Second Light The Most Distant Known Object in the Universe

摘要

As far as we can tell, the Universe began about 13.7 billion years ago with the Big Bang. By the end of the first few minutes, matter had been created, inflation had happened, and the overall properties of the Universe established. Several hundred thousand years later, the Universe had expanded and cooled sufficiently for electrons to combine with protons to form hydrogen atoms. At that time, radiation could stream freely outward, and it is from this time that cosmic microwave background comes. Some hundreds of millions of years later - no one knows for sure how many - the first stars and galaxies began to form. Rychard Bouwens and Garth Illingworth of the University of California-Santa Cruz and their collaborators have now found the most distant known galaxy, at a redshift of z~10 (500 million years after the Big Bang), using data taken by the Hubble Space Telescope over the last two summers, after its latest refurbishment (see the January 27 issue of Nature).