Each week we uncover the most interesting and informative articles from around the world, here are 10 of the coolest stories in science this week.
An Unexplainable Structure
One day, about a billion years ago, Earth’s inner core had a growth spurt. The molten ball of liquid metal at the center of our planet rapidly crystallized due to lowering temperatures, growing steadily outward until it reached the roughly 760-mile (1,220 kilometers) diameter to which it’s thought to extend today.
Weirder still, the researchers said, once you account for this missing detail, the science seems to suggest that Earth’s inner core shouldn’t exist at all. [Read more about the core.]
An Unusual Look
Scientists have put a smiling face to one of the first human residents of Great Britain.
This color combination would be unusual today, but ancient DNA evidence suggests that it was the norm among the hunter-gatherers of northern continental Europe during the Mesolithic, Booth said. Pale eyes apparently evolved in early Europeans before pale skin, which emerged after the advent of agriculture, he said. [Read more about the ancient people.]
You can’t see them or feel them, but millions of airborne viruses are wafting around you each day, and billions more microbial travelers are descending everywhere on Earth, after riding air currents around the world.
In fact, viruses are the most abundant microbes on the planet, the study authors reported. The total estimated number of viruses is so staggeringly large that if all Earth’s viruses were collected together they would cover an area spanning 100 million light-years. [Read more about the falling viruses.]
Dangers of a Meltdown
When the mercury’s rising in your thermometer, it may also be rising in the ocean.
Previous studies have attempted to account for the billions of tons of carbon dioxide, methane and even “zombie pathogens” that could be loosed into the air and the oceans by melting permafrost. The environmental impact of a large-scale mercury leak, however, remains an unpredictable problem. [Read more about the time bomb.]
Scientists may have just pecked new holes in the widely held idea that woodpeckers’ brains suffer no ill effects from the considerable force generated by their high-speed pecking.
For generations, scientists accepted that woodpeckers didn’t develop abnormalities in their brains from the repeated impacts. Then again, no one had ever checked woodpecker brains for signs of damage, the study authors noted. [Read more about the birds.]
A Vast Conspiracy
A believer in flat-Earth conspiracies took another shot at shooting himself toward the stratosphere in a homemade rocket. Once again, it fell flat.
That subculture is flat-Earthers, people who argue that centuries of observations that the Earth is round (including astronaut photographs from space and the fact that round-the-world travel itineraries work) are either mistaken or part of a vast cover-up. Instead, flat-Earthers argue, the planet is a disk. [Read more about the theory.]
Solving a Viking Mysery
Archaeologists could barely believe their luck when they uncovered a mass grave in the 1980s that appeared to be filled with the remains of more than 200 warriors from the Viking Great Army. But subsequent radiocarbon dating cast doubt on this idea, showing that some of the remains dated to hundreds of years before the Viking Age.
According to historical records, the Great Army spent the winter in Repton in A.D. 873-874 and attacked the king of Mercia, an Anglo-Saxon kingdom, sending him into exile. [Read more about the mass grave.]
Women in History
The tomb of a woman named Hetpet, who became a senior official in the royal palace, has been discovered in a cemetery on the Giza Plateau, archaeologists from Egypt’s antiquities ministry announced today (Feb 3). [Read more about tomb.]
Beating the Epidemic
The number of Americans touched by the opioid epidemic has reached alarming proportions. Millions of people are affected each year, and death rates from overdoses have quadrupled since 1999, numbering in the tens of thousands annually, according to the National Institute on Drug Abuse (NIDA). But there may be a less-risky alternative to opioids for alleviating certain types of chronic pain: marijuana. [Read more about the options.]
On April 1, 2014, the American Physical Society announced a landmark change in policy: All scientific papers authored by cats would henceforth become freely available to the public.
As a colleague pointed out while editing the draft, Hetherington listed himself as the study’s sole author, yet he had nevertheless written the entire paper using the “we” pronoun. This was against the journal’s style rules, the colleague noted. Hetherington’s paper would surely be rejected if it wasn’t retyped. [Read more about the cat.]