For many centuries, scientists dismissed stories of stones falling from the sky as featherbrained peasant tales — until April 26, 1803, when meteorites rained down on the town of L’Aigle in Normandy, France, and were established as fact by a noted French scientist.

For the next 200-plus years, scientists generally believed that asteroids — small, rocky objects that are called meteorites when they land on earth — are the building blocks of planetary material. Now, a new theory has emerged: that asteroids may actually be the byproduct of planet formation.

The clues lie in the tiny bead-like grains of solidified melted rock called “chondrules” found in meteorites, says Jay Melosh, a distinguished professor of earth, atmospheric and planetary sciences and professor of physics and aerospace engineering. Read more.

Here in the United States, where lead-based paint was banned in 1978 and leaded gasoline in 1986, we think of childhood lead poisoning as largely a relic of our past. But in China, where lead regulations have only recently been enacted, medical professionals are eager to find more accurate ways of measuring toxicity.

Linda Nie, an associate professor of health sciences, has developed a portable X-ray fluorescence (XRF) system to measure lead in bone in vivo. She’s now collaborating with physicians at Xinhua Hospital in Shanghai to validate the unit among a group of children with lead poisoning.

While blood lead reflects short-term exposure, bone lead shows long-term exposure, since the majority of lead accumulates in the bone. Nie’s unit shoots a low-energy X-ray into the tibia bone and collects specific signals if lead is present in the bone.

From lighting up color TVs to recharging hybrid car batteries, rare-earth metals like lanthanum have become essential in our tech-driven world. But the inefficiencies and hazards of extracting these bright, silvery metals have prompted Nien-Hwa Linda Wang to engineer a more efficient, environmentally-friendly method.

In 2015, the Purdue Research Foundation filed a patent for Wang’s method for producing high-purity rare earth elements. Crude mixtures of rare earth elements are first separated from rare earth ores or coal ash.The mixtures are then dissolved in a solution and separated into pure fractions using an advanced chromatography method.

The new design produces double the current yield with purities greater than 95 percent. “This is very clean and very compact, and the impact on the environment is much, much less,” says Wang, the Maxine Spencer Nichols Professor in Chemical Engineering. “We use benign chemicals for this very reason.”

Researcher Klein Ileleji knows the challenges farmers in developing countries face when drying crops. A native of Nigeria, he grew up in towns with unreliable power sources and knew small-scale farmers who couldn’t afford dryers and whose harvests were lost to pests and mold. Later as an agricultural engineer and specialist in grain production, he also knew there had to be a solution.

While working on a solar drying system for maize farmers in Senegal and Kenya, Ileleji, an agricultural and biological engineering professor and an extension engineer, stumbled across an idea.

Why not use the solar drying system to generate power as well? And then he spun off a third use — drying trays for the system that also can be used independently as small dehydrators. The DEHYTRAY, a portable solar dehydrator, was born.