A certain class of massive galaxies in the early universe lived fast and died young. By "died" astronomers mean that the galaxies had completed building stars just 3 billion years after the big bang. By contrast, our 12-billion-year-old Milky Way galaxy continues making stars today. When star formation stops, the aging stellar population looks redder in the star-forming galaxies that are more bluish. The nickname for the essentially "burned-out" galaxies is "red and dead."
Astrophysics: Portrait of a dynamic neighbour
Nature 505, 7485 (2014). doi:10.1038/505625a
Authors: Adam P. Showman
Brown dwarfs are celestial objects that lack the mass to become fully fledged stars. High-resolution maps of one such object add to the evidence that these exotic worlds have highly dynamic weather and climate. See Letter p.654
Solar System evolution from compositional mapping of the asteroid belt
Nature 505, 7485 (2014). doi:10.1038/nature12908
Authors: F. E. DeMeo & B. Carry
Advances in the discovery and characterization of asteroids over the past decade have revealed an unanticipated underlying structure that points to a dramatic early history of the inner Solar System. The asteroids in the main asteroid belt have been discovered to be more compositionally diverse with size and distance from the Sun than had previously been known. This implies substantial mixing through processes such as planetary migration and the subsequent dynamical processes.
A global cloud map of the nearest known brown dwarf
Nature 505, 7485 (2014). doi:10.1038/nature12955
Authors: I. J. M. Crossfield, B. Biller, J. E. Schlieder, N. R. Deacon, M. Bonnefoy, D. Homeier, F. Allard, E. Buenzli, Th. Henning, W. Brandner, B. Goldman & T. Kopytova
Brown dwarfs—substellar bodies more massive than planets but not massive enough to initiate the sustained hydrogen fusion that powers self-luminous stars—are born hot and slowly cool as they age. As they cool below about 2,300 kelvin, liquid or crystalline particles composed of calcium aluminates, silicates and iron condense into atmospheric ‘dust’, which disappears at still cooler temperatures (around 1,300 kelvin). Models to explain this dust dispersal include both an abrupt sinking of the entire cloud deck into the deep, unobservable atmosphere and breakup of the cloud into scattered patches (as seen on Jupiter and Saturn). However, hitherto observations of brown dwarfs have been limited to globally integrated measurements, which can reveal surface inhomogeneities but cannot unambiguously resolve surface features. Here we report a two-dimensional map of a brown dwarf’s surface that allows identification of large-scale bright and dark features, indicative of patchy clouds. Monitoring suggests that the characteristic timescale for the evolution of global weather patterns is approximately one day.
US struggles to offload telescopes
Nature 505, 7485 (2014). http://www.nature.com/doifinder/10.1038/505594a
Author: Alexandra Witze
West Virginia radio observatory seeks money from partners to fend off closure by the National Science Foundation.