Volcanic rock samples collected during NASA's Apollo missions bear the isotopic signature of key events in the early evolution of the Moon, a new analysis found. Those events include the formation of the Moon's iron core, as well as the crystallization of the lunar magma ocean—the sea of molten rock thought to have covered the Moon for around 100 million years after the it formed.

The analysis, published in the journal Science Advances, used a technique called secondary ion mass spectrometry (SIMS) to study volcanic glasses returned from the Apollo 15 and 17 missions, which are thought to represent some of the most primitive volcanic material on the Moon. The study looked specifically at sulfur isotope composition, which can reveal details about the chemical evolution of lavas from generation, transport and eruption.

"For many years it appeared as though the lunar basaltic rock samples analyzed had a very limited variation in sulfur isotope ratios," said Alberto Saal, a geology professor at Brown University and study co-author. "That would suggest that the interior of the Moon has a basically homogeneous sulfur isotopic composition.

On Feb. 22, 1906, German astrophotographer Max Wolf helped reshape our understanding of the solar system. Again.

Born in 1863, Wolf had a habit of dramatically altering the astronomy landscape. Something of a prodigy, he discovered his first comet at only 21 years old. Then in 1890, he boldly declared that he planned to use wide-field photography in his quest to discover new asteroids, which would make him the first to do so. Two years later, Wolf had found 18 new asteroids. He later became the first person to use the "stereo comparator," a View-Master-like device that showed two photographs of the sky at once so that moving asteroids appeared to pop out from the starry background.