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The Top 10 Science Stories of 2016

This year’s science news really shook things up—and we mean that quite literally. A pair of colliding black holes billions of light years away caused a gravitational wave detector to vibrate, ever so slightly, right here on planet Earth, ushering in a new era in astronomy. There was more troubling news as well: The Zika virus wreaked havoc in South America, forcing the World Health Organization to declare a public health emergency; meanwhile, our planet has continued to warm, breaking records for temperature and for shrinking Arctic sea ice. (We also found out that humans have been tracking climate change much longer than previously thought.) But there was no shortage of more uplifting science news, too—from medical breakthroughs to new insights into human evolution. So here are some of the top science stories of 2016.

1. EINSTEIN’S GRAVITATIONAL WAVES WERE FOUND AT LAST.

Einstein’s theory of gravity, published in 1916, predicted the existence of elusive ripples in the fabric of space, known as gravitational waves. But it wasn’t until the mid-1990s that construction on a pair of enormous gravitational wave detectors in Washington and Louisiana began. The facility, known as LIGO (for Laser Interferometer Gravitational-Wave Observatory), started collecting data in 2002, and began a new run with enhanced sensitivity last fall.

In February, scientists announced that they’d pulled off a discovery 100 years in the making. The LIGO detectors caught a fleeting signal from gravitational waves released by a pair of colliding black holes. And it was no one-off feat: Just four months later, scientists detected another burst of gravitational waves, from another pair of merging black holes.

Astronomers and physicists were on cloud nine. The discovery is more than just a long-awaited confirmation of a vital part of Einstein’s theory, known as general relativity. Scientists believe it will also open up a whole new era of gravitational wave astronomy. The story doesn’t end there: Just a few weeks ago, scientists taking a closer look at the data argued that faint “echoes” in the signals point to deviations from Einstein's theory—so, stay tuned!

2. WE FOUND ANOTHER EARTH. (WELL, SORT OF.)

An artist’s impression of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri. Image Credit: ESO/M. Kornmesser

 
We’ve been tallying up exoplanets, planets that orbit stars beyond our solar system, for some 20 years now. But even so, the discovery of Proxima Centauri b (“Proxima b” for short) was hailed as a momentous finding. Part of the excitement stems from the fact that the Proxima Centauri system is the closest star system to ours—it’s a mere four light-years, or 25 trillion miles, away. The planet is also roughly Earth-sized. But more importantly, Proxima b's orbit lies within the “habitable zone” of its parent star, meaning that conditions are right for liquid water to exist on the planet’s surface, raising the tantalizing possibility that it may harbor life.

But is Proxima b truly Earth-like? It's complicated. The planet orbits much closer to its star than Earth does to the Sun, and tidal forces may have “locked” the planet, forcing it to keep one side perpetually facing its sun, creating a steep temperature gradient between the two hemispheres. Also problematic is that because of its tight orbit, it may be constantly blasted by deadly radiation, in addition to bearing the brunt of a stellar wind (the flow of extremely hot plasma ejected from the surface of a star). This may have blown off the planet’s atmosphere—if it ever had one. Even so, Proxima b will be an exciting area of further research for many years to come.

3. BABIES CAN NOW HAVE THREE PARENTS.

iStock

 
When it comes to human reproduction, things may be about to get more complicated. Earlier this month, the government agency that regulates fertility treatments in the UK gave the green light for clinics to apply for licenses to carry out a procedure called mitochondrial replacement therapy (MRT). The therapy would be offered to women whose DNA puts them at risk of passing on potentially crippling genetic diseases to their children. The technique involves replacing the defective mitochondria in a mother’s egg with healthy mitochondria from a donor. The baby would still inherit the full set of 46 chromosomes from its mother and father, but it would have the donor’s mitochondria, hopefully creating a healthy, happy infant.

