Scientists have discovered a new way to manipulate the magnetic structure of certain materials to form a kind of magnet known as fragmented spin ice. The resulting material possesses some of the weirdest magnetic properties known to science. Researchers are still trying to figure out exactly how these weird magnets behave, and learning to harness them could one day lead to novel applications. The discovery was published last month in the journal Nature Communications.

Tiny, frustrated magnets

Inside every material there are magnetic and nonmagnetic atoms. While both are essential for determining the material's many properties, the magnetic atoms control the magnetic properties. Acting like individual tiny magnets, the magnetic atoms collectively determine the overall magnetic properties of the material, which depends on the strength and coordinated orientation of each of these tiny atom-sized magnets. This is how we get a fridge magnet that behaves differently from the surface of the fridge. And it's why both differ when compared to the plastic fridge handle. The strength and orientation of the tiny magnets within each of those three items are closely related to a fundamental property of individual nuclei and electrons known as spin. Because of this close relationship, sometimes scientists simply call the tiny magnets "spins."

In spin ice the tiny magnets, or spins, are arranged in a very specific way. Unlike most magnetic materials, which take up relatively straightforward formations, such as lining up along a single direction, or just pointing in random directions, the individual spins inside a spin ice material have no simple way to organize themselves. This is usually due to the geometric arrangement of the atoms themselves -- when the atoms are put together in a certain way, the individual spins simply can't find a position that's consistently comfortable, as if they're trying to fit together like a bunch of badly built floor tiles.

If giants were playing a game of Jenga with countries as their table-tops, Mexico would be one of the last locations to get picked.

The country sits atop three of the Earth's largest tectonic plates - the North American plate, the Cocos Plate, and the Pacific Plate. Whenever these chunks of crust grind or butt up against one another, earthquakes happen. As a former lakebed, Mexico City is also home to soft soil that essentially acts as an amplifier for tremors, often making smaller earthquakes feel much larger.

On Tuesday, a deadly quake reverberated along the boundary between the Cocos and the North American plate as the southern-most plate slid beneath its northern neighbor. The 7.1-magnitude temblor, which struck about 3 miles northeast of the city of Raboso, happened less than two weeks after the country was struck by an even more powerful 8.1-magnitude quake and 32 years to the day after a deadly magnitude 8.1 quake killed more than 9,500 people in Mexico City.

If you understand how stars work, you can observe the physical properties of one of them and extrapolate its age, and know when it had to have been born. Stars undergo a lot of changes as they age: their radius, luminosity, and temperature all evolve as they burn through their fuel. But a star's lifespan, in general, is dependent on only two properties that it's born with: its mass and its metallicity, which is the amount of elements heavier than hydrogen and helium present within. The oldest stars we've found in the Universe are nearly pristine, where almost 100% of what makes them up is the hydrogen and helium left over from the Big Bang. They come in at over 13 billion years old, with the oldest at 14.5 billion. And this is a big problem, because the Universe itself is only 13.8 billion years old.

The programme could help patients receive medication early to manage the disease.

Researchers have created an artificial intelligence (AI) programme that can detect signs of Alzheimer's disease up to ten years before symptoms appear.

Developed by a team at the University of Bari, in Italy, the computer system scans the brain for "tiny structural changes" that indicate the early stages of the disease, reports Engadget.

The AI was fed 38 MRI scans from Alzheimer's patients, and 29 from healthy patients, the website says, to help it learn common patterns in neurological activity and the symptoms of the disease.

What scientists thought caused certain classes of northern lights is not what causes certain classes of northern lights.

In a landmark study that has toppled what scientists know about the night sky, UAlberta physicists Robert Rankin and Dmytro Sydorenko found that the ionospheric feedback instability (IFI)-the mechanism thought to be the cause of certain types of northern lights-not only doesn't cause northern lights, it may not even exist at all.

"These findings fly in the face of what is now commonly accepted in the world of space science," said Rankin. "Our research shows that conditions necessary for the ionospheric feedback instability to occur are very unlikely, meaning it cannot be the cause of something as regular as the Aurora Borealis."

