Asteroids are much harder to destroy than previously thought, new modelling shows.

The research, published in the journal Icarus, shows that an asteroid damaged in a collision - by another asteroid, for instance, or a nuclear missile fired at it in the blind hope that doing so will prevent it from smacking into the planet with catastrophic consequences - will substantially reconstruct itself because of the strong gravitational pull of its still-intact core.

The modelling, funded by NASA, substantially updates and contradicts earlier research that showed that a collision between a small asteroid and a large one would completely demolish the latter, the destruction facilitated by the rapid transit of cracks right through it.

The new study, conducted by Charles El Mir and KT Ramesh, of Johns Hopkins University, US, and Derek Richardson, of the University of Maryland, US, applies more fine-grain analysis and arrives at a distinctly different conclusion.

At issue, fundamentally, is the way rocks react to energetic impacts. This process is well understood at what can be called "laboratory scale", wherein real-world and simulated experiments use rocks roughly the size of a human fist.

But asteroids of a magnitude big enough to worry NASA scientists - or tempt would-be space-miners - are considerably larger than that. They might, indeed, be roughly the size of Berlin.

For almost a decade, astronomers have tried to explain why so many pairs of planets outside our solar system have an odd configuration - their orbits seem to have been pushed apart by a powerful unknown mechanism. Yale researchers say they've found a possible answer, and it implies that the planets' poles are majorly tilted.

The finding could have a big impact on how researchers estimate the structure, climate, and habitability of exoplanets as they try to identify planets that are similar to Earth. The research appears in the March 4 online edition of the journal Nature Astronomy.

NASA's Kepler mission revealed that about 30% of stars similar to our Sun harbor "Super-Earths." Their sizes are somewhere between that of Earth and Neptune, they have nearly circular and coplanar orbits, and it takes them fewer than 100 days to go around their star. Yet curiously, a great number of these planets exist in pairs with orbits that lie just outside natural points of stability.

That's where obliquity - the amount of tilting between a planet's axis and its orbit - comes in, according to Yale astronomers Sarah Millholland and Gregory Laughlin.

Researchers have discovered two previously unknown massive craters on Earth, the most recent estimated to have been produced by an impact only 800,000 years ago.

The craters - one in Western Australia and the other in Nicaragua - are revealed in a pair of papers published in the journal Meteoritics and Planetary Science.

In one sense, the Australian crater, in a location known as Yallalie, about 200 kilometres north of the state capital, Perth, has long been hiding in plain sight.

Buried deep beneath the surface, it was first tentatively identified as an impact site in 1992, after its discovery two years earlier during oil drilling exploration.

Subsequent studies of the 12-kilometre-wide circular formation, which also features a raised central structure three kilometres wide, identified it as the result of several meteorite impacts.

Astronomers have discovered a distant galaxy that's giddily blowing bubbles like a toddler with a glass of chocolate milk. Unlike milk bubbles, however, these two huge galactic balloons are filled with gas, stretch a few thousand light-years across and appear to be crackling with charged particles 100 times more energetic than any found on Earth.

Using data from the Hubble Space Telescope and NASA's Chandra X-Ray Observatory, researchers detected the bubbles jiggling near the center of a galaxy named NGC 3079, located about 67 million light-years away from Earth. Bubbles like these are known as "superbubbles" because, well, they're supersized. According to the team's study in the Feb. 28 issue of The Astrophysical Journal, one of the newly discovered bubbles measures 4,900 light-years across, and the other measures 3,600 light-years across. (For comparison, the diameter of Neptune's orbit around the sun is about 5.6 billion miles, or 9 billion kilometers - one-thousandth of one light-year.)

Superbubbles form when powerful shock waves shove the gases released by stars far into space, leaving a bubble-shaped cavity behind. Scientists still don't fully understand how these massive gas cavities form.

Like the mythical monster Medusa, a newfound giant virus turns its host to "stone." But, luckily for us, its hosts are amoebas.

Now called Medusavirus for its seemingly mythical powers, the strange virus was pulled from the muddy waters of a hot spring in Japan, according to a new study, published Feb. 6 in the Journal of Virology. Medusavirus belongs to a group known as "giant viruses," which have exceptionally large genomes compared with most other viruses.

The virus infects single-celled organisms known as Acanthamoeba castellanii, a type of amoeba. When the researchers infected these amoebas in lab dishes, they found that the virus prompted the amoebas to develop a thick outer "shell" and enter a dormant state known as encystment. (The amoeba can naturally enter this state in response to stress in its environment.) That behavior reminded the researchers of the mythological monster Medusa, who, according to Greek mythology, could turn onlookers to stone with her gaze.

