Species living together are not forced to evolve differently to avoid competing with each other, a notion that that has been debated since the early days of natural selection.

By focusing on ovenbirds, one of the most diverse bird families in the world, a team conducted the most in-depth analysis yet of the processes causing species differences to evolve. They found that although bird species occurring together were consistently more different than species living apart, this was simply an artifact of species being old by the time they meet. In fact, once variation in the age of species was accounted for, coexisting species were actually more similar than species evolving separately.

Solar variation has not strongly influenced climate change, according to a paper which seeks to  overturn a widely held scientific view that lengthy periods of warm and cold weather in the past might have been caused by periodic fluctuations in solar activity.

Research in a narrow time period - the last 1,000 years - examined the causes of climate change in the northern hemisphere and found that until the year 1800, the key driver of periodic changes in climate was volcanic eruptions. These tend to prevent sunlight from reaching the Earth, causing cool, drier weather. Since 1900, greenhouse gases have been the primary cause of climate change.

A new aquifer in the Greenland Ice Sheet holds liquid water all year long in the otherwise perpetually frozen winter landscape. And it's big - 27,000 square miles. 

The reservoir is a "perennial firn aquifer" because water persists within the firn; layers of snow and ice that don't melt for at least one season. Researchers believe it figures significantly in understanding the contribution of snowmelt and ice melt to sea levels.  The Greenland Ice Sheet is vast, covering roughly the same area as the states of California, Nevada, Arizona, New Mexico, Colorado and Utah combined. The average thickness of the ice is 5,000 feet.  

“Should I kill myself? May the artificial intelligence (AI), which humankind will depend on, ponder such questions, decide rationally, and drag us with it in a mercy killing?”

A new population of exploding stars must 'switch off' their radio transmissions before collapsing into a Black Hole. But they emit one last strong beam of highly energetic radiation, known as a gamma-ray burst, before they die.

It was thought all gamma-ray bursts were followed by a radio afterglow.

"But we were wrong. After studying an ultra-sensitive image of gamma-ray bursts with no afterglow, we can now say the theory was incorrect and our telescopes have not failed us," Centre for All-sky Astrophysics (CAASTRO) at Curtin University research fellow Dr. Paul Hancock said.

Texas, the U.S. state that annually generates the most electricity, has transitioned from coal to natural gas for electricity generation and that has not only reduced CO2 emissions but is saving water and making the state less vulnerable to drought.

Cranial surgery is tricky business today. Patients will need an aseptic environment, specialized surgical instruments and copious amounts of pain medication both during and afterward.

In ancient Peru, trepanation  - removing a section of the cranial vault using a hand drill or a scraping tool - was a lot more dangerous, and yet more common. They used it to treat a variety of ailments, from head injuries to heartsickness. 

Excavating burial caves in the south-central Andean province of Andahuaylas in Peru, U.C. Santa Barbara archaeologist Danielle Kurin and colleagues unearthed the remains of 32 individuals that date back to the Late Intermediate Period (ca. AD 1000-1250). Among them, 45 separate trepanation procedures were in evidence. 

The Earth is about 4.6 billion years old but no rocks exist that are older than about 3.8 billion years. However, zircons that were eroded from the sedimentary rock section in the Jack Hills of western Australia, which more than 3 billion years old, were eroded from rocks as old as about 4.3 billion years. These Jack Hills zircons are the oldest recorded geological material on the planet.

Caterpillars of two species of butterflies in Colorado and California aren't waiting for China and India to stop belching out so much CO2 - according to a paper in the journal Functional Ecology, they have already evolved to feed rapidly at higher and at a broader range of temperatures, just in the last 40 years, suggesting to the biologists that they did so in order to quickly to cope with a hotter, more variable climate. 

This represents the first instance where recent climate change has affected physiological traits, such as the internal workings of how the body regulates feeding behavior, said Professor Joel Kingsolver at the University of North Carolina at Chapel Hill.

Sure, post-menopausal women and single men don't need maternity coverage but have to pay for it it anyway. But, the US government can now argue, half of all people are paying for coverage they don't need already.

There's just one problem, argues a new report; while currently only a relative handful of the population has been able to sign up for the mandatory program, when lots of people do sign up for healthcare via the new health insurance exchanges set up by the federal and state governments, the fact that more than 80% of consumers may be unable to make a real estimate of their needs means they will choose a higher cost plan than they need.