A planetary core, without the planet
NASA will be heading to a metal world.
The space agency announced last week that a spacecraft named Psyche will visit an asteroid named Psyche. From radar observations, Psyche the asteroid appears ellipsoid in shape, about as wide as Massachusetts, and quite dense.
Psyche is also very bright, adding to suspicions that it is made of metal. Planetary scientists think it is the nickel-iron core of a small planet that was bashed to pieces early in the history of the solar system. Thus a trip to Psyche could reveal clues about what is at the center of Earth, something scientists will never be able to observe directly. — Kenneth Chang
Bats like their plant nectar sweet — though maybe the plants know better
In lab experiments, bats prefer syrupy nectars high in sugar, but in the wild, they pollinate plants producing mostly watery nectars.
Why? The answer may lie in something called the Weber-Fechner law, which says that animals, including people, commonly perceive physical stimuli in relative increments rather than absolutes. They can be more sensitive to changes in quantity than in quality.
Nectar-feeding bats must consider the volume of available nectar and its sugar concentration. They prefer high levels of both, but the Weber-Fechner law predicts that the bats ought to perceive increases in volume more acutely than they do increases in sugar concentration.
New research confirms it: Bats prefer to pollinate plants that produce more nectar, even if that nectar is less sugary. —Steph Yin
Endangered species and the stuff we buy, all mapped out
Researchers in Norway and Japan have developed maps linking the supply chains of traded commodities in 187 countries with 6,803 animals classified as vulnerable, endangered or critically endangered.
The map looked at the 166 threats stemming from human activity that affect each animal and tracked where the many commodities resulting from that activity eventually wind up.
The regions with the biggest impact were the United States, the European Union and Japan. — Joanna Klein
Prehistoric salsa verde: Paleontologists find tomatillo fossil
The nightshade family contains more than 2,400 different species of plants, including some of the most widely consumed fruits and vegetables in the world, like potatoes, tomatoes and peppers.
Scientists had estimated that the family was about 30 million years old, relatively young for plants. But paleontologists in Argentina have recently discovered 52 million-year-old fossilized tomatillos, which are nightshades.
Small, green and covered in a papery husk, tomatillos look a bit like Chinese lanterns. The berry beneath the sheath is the key ingredient in zesty salsa verde. The new discovery could push the age of the entire nightshade family back to when dinosaurs roamed Earth. — Nicholas St. Fleur