4. EARLY HUMANS—AND THEIR COUSINS—REALLY GOT AROUND.

Comparison of Modern Human and Neanderthal skulls from the Cleveland Museum of Natural History. Image Credit: DrMikeBaxter via Wikimedia Commons // CC BY-SA 2.0 

We know that our species, Homo sapiens, originated in Africa and then spread out to conquer the globe, but piecing together the details of those migrations has proven challenging. This year, several new pieces were added to the puzzle. An analysis of stone tools at a site in India suggests that early members of the genus Homo reached Asia 2.6 million years ago—some 500,000 years earlier than previously thought. We’re also learning about the role that climate change played in some of those migrations.

Our Neanderthal cousins made the news, too. It looks like humans and Neanderthals interbred some 40,000 years earlier than we’d guessed from earlier studies, and new evidence suggests that Neanderthals carried out funeral rituals which included the use of fire, animal bones, and antlers.

And remember Homo floresiensis, the so-called “hobbits"? It’s never been clear exactly how these diminutive humans, who lived on the Indonesian island of Flores tens of thousands of years ago, got there—or what lineage they had descended from. But a new analysis of teeth and bones from the original excavation site suggests that they were a dwarfed form of Homo erectus, a human ancestor known to have settled in nearby Java.

5. THE OUTER SOLAR SYSTEM GAVE UP ITS SECRETS.

NASA's Dawn spacecraft determined the hydrogen content of the upper yard, or meter, of Ceres' surface. Blue indicates where hydrogen content is higher, near the poles, while red indicates lower content at lower latitudes. Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

 
Although no human has ventured further than the Moon, we’re learning a lot about the outer planets of our solar system, thanks to telescopes like the Hubble and robotic probes. This year astronomers using the Hubble discovered that enormous salt-water geysers spew up from the surface of Europa, one of Jupiter’s moons. Meanwhile, NASA’s Juno spacecraft finally reached Jupiter on July 4, after a five-year journey, where the craft is studying the giant planet’s atmosphere and its powerful magnetosphere. Even further from home, data from the New Horizons mission to Pluto suggests that giant hills float like icebergs on a sea of nitrogen on the planet’s surface. Even the humble dwarf planets got in on the action this year, with the discovery that Ceres has ice volcanoes and maybe even a thin atmosphere. (Thank you, Dawn spacecraft!)

6. ANIMAL MINDS UNDERSTAND MORE THAN WE KNEW.

Female bonobos hang out at Belgium's Planckendael Zoo. Image Credit: Georges Gobet/AFP/Getty Images

 
For years, scientists believed that only humans had the capacity for a “theory of mind”—the ability to reason about another person’s beliefs. But this year researchers concluded that three species of great apes—chimpanzees, bonobos, and orangutans—have this remarkable ability too. Smaller creatures can’t get inside each other’s heads to quite that degree, but even mice, it turns out, display a certain level of empathy. Researchers found that if healthy mice are placed near mice that are in pain, the healthy mice become more sensitive to pain themselves.

7. ARTIFICIAL INTELLIGENCE BESTED OURS …

South Korean professional Go player Lee Sedol puts his first stone against Google's artificial intelligence program, AlphaGo, during the third Google DeepMind Challenge Match on March 12, 2016 in Seoul, South Korea. Sedol lost four out of five games. Image Credit: Google via Getty Images

 
The ancient Chinese board game of Go has billions upon billions of possible board arrangements—which is why most artificial intelligence (AI) experts imagined that it would be many years, if not decades, before a computer system could beat the best human players. But this March, a program called AlphaGo, developed by Google’s AI division, DeepMind, defeated 18-time world champion Go player Lee Sedol, four games to one. The program used neural networks to analyze some 30 million moves made by human experts, and also learned by playing thousands of games against itself.

8. … AND "BIRD-BRAIN" SHOULD NO LONGER BE AN INSULT.

