Most living organisms adapt their behavior to the rhythm of day and night. Plants are no exception: flowers open in the morning, some tree leaves close during the night. Researchers have been studying the day and night cycle in plants for a long time: Linnaeus observed that flowers in a dark cellar continued to open and close, and Darwin recorded the overnight movement of plant leaves and stalks and called it "sleep". But even to this day, such studies have only been done with small plants grown in pots, and nobody knew whether trees sleep as well. Now, a team of researchers from Austria, Finland and Hungary measured the sleep movement of fully grown trees using a time series of laser scanning point clouds consisting of millions of points each.

Though a border wall with Mexico is currently a matter of serious discussion in the United States, the aim of which is to prevent the physical movement of people (with few other apparent “benefits”), some walls can actually bring together and preserve communities, rather than divide them.

In only five years, the UN says, around 60 million Africans may be displaced as their land ceases to be arable, a potential humanitarian disaster the scale of which would be unprecedented. This would be devastating to a huge portion of the African continent not only ecologically and economically but socially as well.

That’s where Africa’s ingenious Great Green Wall comes in.

Experts at the United Nations say without action, desertification may claim two-thirds of Africa’s farmlands in under a decade. The Great Green Wall, however, was conceived as a wide-reaching strategy to halt Northern Africa’s rapidly advancing Sahara Desert.

The Great Green Wall, once complete, will stretch an incredible 4,400 miles from Senegal in West Africa to the East African nation of Djibouti. Instead of bricks and mortar, the wall will be made of trees and other vegetation, including plants that can be eaten or used to create medicine.

The idea that the young Earth had a thicker atmosphere turns out to be wrong. New research from the University of Washington uses bubbles trapped in 2.7 billion-year-old rocks to show that air at that time exerted at most half the pressure of today’s atmosphere.

Scientists have had a literal breakthrough off the coast of Mexico.

After weeks of drilling from an offshore platform in the Gulf of Mexico, they have reached rocks left over from the day the Earth was hit by a killer asteroid.

The cataclysm is believed to have wiped out the dinosaurs. "This was probably the most important event in the last 100 million years," says Joanna Morgan, a geophysicist at Imperial College in London and a leader of the expedition.

Since the 1980s, researchers have known about the impact site, located near the present-day Yucatan Peninsula. Known as Chicxulub, the crater is approximately 125 miles across. It was created when an asteroid the size of Staten Island, N.Y., struck the Earth around 66 million years ago. The initial explosion from the impact would have made a nuclear bomb look like a firecracker. The searing heat started wildfires many hundreds of miles away.

A small mammal has sabotaged the world's most powerful scientific instrument.

The Large Hadron Collider, a 17-mile superconducting machine designed to smash protons together at close to the speed of light, went offline overnight. Engineers investigating the mishap found the charred remains of a furry creature near a gnawed-through power cable.

"We had electrical problems, and we are pretty sure this was caused by a small animal," says Arnaud Marsollier, head of press for CERN, the organization that runs the $7 billion particle collider in Switzerland. Although they had not conducted a thorough analysis of the remains, Marsollier says they believe the creature was "a weasel, probably." (Update: An official briefing document from CERN indicates the creature may have been a marten.)

The shutdown comes as the LHC was preparing to collect new data on the Higgs Boson, a fundamental particle it discovered in 2012. The Higgs is believed to endow other particles with mass, and it is considered to be a cornerstone of the modern theory of particle physics.

A small mammal has sabotaged the world's most powerful scientific instrument.

The Large Hadron Collider, a 17-mile superconducting machine designed to smash protons together at close to the speed of light, went offline overnight. Engineers investigating the mishap found the charred remains of a furry creature near a gnawed-through power cable.

i

A small mammal, possibly a weasel, gnawed-through a power cable at the Large Hadron Collider.

Ashley Buttle/Flickr

"We had electrical problems, and we are pretty sure this was caused by a small animal," says Arnaud Marsollier, head of press for CERN, the organization that runs the $7 billion particle collider in Switzerland. Although they had not conducted a thorough analysis of the remains, Marsollier says they believe the creature was "a weasel, probably." (Update: An official briefing document from CERN indicates the creature may have been a marten.)

The shutdown comes as the LHC was preparing to collect new data on the Higgs Boson, a fundamental particle it discovered in 2012. The Higgs is believed to endow other particles with mass, and it is considered to be a cornerstone of the modern theory of particle physics.

Researchers have seen some hints in recent data that other, yet-undiscovered particles might also be generated inside the LHC. If those other particles exist, they could revolutionize researcher's understanding of everything from the laws of gravity, to quantum mechanics.

Unfortunately, Marsollier says, scientists will have to wait while workers bring the machine back online. Repairs will take a few days, but getting the machine fully ready to smash might take another week or two. "It may be mid-May," he says.

What if we could not only clean up the heavy metals in our water systems, but also recycle those metals and reuse them?

A new study from the Institute for Intelligent Systems in Germany and the Institute for Bioengineering of Catalonia in Spain suggests that, soon, we might be doing just that.

People who reported consuming more fast food in a national survey were exposed to higher levels of potentially harmful chemicals known as phthalates, according to a study published today by researchers at Milken Institute School of Public Health (Milken Institute SPH) at the George Washington University. The study, one of the first to look at fast-food consumption and exposure to these chemicals, appears in the journal Environmental Health Perspectives.

 Two new papers appearing in the journal Nature this week are "slam-dunk" evidence that energies from supernovae have buffeted our planet, according to astrophysicist Adrian Melott of the University of Kansas.

Melott offers his judgment of these studies in an associated letter, entitled "Supernovae in the neighborhood," also appearing this week in Nature.

One paper, authored by Anton Wallner and colleagues, proves the existence of ancient seabed deposits of iron-60 isotopes, tracing their source to supernovae occurring about 325 light years from Earth. The second paper, by a team headed by Deiter Breitschwerdt, estimates explosion times of these supernovae, isolating two events: one 1.7 to 3.2 million years ago, and the other 6.5 to 8.7 million years ago.

In a new evolutionary proof of the old adage, 'we are what we eat', Cornell University scientists have found tantalizing evidence that a vegetarian diet has led to a mutation that -- if they stray from a balanced omega-6 to omega-3 diet -- may make people more susceptible to inflammation, and by association, increased risk of heart disease and colon cancer. 

The discovery, led by Drs. Tom Brenna, Kumar Kothapalli, and Alon Keinan provides the first evolutionary detective work that traces a higher frequency of a particular mutation to a primarily vegetarian population from Pune, India (about 70 percent), when compared to a traditional meat-eating American population, made up of mostly Kansans (less than 20 percent). It appears in the early online edition of the journal Molecular Biology and Evolution.