On a quiet morning on Feb. 15, 2013, a meteor entered the Earth's atmosphere at a speed of 40,000 miles per hour (11 miles per second), exploding over Chelyabinsk, Russia with a reported force of 30 atomic bombs. In fact, the shockwave was allegedly so intense that people reported damage up to 75 miles away from the meteor's explosion, which occurred about nine miles above sea level.

Hundreds of studies have been written since then, but scientists are still trying to figure out where it came from, and how it went undetected. It's not like the rock itself was particularly big—about 65 feet—but it continues to leave a mark. Upon its atmospheric entry, the explosion generated a superbolide that scientists say was brighter than the sun; some eyewitnesses at the time reported feeling an intense heat from the fireball.

It must have truly felt like the end of the world.

About 1,500 people were injured due to broken glass and other debris, though no deaths were reported. Although scientists have an idea of where the Chelyabinsk meteor came from, they're still not 100 percent sure. To that end, researchers also aren't sure if it's part of a larger threat. Following the event in 2013, one researcher said, "If humanity does not want to go the way of the dinosaurs, we need to study an event like this in detail."

The bad news is rocks the size of the Chelyabinsk meteor are undetectable from Earth, which means a similar event could happen at any time.

"Another body of this size could hit Earth without warning in the future," said Jiri Borovicka, as astronomer at the Academy of Science of the Czech Republic.

Source: Agenciasinc

Two scientific conferences have heard evidence that at least two Australian birds have learned to use fire, picking up smoldering sticks and dropping them in unburnt territory. The behavior has not been photographed, but numerous sightings have been reported, and is woven into the culture of local Indigenous communities.

Astonishingly, it is only a few decades since textbooks confidently proclaimed that humans were the only tool-making species. In 1960, Jane Goodall's ground-breaking reports of tool use amongst chimpanzees overthrew this theory, and today tool use is studied from dolphins to parrots, with crows revealing a sophistication that outshines many humans.

Fire propagation, however, is considered a bright line marking humans apart from animals. Except that is, by the fourteen rangers interviewed by Bob Gosford, and many Australian Aboriginal people in north-central Australia, who say birds use it too.

Biologists say they have solved the riddle of how a tiny bacterium senses light and moves towards it: the entire organism acts like an eyeball.

In a single-celled pond slime, they observed how incoming rays are bent by the bug's spherical surface and focused in a spot on the far side of the cell.

By shuffling along in the opposite direction to that bright spot, the microbe then moves towards the light.

Other scientists were surprised and impressed by this "elegant" discovery.

Despite being just three micrometres (0.003mm) in diameter, the bacteria in the study use the same physical principles as the eye of a camera or a human.

What makes some words easier to learn than others? Researchers at the Max Planck Institute for Psycholinguistics and Radboud University taught Japanese words to Dutch students and found that ideophones — words that sound like what they mean — are easier to learn than regular words. This suggests that some of our associations between sound and meaning may be universal.

Often, the sound of a word doesn't say much about its meaning: none of the individual sounds in dog mean anything about having four legs or enjoying being scratched behind the ears. This is why a domesticated canine can be referred to as dog in English, hond in Dutch, and inu in Japanese — and why it takes hard work to learn any language.

But not all words are like that. Many languages have words which use the sounds of language in a vivid way to show what the word means: ideophones like kibikibi 'energetic' or bukubuku 'fat'.

Some 53 million years ago, a six-foot, flightless bird roamed a swampy land that is now the frozen Arctic. Researchers confirmed the prehistoric birds presences in the wintry land after re-examining a toe bone found on Ellesmere Island.

Discovered in the 1970s, this is the first evidence suggesting this species exists above the Arctic Circle. The fossil is a match with the toe bones discovered in Wyoming along side other remnants belonging to the prehistoric bird, Gastornis, according to the Chinese Academy of Sciences in Beijing and the University of Colorado Boulder. The exotic bird is believed to have weighed several hundred pounds with a head the size of a horse's.

'The Gastornis material reported from Ellesmere Island is the northernmost record of that taxon in North America,' reads the study published in journal Nature. 'Some galloanserine birds today (such as Ruffed Grouse, Spruce Grouse, Sharp-tailed Grouse, Willow Ptarmigan, and Rock Ptarmigan) are Arctic residents, and even some waterfowl winter above the Arctic Circle.'

The federal government spent $1 million to create an online database that will collect "suspicious" memes and track "misinformation." The project, which is known as the "Truthy Database" is being funded by The National Science Foundation, but it seems as if the operation has some powerful political motivations.

Ironically enough, the project takes its name from a term that was popularized by television personality, Stephen Colbert.

The project will seek to understand how misinformation is spread online, but it will be up to a team of government-funded researchers at Indiana University to decide what type of political speech is true and which is false.

According to the grant for the project, the operation will be open source and the database will be open to the public.

The tale of how one researcher has made nearly every scientific paper ever published available for free to anyone, anywhere in the world.

On the evening of November 9th, 1989, the Cold War came to a dramatic end with the fall of the Berlin Wall. Four years ago another wall began to crumble, a wall that arguably has as much impact on the world as the wall that divided East and West Germany. The wall in question is the network of paywalls that cuts off tens of thousands of students and researchers around the world, at institutions that can't afford expensive journal subscriptions, from accessing scientific research.