A crow at Kolkata's Alipore Zoo follows the lead of thirsty humans and drinks from a water fountain. Image Credit: Deshkalyan Chowdhury/AFP/Getty Images

 
It’s just in the past few years that researchers have come to recognize just how clever certain bird species are—especially corvids (crows, jays, and related species). This year scientists discovered that Hawaiian crows are remarkably adept tool users; New Caledonian crows, meanwhile, can bend sticks into hooks. Researchers now believe that certain bird species are just as smart as apes (perhaps because their brain cells are packed together very densely). And in a remarkable story that combined surprising science with an overload of cuteness, we learned that newborn ducklings may have some capacity for understanding abstract concepts.

9. A DINOSAUR’S TAIL TELLS A TALE PRESERVED IN AMBER.

Royal Saskatchewan Museum (RSM/ R.C. McKellar)

 
It died almost 100 million years ago, but thanks to the preserving power of amber, a Cretaceous-era feathered dinosaur—or at least, a small bit of its tail—has survived the ravages of time in near-pristine condition. Discovered in Myanmar, the feather is believed to have belonged to a juvenile theropod, a family that includes not only dinosaurs but also modern birds. Although the feathers are impressive, researchers can’t be sure if the little dino could fly. The feathers may have regulated its temperature, or they may have been decorative.

10. WE FOUND PROOF THAT BABYLONIAN ASTRONOMERS TRACKED JUPITER.

Mathieu Ossendrijver in Science

 
We already knew that the Babylonians, who lived in what is now Iraq, had pretty advanced mathematical and astronomical knowledge, but a new analysis of four ancient tablets dating from between 350 and 50 BCE suggests that they used sophisticated geometrical techniques to keep track of Jupiter’s position in the night sky. That’s something European astronomers wouldn’t begin doing until some 14 centuries later.

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Keith Holmes/Hakai Institute
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Stones, Bones, and Wrecks
Ice Age Human Footprints in Canada Reveal a Walk on the Beach Taken 13,000 Years Ago
Calvert Island
Calvert Island
Keith Holmes/Hakai Institute

The prehistoric mariners rowed their canoe into a secluded channel and then onto the island's sandy beach, just above the high-tide mark. One person got out of the boat and stood for a moment, facing northwest. Others, including another barefoot adult and child, followed the leader and walked toward higher, drier land.

Today, roughly 13,000 years later, their footprints have been preserved in a layer of sediment and confirmed to date from the last ice age. The discovery, on Calvert Island on the central coast of British Columbia, Canada, adds to the growing body of evidence that suggests ancient humans crossed from Asia to North America and traveled south along the Pacific shoreline.

"This finding provides evidence of the seafaring people who inhabited this area during the tail end of the last major ice age," said University of Victoria anthropologist Duncan McLaren, lead author of the new study in the journal PLOS One, in a statement.

Archaeologists on Calvert Island, British Columbia, Canada
Researchers Daryl Fedje (left) and Duncan McLaren (right) dig at the Calvert Island site.
Grant Callegari/Hakai Institute

Most anthropologists believe that early peoples migrated from Asia to North America across Beringia, the region where Russia's Chukchi Peninsula and Alaska face each other across the Bering Strait. Then the migrants took two possible routes. One popular theory, proposed in the 1930s, suggests people traveled south along an ice-free corridor that lay on the eastern slope of the Rocky Mountains where two colossal ice sheets split from one other. A more recent theory proposes that they sailed along a coastal route from Alaska to Washington State.

The coastal route lies within the territories of the Heiltsuk First Nation and Wuikinuxv First Nation. Their oral histories describe how the scattered islands between the open ocean and the edge of the ice sheet remained unglaciated. On these refuges, their ancestors subsisted on the abundant fish, shellfish, and marine mammals and likely used watercraft to travel between the islands. "Heiltsuk oral history talks about our people living in our territory before the ice age, and talks about the physical features of the landscape that our people witnessed change over time due to the ice, which influenced things like place names in our territory," William Housty, chair of the Heiltsuk Integrated Resource Management Department board of directors, tells Mental Floss.

