Category Astronomy/Space

Meteorites such as these carbonaceous chondrites are thought to have delivered water to the Earth–but an outstanding question is when. A new study points to the early incorporation of water in the growing Earth. Credit: Image courtesy Nicolas Dauphas

New measurements of lunar rocks suggest different story about Earth’s early days. Cosmo-chemists have performed the largest study to date of oxygen isotopes in lunar rocks, and found a small but measurable difference in the makeup of the moon and Earth. The research proposes that Earth acquired the majority of its water during the main stage of its growth – which counters a popular theory.

The most widely accepted theory of the origin of the Moon speculates that a giant object smashed into the proto-Earth at just enough velocity that part of b...

This ancient stellar jewelry box, a globular cluster called NGC 6397, glitters with the light from hundreds of thousands of stars. Credit: NASA, ESA, and T. Brown and S. Casertano (STScI) ; Acknowledgement: NASA, ESA, and J. Anderson (STScI)

Astronomers using NASA’s Hubble Space Telescope have for the first time precisely measured the distance to one of the oldest objects after the big bang. This new, refined distance yardstick provides an independent estimate for the age of the universe. The new measurement also will help astronomers improve models of stellar evolution. Star clusters are the key ingredient in stellar models because the stars in each grouping are at the same distance, have the same age, and have the same chemical composition...

Montage showing very high energy gamma ray sources in the Milky Way, seen above the HESS telescopes in Namibia. Credit: © F. Acero, / Map of gamma ray sources / © HESS collaboration

The HESS international collaboration, to which CNRS and CEA contribute, has published the results of 15 years of gamma ray observations of the Milky Way. Its telescopes installed in Namibia have studied populations of pulsar wind nebulae and supernova remnants, as well as microquasars, never before detected in gamma rays. These studies are supplemented by precise measurements such as those of the diffuse emission at the center of our Galaxy. The entire set of data will henceforth serve as a reference for the international scientific community...