Some months ago, I participated in a two-week experiment that involved using a smartphone app to track every morsel of food I ate, every beverage I drank and every medication I took, as well as how much I slept and exercised. I wore a sensor that monitored my blood-glucose levels, and I sent in a sample of my stool for an assessment of my gut microbiome. All of my data, amassed with similar input from more than a thousand other people, was analyzed by artificial intelligence to create a personalized diet algorithm. The point was to find out what kind of food I should be eating to live a longer and healthier life.

The results? In the sweets category: Cheesecake was given an A grade, but whole-wheat fig bars were a C -. In fruits: Strawberries were an A+ for me, but grapefruit a C. In legumes: Mixed nuts were an A+, but veggie burgers a C. Needless to say, it didn't match what I thought I knew about healthy eating.


It turns out, despite decades of diet fads and government-issued food pyramids, we know surprisingly little about the science of nutrition. It is very hard to do high-quality randomized trials: They require people to adhere to a diet for years before there can be any assessment of significant health outcomes. The largest ever - which found that the "Mediterranean diet" lowered the risk for heart attacks and strokes - had to be retracted and republished with softened conclusions. Most studies are observational, relying on food diaries or the shaky memories of participants. There are many such studies, with over a hundred thousand people assessed for carbohydrate consumption, or fiber, salt or artificial sweeteners, and the best we can say is that there might be an association, not anything about cause and effect. Perhaps not surprisingly, these studies have serially contradicted one another. Meanwhile, the field has been undermined by the food industry, which tries to exert influence over the research it funds.

Think sleeping in on the weekend can repair the damage from a week of sleepless nights?

Not so, according to new CU Boulder research published today in the journal Current Biology.

In fact, on some metabolic health measures, trying to play catch-up for a few days and then returning to poor sleep habits may make things worse.

"Our findings suggest that the common behavior of burning the candle during the week and trying to make up for it on the weekend is not an effective health strategy," said senior author Kenneth Wright, an Integrative Physiology professor and director of the Sleep and Chronobiology Lab.

Previous research by Wright and others has shown that insufficient sleep can boost risk of obesity and diabetes, in part by boosting the urge to snack at night and decreasing insulin sensitivity - or the ability to regulate blood sugar. Some adverse metabolic health impacts can kick in after just one night of lost sleep, recent CU Boulder research has shown.

Sleeping in on the weekend can help the body recover mildly during those two days, studies suggest. But the effects don't last.

A global biodiversity crash 251.9 million years ago has revealed how ecosystems respond to extreme perturbation. The finding that terrestrial ecosystems were less affected than marine ones is unexpected.

Changes in Earth's biodiversity recorded in fossils over various spatial and timescales reveal the comings and goings of species as they emerge and go extinct, and offer insights into how both species and the ecosystems they inhabit respond to perturbation. These patterns of the past provide models that might help us to understand the changes that life on Earth will experience in the future. The end-Permian mass extinction, often called the mother of mass extinctions¹, is a focus of such studies. Large waves of extinctions occurred over a time interval of 60,000 to 120,000 years² at the end of the Permian period, which lasted from 298.9 million to 251.9 million years ago. Fossil studies indicate that more than 90% of marine invertebrates went extinct³ as a consequence of extreme perturbations of the conditions on Earth, including intense volcanic activity. Writing in Nature Communications, Fielding et al.⁴ and Nowak et al.⁵ reveal what happened to terrestrial plants during the end-Permian crisis. Both contributions are well supported by an array of data, and both tell a slightly different story.

A comprehensive worm survey of farms in England has shown they are rare or absent in two out of five fields, reflecting widespread historical over-cultivation.

The #60minworms project required volunteer farmers to dig 10 small pits across a field so that both the overall number and diversity of earthworms could be counted.

The project, organised by Jackie Stroud, a NERC soil security fellow at Rothamsted Research, and funded by the Natural Environment Research Council (NERC), covered 1,318ha of farmland in England.

One of the project's main aims was to find the baseline of farmland earthworm populations against which farmers could test their soil health both now and in the future.

Rare or absent

Scientists love a good mystery. But it's more fun when the future of humanity isn't at stake.

This enigma involves methane, a potent greenhouse gas. Twenty years ago the level of methane in the atmosphere stopped increasing, giving humanity a bit of a break when it came to slowing climate change. But the concentration started rising again in 2007 - and it's been picking up the pace over the last four years, according to new research.

Scientists haven't figured out the cause, but they say one thing is clear: This surge could imperil the Paris climate accord. That's because many scenarios for meeting its goal of keeping global warming "well below 2 degrees Celsius" assumed that methane would be falling by now, buying time to tackle the long-term challenge of reducing carbon dioxide emissions.


"I don't want to run around and cry wolf all the time, but it is something that is very, very worrying," said Euan Nisbet, an Earth scientist at Royal Holloway, University of London, and lead author of a recent study reporting that the growth of atmospheric methane is accelerating.