On September 5th, 2011, Alexandra Elbakyan, a researcher from Kazakhstan, created Sci-Hub, a website that bypasses journal paywalls, illegally providing access to nearly every scientific paper ever published immediately to anyone who wants it. The website works in two stages, firstly by attempting to download a copy from the LibGen database of pirated content, which opened its doors to academic papers in 2012 and now contains over 48 million scientific papers. The ingenious part of the system is that if LibGen does not already have a copy of the paper, Sci-hub bypasses the journal paywall in real time by using access keys donated by academics lucky enough to study at institutions with an adequate range of subscriptions. This allows Sci-Hub to route the user straight to the paper through publishers such as JSTOR, Springer, Sage, and Elsevier. After delivering the paper to the user within seconds, Sci-Hub donates a copy of the paper to LibGen for good measure, where it will be stored forever, accessible by everyone and anyone.

This was a game changer. Before September 2011, there was no way for people to freely access paywalled research en masse; researchers like Elbakyan were out in the cold. Sci-Hub is the first website to offer this service and now makes the process as simple as the click of a single button.

As the number of papers in the LibGen database expands, the frequency with which Sci-Hub has to dip into publishers' repositories falls and consequently the risk of Sci-Hub triggering its alarm bells becomes ever smaller. Elbakyan explains, "We have already downloaded most paywalled articles to the library ... we have almost everything!" This may well be no exaggeration. Elsevier, one of the most prolific and controversial scientific publishers in the world, recently alleged in court that Sci-Hub is currently harvesting Elsevier content at a rate of thousands of papers per day. Elbakyan puts the number of papers downloaded from various publishers through Sci-Hub in the range of hundreds of thousands per day, delivered to a running total of over 19 million visitors.

Whether it's a jungle hut or a high-rise apartment, your home is covered in bacteria, and new research from the Amazon suggests city dwellers might want to open a window.

Scientists traveled from remote villages in Peru to a large Brazilian city to begin tracking the effects of urbanization on the diversity of bacteria in people's homes. It's a small first step in a larger quest—understanding how different environmental bugs help shape what's called our microbiome, the trillions of bacteria that share our bodies and play a critical role in our health.

"Very little is known about the microbes of the built environment," microbiologist Maria Gloria Dominguez-Bello of New York University, who led the pilot study, said at a meeting of the American Association for the Advancement of Science.

Her team found that as people living in the Amazon rainforest become more urbanized, the kinds of bacteria in their homes change from the bugs mostly found in nature to those that typically live on people, she reported Friday.

Breanna Binder, a University of Washington postdoctoral researcher in the Department of Astronomy and lecturer in the School of STEM at UW Bothell, spends her days pondering X-rays.

As she and her colleagues report in a new paper published Feb. 12 in the Monthly Notices of the Royal Astronomical Society, they recently solved a mystery involving X-rays — a case of X-rays present when they shouldn't have been. This mystery's unusual main character — a star that is pretending to be a supernova — illustrates the importance of being in the right place at the right time.

Such was the case in May 2010 when an amateur South African astronomer pointed his telescope toward NGC300, a nearby galaxy. He discovered what appeared to be a supernova — a massive star ending its life in a blaze of glory.

"Most supernovae are visible for a short time and then — over a matter of weeks — fade from view," said Binder.

After a star explodes as a supernova, it usually leaves behind either a black hole or what's called a neutron star — the collapsed, high-density core of the former star. Neither should be visible to Earth after a few weeks. But this supernova — SN 2010da — still was.

"SN 2010da is what we call a 'supernova impostor' — something initially thought to be a supernova based on a bright emission of light, but later to be shown as a massive star that for some reason is showing this enormous flare of activity," said Binder.

Many supernova impostors appear to be massive stars in a binary system — two stars in orbit of one another. Stellar astrophysicists think that the impostor's occasional flare-ups might be due to perturbations from its neighbor.

For SN 2010da, the story appeared to be over until September 2010 — four months after it was confirmed as an impostor — when Binder pointed NASA's Chandra X-ray Observatory toward NGC300 and found something unexpected.

"There was just this massive amount of X-rays coming from SN 2010da, which you should not see coming from a supernova impostor," she said.

Amid the season known for transforming Nebraska into an outdoor ice rink, a University of Nebraska-Lincoln-led research team has predicted a new molecular form of the slippery stuff that even Mother Nature has never borne.

The proposed ice, which the researchers describe in a Feb. 12, 2016 study in the journal Science Advances, would be about 25 percent less dense than a record-low form synthesized by a European team in 2014.

If the ice can be synthesized, it would become the 18th known crystalline form of water -- and the first discovered in the United States since before World War II.

"We performed a lot of calculations (focused on) whether this is not just a low-density ice, but perhaps the lowest-density ice to date," said Xiao Cheng Zeng, an Ameritas University Professor of chemistry who co-authored the study.

"A lot of people are interested in predicting a new ice structure beyond the state of the art."

This newest finding represents the latest in a long line of ice-related research from Zeng, who previously discovered a two-dimensional "Nebraska Ice" that contracts rather than expands when frozen under certain conditions.

Zeng's newest study, which was co-led by Dalian University of Technology's Jijun Zhao, used a computational algorithm and molecular simulation to determine the ranges of extreme pressure and temperature under which water would freeze into the predicted configuration. That configuration takes the form of a clathrate -- essentially a series of water molecules that form an interlocking cage-like structure.