthal remains from 40 different sites across Europe, along with improved methods for filtering out contaminants from the samples before attempting to date them. In many cases, the remains weren’t bones but rather stone tools thought to characteristic of one species or the other—so-called Mousterian and Châtelperronian tools for the Neanderthals and Uluzzian tools for our own ancestors.

That raises, if not a red flag, then at least a sort of pinkish one, according to Davies. “In the old days, we had very few assemblages of tools, so it was quite easy to say that Mousterian tools represented Neanderthals, while tools with longer blades reflect anatomically modern humans.” But with more and more tools in their collections, paleontologists have become less sure. “The whole thing has become more blurred and less certain.”

The new analysis doesn’t depend entirely on who made what tools, however, and, says Davies, “the areas they’ve chosen to analyze are places where we can be more confident than most.” What makes the work so potentially important, he says, is that it gives a much finer-grained picture than ever before of where Neanderthals and modern humans lived and when, and how those patterns changed as Neanderthal numbers dwindled, then vanished.

That in turn will help anthropologists figure out how the Neanderthals vanished—what force or forces drove them extinct by about 40,000 years ago. “We think the Neanderthals had very low population numbers when modern humans arrived,” says Higham, perhaps in part because Europe was in the throes of an Ice Age at the time, so they were struggling against harsh conditions that couldn’t support large numbers of individuals. Modern humans, Higham observes, had been living in Africa, which was much more benign. “Modern humans also seemed to have more modern technology,” he says, “which wouldn’t have been a huge advantage, but over the long duration might have given them an edge.”

Scientists also know that Neanderthals and modern humans interbred at some level, which is why about 2% of our genes, on average, are Neanderthal in origin. The details of those interactions are still completely unknown—for now, anyway. “For me,” says Davies, “the big achievement here is that we now have a way of getting much more information out of both skeletal and archaeological remains. We can look at the molecular level on genetic inheritance, movement patterns, even what they were eating.”

The mystery of when and where the Neanderthals made their last stand may be just about wrapped up. And the answer to why they disappeared might not be a mystery for much longer.

 

TIME weather

Flash Floods and Stranded Drivers in Arizona After Heavy Rain

Fast and furious rainfall in the Phoenix area damaged houses, stranded drivers and forced at least one airborne rescue, which was broadcast live on television Tuesday. The Associated Press reported nearly 3,000 homes were left without power by the storm, which dumped up to two inches of rain in the span of an hour, in a state unused to so much precipitation

TIME Chemistry

Octopus Skin Has Inspired a New Type of Camouflage Sheet

It can only switch from black to transparent and back again, but that's a start

Scientists have developed a color-changing device inspired by octopuses and their natural camouflaging techniques.

The research, carried out at the University of Houston and University of Illinois at Urbana–Champaign, looked at how the skins of octopuses, squid and cuttlefish can change color so rapidly. From there, researchers were able to design a heat-sensitive sheet that quickly changes color when detecting light.

At room temperature the flexible sheet is black. Once the device’s top layer, which contains a heat-sensitive dye, detects light it becomes transparent. True, this is hardly a rainbow of hues, but scientists believe it is the first step to developing a camouflage material for human use.

“[The device] is by no means a deployable camouflage system but it’s a pretty good starting point,” said a lead researcher, John Rogers of the University of Illinois at Urbana–Champaign, to National Geographic.

Popular Mechanics broke down the layers of the new device as follows:

The top layer of the new device is loaded with a temperature-sensitive dye that appears black at low temperatures and clear at temps above 116 degrees F. This dye-filled layer sits on top of a layer of white reflective silver tiles, an ultra-thin layer of silicon circuits that control the dye’s temperature, and a transparent silicone rubber foundation. All together, this stack measures less than 200 microns thick. (The average human hair is 100 microns wide.)

Underneath this flexible sandwich is a base layer containing an array of light-sensing photodetectors. The corners of each dye-filled pixel and silver tile above this photoreceptor layer are notched, creating gaps that are like holes in a mask, allowing light to get through to the photoreceptors so they know how and when to change color. This adaptive camouflage system can respond to changing patterns of illumination within just one to two seconds.

[National Geographic]

TIME medicine

These Mummified Cadavers Helped Teach Medical Students in the 1800s

The Burns Collection consists of human cadavers from the early 1800s that were anatomically dissected and preserved to teach anatomy and surgery to medical students. For the first time this portion of the collection is on display to the public as a part of traveling exhibit "Mummies of the World: The Exhibition."