Archaeological evidence affirming the histories is scarce, in part because few researchers have focused on the area. In 2014, McLaren and colleagues from the University of Victoria and the Hakai Institute, along with representatives of the First Nations, began combing the beach at a Calvert Island site called EjTa-4 for sediments dating back to the late Pleistocene epoch (also known as the Ice Age, which ended 11,700 years ago). Back then, the sea level around Calvert Island was 6.5 to 10 feet lower than it is today, so the team concentrated on the intertidal zone. After probing several test holes, they found what appeared to be footprints near the base of a huge shell midden.

A 13,000-year-old human footprint on Calvert Island, British Columbia, Canada
A photo of Track #17 beside a digitally enhanced image of the same feature. Note the toe impressions and arch, which indicate that this is a right footprint.
Duncan McLaren

Over the next three field seasons, they continued to excavate a 6.5-foot-by-13-foot pit, removing strata of sand, pebbles, and organic matter before striking the layer of clay. "The site was below the high-tide water line, so we only had one day from the time we opened the last layer. When the high tide came up it would wash everything away," Jennifer Walkus, the research liaison between the Wuikinuxv Nation and Hakai Institute, tells Mental Floss. "We had an idea from the test pit the previous year that there might be footprints, so we knew that day was going to be busy. It was amazing as the last layer was pulled up and the measurements were taken."

In the substrate, the team found 29 individual human tracks, darkened by time, left by at least three different people—two adults and a child—based on the dimensions of the individual prints. "The fact that they were footprints was more and more obvious as the measurements came in and there were three lengths," Wallkus says. The orientation of some of the tracks at the ancient shoreline indicated that a group of people may have disembarked from a watercraft and walked northwest, toward higher ground, with their backs to the prevailing wind.

Researchers also collected samples of clay and fragments of shore pine from the sand underneath the prints. Radiocarbon dating confirmed that the pine bits, and the footprints, were between 13,317 and 12,633 years old.

"I can't speak for the Nation as a whole, but for me, it's a validation of the fact that we have been here for much longer than the previous narrative," Walkus says. "The fact that these footprints put people in the vicinity in the time of glacial recession underlines that our legends are grounded in living in our area over huge spans of time."

When William Housty, who was not present at the dig, heard of the discovery, "I immediately started to think about our first ancestors and the stories of their origin," he says. "I also thought that, once again, science [and] archeology have confirmed what our oral history has been telling us all along."

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University of York
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Stones, Bones, and Wrecks
UK Archaeologists Have Found One of the World’s Oldest 'Crayons'
University of York
University of York

A prehistoric chunk of pigment found near an ancient lake in England may be one of the world's oldest crayons, Colossal reports. The small object made of red ochre was discovered during an archaeological excavation near Lake Flixton, a prehistoric lake that has since become a peat wetland but was once occupied by Mesolithic hunter-gatherers. Though it’s hard to date the crayon itself, it was found in a layer of earth dating back to the 7th millennium BCE, according to a recent study by University of York archaeologists.

Measuring less than an inch long, the piece of pigment is sharpened at one end, and its shape indicates that it was modified by a person and used extensively as a tool, not shaped by nature. The piece "looks exactly like a crayon," study author Andy Needham of the University of York said in a press release.

A pebble of red ochre thought to be a prehistoric crayon
University of York

The fine grooves and striations on the crayon suggest that it was used as a drawing tool, and indicate that it might have been rubbed against a granular surface (like a rock). Other research has found that ochre was collected and used widely by prehistoric hunter-gatherers like the ones who lived near Lake Flixton, bolstering the theory that it was used as a tool.

The researchers also found another, pebble-shaped fragment of red ochre at a nearby site, which was scraped so heavily that it became concave, indicating that it might have been used to extract the pigment as a red powder.

"The pebble and crayon were located in an area already rich in art," Needham said. "It is possible there could have been an artistic use for these objects, perhaps for coloring animal skins or for use in decorative artwork."

[h/t Colossal]

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