A massive galaxy has been discovered early in the history of the universe, a time when such mature galaxies were not thought to exist. The find calls into question current thinking on galaxy formation.
The galaxy, HUDF-JD2, is one of the most distant ever observed. Its light, captured by the Hubble and Spitzer space telescopes, began its journey towards Earth a mere 800 million years after the Big Bang.
"That's a very short timescale to form such a massive galaxy," says Bahram Mobasher, an astronomer with the European Space Agency and the Space Telescope Science Institute in Baltimore, Maryland, US.
The time when stars and galaxies first formed is "a holy grail that many people are hunting for in astronomy," says John Huchra, an astronomer with the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US.
IT MIGHT not knock Coldplay or Kanye West off the top of charts, but physicists who say they have cracked the riddle of "singing" sand dunes are compiling a CD of sand music. The team say their new theory allows them to predict the notes that different dunes will make.
Sand dunes in certain parts of the world are notorious for the noises they make as sand avalanches down their sides. Some emit low powerful booms, others sound like drum rolls or galloping horses, and some are even tuneful. These dune songs have been reported to last for up to 15 minutes and can sound as loud as a low-flying aeroplane. Physicists know it is the avalanches that set the grains humming, but the precise mechanism has remained controversial (New Scientist, 18 December 2004, p 8).