Missing Lithium


The globular star cluster Messier 54Most of the light chemical element lithium now present in the Universe was produced along with hydrogen and helium during the Big Bang but in much smaller quantities. Astronomers have calculated how much lithium they expect to find in the early Universe and from this work out how much they should see in old stars. But the calculations don’t match the observed values. There is about one-third of lithium in stars that we expect to see in our galaxy, The Milky Way.

This new image from the VLT Survey Telescope at ESO’s Paranal Observatory the globular cluster Messier 54, a star cluster that doesn’t belong to the Milky Way but is part of a small satellite galaxy, the Sagittarius Dwarf Galaxy. A team of astronomers has used the VLT to measure how much lithium there is in a selection of stars in Messier 54. They find that the levels are close to those in the Milky Way. So, whatever it is that got rid of the lithium seems not to be specific to the Milky Way.

Image Credit: ESO

A Comet’s Terrain Map


Rosetta Terrain MapThis map of the view looking toward the “belly” and part of the “head” of comet 67P/Churyumov-Gerasimenko is divided into several regions of differing types of terrain.

Based on analysis of images of the comet’s surface taken by OSIRIS, Rosetta‘s scientific imaging system, the mission science team has defined several different regions, each of which has a distinctive physical appearance.

Image Credit: ESA

Solar Flare


An active region on the Sun almost directly aimed at Earth erupted with an X 1.6 flare (the most powerful class) on 10 September, 2014. There was a coronal mass ejection associated with the event. The flare lasted longer than usual and sent out a burst of radiation into space. The time-laps movie below shows the bright flare and the ensuing coils of magnetic loops flickering over a period of roughly five hours. The images used to create the movie were taken in a wavelength of extreme ultraviolet light by the Solar Dynamics Observatory.

Video Credit: NASA.