Over the coming weeks we will feature, in no particular order, each of the final 16 selected images and winners will be announced by Royal Museums Greenwich on 17 September. The winning images are to be showcased at the Royal Observatory Greenwich in an exhibition opening 18 September.
The lightest few chemical elements formed minutes after the Big Bang. Most heavier elements in the periodic table are created by stars, either from internal nuclear fusion or in catastrophic explosions. New observations of a dwarf galaxy discovered last year show that the heaviest elements, such as gold and lead, are likely left over from rare collisions between two neutron stars.
Two black holes in nearby galaxies have been observed in X-rays by ESA’s XMM-Newton space observatory devouring their companion stars at a rate exceeding classically understood limits, and in the process, kicking out matter into surrounding space at astonishing speeds of around a quarter the speed of light.
An international team of researchers have used the W. M. Keck Observatory to confirm the existence of the most diffuse class of galaxies known in the universe. These Ultra Diffuse Galaxies (UDGs) are nearly as wide as our own Milky Way galaxy — about 60,000 light-years — yet harbour only one percent as many stars.