Birth of a galaxy
THANKS to the Bubble Space Telescope, scientists can now actually see ancient galaxies being forI The instrument, unlike earthbound telescopes, can be aimed at galaxies 4 billion light years away. Because le the light that is picked up was emitted 4 billion years ago, it provides a view of the galaxy as it was then.
Astronomers at USA's Carnegie Institution recently saw a galaxy cluster that was formed about 5 billion years ago, a third of the way back to the Big Bang, one of the theories used by scientists to explain the tic birth of the universe. According to the Big Bang theory, the universe evolved about 15 billion years ago Though the cluster contains galaxies that are seen today as elliptical, lens shaped and gardens of spirals astronomers report their proportions were quite different in the past (Science, Vol 258, No 5089). Some 30 per cent of the galaxies were spiral in then, whereas now such galaxies in modern galactic clusters are only 5 per cent.
Scientists postulate spiral galaxies are active star farmers, which burn out after using up all their star forming material.