TIME astronomy

Black Holes? I’ll Take a Medium, Please

HEIC0604A.JPG
A mosaic image of the starburst galaxy Messier 82. NASA-ESA/AP

Scientists may have identified an intermediate-sized black hole for the very first time

In one sense, black holes are just ridiculously exotic. Their surface gravity is so powerful that even something as fast as light can’t escape (that’s why they’re black). And what’s actually inside a black hole isn’t just strange: it’s literally indescribable by any known law of physics.

But while they’re among the strangest things in the universe, they aren’t especially uncommon. Astronomers now know that black holes with the mass of millions or even billions of stars lurk at the cores of most galaxies, including the Milky Way, while much smaller black holes, containing just a few tens of stars’ worth of matter, are scattered all over the known universe.

In theory, there’s no reason intermediate-size black holes shouldn’t exist as well, with masses of a few hundred or a few thousand stars. But so far, despite some tantalizing hints, nobody has definitively found one. That may just have changed, however: a new report in Nature has flagged just such an object in the nearby galaxy Messier 82, which lies about 12 million light-years from Earth in the direction of the Big Dipper.

The black hole in question weighs about 400 times as much as the Sun, and is “just amazing” in the words of co-discoverer Richard Mushotzky, of the University of Maryland. That’s true for several reasons; the first is that this object, known as M82 X-1, has been known about for years because it shines brightly in the X-ray part of the electromagnetic spectrum. That marked it from the start as a candidate black hole, since these voracious cosmic vacuum cleaners suck in gas at such a prodigious rate that the infalling matter heats to the kinds of temperatures that generate X-rays.

Astronomers also knew from the brightness of those rays that M82 X-1 was most plausibly a black hole of intermediate mass–somewhere above 100 but less than a thousand solar masses. The problem: while astronomers know how a small black hole forms (it’s created when a massive star dies in a supernova explosion), it’s not clear how a black hole of more than 50 or so solar masses comes to be.

That put a premium on making sure they truly had the mass right, and lead author Dheeraj Pasham, a Maryland grad student, used a novel technique to figure out what that mass must be. Astronomers have noted that the X-rays from small black holes in the Milky Way pulsate with a characteristic rhythm that is a consequence of general relativity. “It’s kind of complicated,” Mushotzky says. “You don’t really want to know.”

The rate of the pulsations depends on the mass of the black hole, and by carefully analyzing observations from NASA’s Rossi X-Ray Timing Explorer satellite, Pasham was able to do that calculation with unprecedented precision. “It took a lot of work,” says Mushotzky. “It was not easy to do.”

But they did it, and Mushotzky says the resulting mass—428 times the mass of the sun, if you’re counting—is a reasonably precise figure. “I wouldn’t bet my house on it,” he says. “But I might bet my car.”

If that answer holds up, it could help solve a longstanding mystery of astrophysics. There’s no way a multi-million- or billion-solar-mass black hole could form directly. The giants that lie at the cores of galaxies must have built up over time, from small seeds. But if the seeds were only a few tens of Suns in mass, it’s hard to see how they could have grown quickly enough to reach full size by just a billion years after the Big Bang–which they nevertheless did.

A black hole like M82 X-1 would have given those giants a head start, however. So it’s tantalizing to wonder if this and other objects like it may be leftovers from the earliest days of the cosmos—the potential seeds of giant black holes that somehow failed to sprout, and which are still hanging around in their original form.

If so, they’re like living fossils from the earliest period of cosmic history. It’s an idea Mushotzky calls “highly speculative at this point.” But it’s also highly intriguing.

TIME astronomy

Now We Know How This Giant, Earth-Bound Asteroid Is Held Together, We Can Learn How to Destroy It

Asteroid entering Earth's atmosphere
Erik Simonsen—Getty Images

New discovery might help Earth avert a collision with a menacing asteroid with a 1 in 300 chance of hitting the planet in 2880

An asteroid pointed toward Earth set to arrive in the year 2880 AD may not destroy all life as we know it after all, now that scientists know what’s likely not to work if we need to avert a collision.

Scientists at the University of Tennessee have discovered new cohesive forces that hold giant asteroids together, called van der Waals, that have brought scientists closer to understanding destructive asteroids that threaten to hit Earth.