After 20 years, nearly 300 orbits and pioneering discoveries, the spacecraft plunges to its death in Saturn's atmosphere

Cassini went down fighting.

After 20 years in space and 13 years orbiting Saturn, the veteran spacecraft spent its last 90 seconds or so firing its thrusters as hard as it could to keep sending Saturnian secrets back to Earth for as long as possible.

The spacecraft entered Saturn's atmosphere at about 3:31 a.m. PDT on September 15 and immediately began running through all of its stabilizing procedures to try to keep itself upright. The signal that Cassini had reached its destination arrived at Earth at 4:54 a.m., and cut out about a minute later as the spacecraft lost its battle with Saturn's atmosphere.

A series of rapid-fire solar flares is providing the first chance to test a new theory of why the sun releases its biggest outbursts when its activity is ramping down. Migrating bands of magnetism that meet at the sun's equator may cause the biggest flares, even as the sun is going to sleep.

A single complex sunspot called Active Region 2673 emitted seven bright flares - powerful bursts of radiation triggered by magnetic activity - from September 4 to September 10. Four were X-class solar flares, the most intense kind. The strongest, released at 8:02 a.m. EDT on September 6, was an X9.3. The most powerful flare since 2006 (and the eighth largest since monitoring started in June 1996), it disrupted shortwave radio communication over Africa for up to an hour. It also flung a blob of energetic plasma, called a coronal mass ejection, speeding toward Earth, which sparked auroras the night of September 7 that were visible as far south as Arkansas.

All that activity is counterintuitive, as the sun is near the end of an unusually weak solar cycle, which began in 2008 (SN: 11/2/13, p. 22). The sun's magnetic activity waxes and wanes roughly every 11 years, generating more dark sunspots at the peak of the cycle and fewer at the trough.

Robots made out of single strands of DNA could soon be used to precisely target and treat some of the world's deadliest diseases.

Developed by researchers from the California Institute of Technology, the microscopic machines have feet, arms and hands included in their design so they can maneuver and pick up molecules. They then recognize specific drop-off points and respond to signals telling them when to drop their cargo.

Astronomers have discovered that the well-studied exoplanet WASP-12b reflects almost no light, making it appear essentially pitch black. This discovery sheds new light on the atmospheric composition of the planet and also refutes previous hypotheses about WASP-12b's atmosphere. The results are also in stark contrast to observations of another similarly sized exoplanet.

Using the Space Telescope Imaging Spectrograph (STIS) on the NASA/ESA Hubble Space Telescope, an international team led by astronomers at McGill University, Canada, and the University of Exeter, UK, have measured how much light the exoplanet WASP-12b reflects-its albedo-in order to learn more about the composition of its atmosphere.

The results were surprising, explains lead author Taylor Bell, a Master's student in astronomy at McGill University who is affiliated with the Institute for Research on Exoplanets: "The measured albedo of WASP-12b is 0.064 at most. This is an extremely low value, making the planet darker than fresh asphalt!" This makes WASP-12b two times less reflective than our Moon which has an albedo of 0.12. Bell adds: "The low albedo shows we still have a lot to learn about WASP-12b and other similar exoplanets."

Insects and plants have an important ancient defence mechanism that helps them to fight viruses. This is encoded in their DNA. Scientists have long assumed that vertebrates - including humans - also had this same mechanism. But researchers at KU Leuven have found that vertebrates lost this particular asset in the course of their evolution.

The possibilities encoded in our DNA are expressed via RNA. Conversely, RNA interference (RNAi) can also suppress the expression of a specific gene. Insects and plants use this RNAi mechanism to defend themselves against viruses, among other things. With a little help, insects and plants can even be made resistant to certain diseases through this RNAi mechanism. Examples include so-called genetically modified crops.

It seems only logical to assume, then, that humans can be protected against specific diseases in a similar way. However, past experiments to this effect have proven to be a challenge. Researchers from the Animal Physiology and Neurobiology unit at KU Leuven have now shown why this is the case.