Monday, 28 March 2011
Tuesday, 15 March 2011
Monday, 14 March 2011
Sunday, 13 March 2011
Wednesday, 9 March 2011
This image shows the afterglow of GRB 090423 (red source in the centre) and was created from images taken in the z, Y and J filters at Gemini-South and VLT (credit: A. J. Levan).
“This explosion provides an unprecedented look at an era when the Universe was very young and also was undergoing drastic changes. The primal cosmic darkness was being pierced by the light of the first stars and the first galaxies were beginning to form. The star that exploded in this event was a member of one of these earliest generations of stars,” said Dale Frail of the National Radio Astronomy Observatory.
The Thirteen Towers of Chankillo run from north to south along the ridge of a low hill within the site; they are relatively well-preserved and each has a pair of inset staircases leading to the summit.
The rectangular structures, between 75 and 125 square metres (807-1,345 sq ft) in size, are regularly spaced - forming a "toothed" horizon with narrow gaps at regular intervals.
About 230m (750ft) to the east and west are what scientists believe to be two observation points. From these vantages, the 300m- (1,000ft-) long spread of the towers along the horizon corresponds very closely to the rising and setting positions of the Sun over the year.