Peering through a giant cosmic magnifying glass, NASA's Hubble Space Telescope has spotted one of the farthest, faintest, and smallest galaxies ever seen. The diminutive object is estimated to be more than 13 billion light-years away. This new detection is considered one of the most reliable distance measurements of a galaxy that existed in the early universe, said the Hubble researchers. Hubble detected the galaxy due to the lensing power of the mammoth galaxy cluster Abell 2744, nicknamed Pandora's Cluster. The cluster is so massive that its powerful gravity bends the light from galaxies far behind it, making the background objects appear larger and brighter in a phenomenon called gravitational lensing.
The Kuiper Belt is a vast disk of icy debris left over from our Sun's formation 4.6 billion years ago. Kuiper Belt objects (KBOs) are a unique class of solar-system body that has never been visited by interplanetary spacecraft. They contain well-preserved clues to the origin of our solar system. NASA's New Horizons probe will fly by Pluto in mid-2015 and then continue across the Kuiper Belt on its way toward interstellar space. The Hubble Space Telescope was used to do a deep sky survey to identify KBOs that the New Horizons spacecraft could potentially visit on its outbound trajectory. The deep sky survey was successful, and Hubble found targetable KBOs for New Horizons.
Astrophysics: How tiny galaxies form stars
Nature 514, 7522 (2014). doi:10.1038/514310a
Authors: Bruce Elmegreen
Observations of two faint galaxies with a low abundance of elements heavier than helium show that the galaxies have an efficiency of star formation less than one-tenth of that of the Milky Way and similar galaxies. See Letter p.335
Inefficient star formation in extremely metal poor galaxies
Nature 514, 7522 (2014). doi:10.1038/nature13820
Authors: Yong Shi, Lee Armus, George Helou, Sabrina Stierwalt, Yu Gao, Junzhi Wang, Zhi-Yu Zhang & Qiusheng Gu
The first galaxies contain stars born out of gas with few or no ‘metals’ (that is, elements heavier than helium). The lack of metals is expected to inhibit efficient gas cooling and star formation, but this effect has yet to be observed in galaxies with an oxygen abundance (relative to hydrogen) below a tenth of that of the Sun. Extremely metal poor nearby galaxies may be our best local laboratories for studying in detail the conditions that prevailed in low metallicity galaxies at early epochs. Carbon monoxide emission is unreliable as a tracer of gas at low metallicities, and while dust has been used to trace gas in low-metallicity galaxies, low spatial resolution in the far-infrared has typically led to large uncertainties. Here we report spatially resolved infrared observations of two galaxies with oxygen abundances below ten per cent of the solar value, and show that stars formed very inefficiently in seven star-forming clumps in these galaxies. The efficiencies are less than a tenth of those found in normal, metal rich galaxies today, suggesting that star formation may have been very inefficient in the early Universe.
Dust to dust
Nature 514, 7522 (2014). doi:10.1038/514273b
What lessons can be learned from the presentation of the gravitational-waves story?