Astronomers find the strongest evidence yet for the universe's first stars

Rhodium is one of the most powerful catalytic metals known to chemistry. Small amounts of it can drive reactions that produce millions of tons of useful chemicals every year. But getting rhodium to work well—quickly, selectively, and without degrading—depends heavily on the ligands surrounding it.

Spiders are among Earth's most resourceful predators, nabbing prey by any means necessary. Orb weavers spin webs for capture. Wolf spiders ambush on the ground at night. Almost all spiders use venom when they hunt.

Between 280 and 200 million years ago, a group of animals evolved which would eventually give rise to mammals, including humans: the therapsids. They were first described more than 150 years ago, based on fossils from South Africa. Since then, many more fossils have been discovered.

Scientists in Japan have developed a high-resolution X-ray telescope sharp enough to distinguish an object just 3.5 mm wide from one kilometer away, by combining precision mirror-making technology with space astronomy. To test its performance, they built a first-of-its-kind evaluation system, capable of simulating starlight on the ground to measure the telescope's sharpness before its launch on the US-Japan FOXSI sounding rocket mission. The findings, published in Publications of the Astronomica