The distant cosmos as seen in the infrared
(Phys.org) —At some stage after its birth in the big bang, the universe began to make galaxies. No one knows exactly when, or how, this occurred. For that matter, astronomers do not know how the lineages of our own Milky Way galaxy and its stars trace back to those first galaxies and their first stars, but astronomers have been working hard to find out. The Hubble Space Telescope announced in 1996 that it had stared at apparently dark sky for ten days at optical wavelengths, long enough to acquire a picture of the very distant universe. The resultant image, the Hubble Deep Field (HDF), reveals galaxies that are so far away that they existed when the universe was less than about 5% of its present age of 14 billion years. Since 1996 astronomers have been working to understand exactly what kinds of galaxies these remote objects are, and whether they...