Astronomers have made the first accurate measurement of the abundance of oxygen in a distant galaxy. Oxygen is created inside stars and released into interstellar gas when stars die. Quantifying the amount of oxygen, the third-most abundant chemical element in the universe, is key to understanding how matter cycles in and out of galaxies.
Scientists with NASA’s Dawn mission have identified permanently shadowed regions on the northern hemisphere of dwarf planet Ceres. Most of these areas likely have been cold enough to trap water ice for a billion years, suggesting that ice deposits could exist there now. These permanently shadowed regions could be colder than those on Mercury or the Moon.
The Moon was formed by a violent, head-on collision between the early Earth and a “planetary embryo” called Theia (pronounced THAY-eh) approximately 100 million years after the Earth formed, UCLA scientists reveal. This new research also refutes the work of a team of German scientists who, in 2014, reported that the Moon also has its own unique ratio of oxygen isotopes, different from Earth’s.