The discovery could rule out previous methods scientists have proposed for dealing with rogue asteroids.

Previous research has shown that asteroids, which are loose piles of rubble, are held together by gravity. But scientists have now found that some asteroids—like the massive 1950 DA, which could smash into Earth in 2880—are spinning too quickly and defy the force of gravity, and would simply fall apart were they not held together by other means.

“We found that 1950 DA is rotating faster than the breakup limit for its density,” said Ben Rozitis, a postdoctoral researcher at the University of Tennessee. “So if just gravity were holding this rubble pile together, as is generally assumed, it would fly apart. Therefore, interparticle cohesive forces must be holding it together.”

The presence of cohesive forces in massive, life-threatening asteroids means that colliding a large object against the incoming asteroid could actually worsen the impact’s effect, potentially destabilizing the cohesive forces keeping the asteroid together and breaking it into several large asteroids headed for Earth.

That means destroying incoming asteroids with rockets a la the 1979 video game Asteroids may be a no-go. No word yet on the Armageddon (1998) solution, which involved burying a massive nuclear warhead below the surface of the Asteroid.

The asteroid 1950 DA is believed to have a 1-in-300 chance of striking Earth in the year 2880. If it does, scientists believe it would wipe out life on Earth and cause tsunamis and mass extinction.

TIME space

A Satellite Took Pictures of Another Satellite and Now It’s a GIF

The launch of DigitalGlobe's WorldView-3 is seen from Vandenberg Air Force Base on Wednesday, Aug. 13, 2014.
The launch of DigitalGlobe's WorldView-3 is seen from Vandenberg Air Force Base on Aug. 13, 2014. DigitalGlobe

Well, this is pretty meta

A series of pictures provided to TIME by DigitalGlobe shows what kind of fun you can have when you own multiple satellites.

The images captured the launch of the company’s newest satellite launching into orbit this past Wednesday.

The new WorldView-3 satellite, worth roughly a half-billion dollars and about the size of a small RV, became the highest-resolution commercial satellite in space. DigitalGlobe, the company that funded its manufacture, said it will offer 31-centimeter resolution, much clearer than the current 50-cm aboard the WorldView-2.

Technology aboard the new satellite will, among other things, supply Google Maps with higher resolution photos for “satellite view.”

The satellite that shot the photos was flying at an altitude of over 300 miles, according to DigitalGlobe, and orbiting at a speed of 17,000 mph.

Video of the launch from Vandenberg Air Force Base in California can be seen below.

TIME Pictures of the Week

Pictures of the Week: Aug. 8 – Aug. 15

From the tragic death of Robin Williams and violent riots in Ferguson, Mo. to a balloon festival in Bristol and a dog show in Helsinki, TIME presents the best pictures of the week.

TIME robotics

This Robot Army Can Organize Itself

Harvard University — YouTube

Expect the future to be overrun with millions more like it

Scientists at Harvard University have created an army of over a thousand tiny robots that can communicate with each other to perform complex actions. The breakthrough could lay the framework for future robot brigades that collaborate to execute large tasks such as environmental cleanup.

The 1,024 simple bots, called Kilobots, are each only a few centimeters wide, but communicate with each other using infrared light to create large star- or K-shaped formations. Only the initial instruction to form up needs to be given — after that, Kilobots organize themselves and cooperate with each together to smooth out logjams or redirect bots that have wandered off-course.

Michael Rubenstein, the lead author of the study published in the journal Science, says that Kilobots mimic units found in nature such as a group of ants that link together to forge a river, or a body of cells that assemble to form an organism. “Biological collectives involve enormous numbers of cooperating entities — whether you think of cells or insects or animals — that together accomplish a single task that is a magnitude beyond the scale of any individual,” Rubenstein said in a statement released by the Harvard School of Engineering and Applied Sciences.

Although scientists have directed simple bots to complete tasks before, this is the first time that such a large company has operated together. Radhika Nagpal, one of the researchers in the study, says that the Kilobots demonstrate the potential of robots to self-organize on a larger scale. “Increasingly, we’re going to see large numbers of robots working together, whether its hundreds of robots cooperating to achieve environmental cleanup or a quick disaster response, or millions of self-driving cars on our highways,” Nagpal said in a statement. “Understanding how to design ‘good’ systems at that scale will be critical.”

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