These images show a pair of galaxies at redshifts 7-7.5, when the universe was only 700 million years old, or only 5% of its current age. The color images are a combination of an exposure in the optical i-band filter (0.8 micron; here in blue), the optical z-band filter (0.9 micron; here in green), and a combined near-infrared J+H band filter (1.1-1.6 micron; here in red). Because of their extreme distance, the sources are only visible in the near-infrared, and therefore appear red in this image. (Image courtesy Ivo Labbé and Rychard Bouwens; click each image for a higher-resolution version.) [return to release]

This figure shows the relation between redshift and the age of the universe. Redshift occurs when light shifts to longer, redder wavelengths as it travels across the ever-expanding universe. More pronounced redshift means the light has been traveling longer, from farther away; therefore the degree of redshift allows astronomers to know how far back in time they are looking.

The two high-redshift galaxies in this study, shown at redshift 7-7.5, are very distant, and their light was emitted when the universe only 700 million years old. The timeline shows several major events in the history of the universe, beginning with the Big Bang and advancing through the haze of the “Dark Ages,” the formation of the first stars and galaxies, and eventually arriving at the present day, with normal galaxies like our Milky Way. The yellow bars next to the two high-redshift galaxies show the time period during which most of their stars formed. These galaxies might be the first in the universe to have formed, shortly after the first stars. (Image courtesy Ivo Labbé; click image for a higher-resolution copy.) [return to release]

This series of images shows two galaxies, dubbed 964 and 1417, which existed 700 million years after the Big Bang. Data from the Spitzer images allowed researchers to calculate their mass, age, distance, and star formation rates, making these the youngest and most distant galaxies for which this information exists.

From left, the first four columns were taken with cameras aboard the Hubble Space Telescope: i775 and z850 were taken in visible light wavelengths with the Advanced Camera for Surveys (ACS), while J110 and H160 were taken in near-infrared wavelengths with the Near Infrared Camera and Multi-Object Spectrograph (NICMOS). The final two columns, 3.6 μm and 4.5 μm, were taken in the mid-infrared with the Infrared Array Camera (IRAC) aboard the Spitzer Space Telescope. (Image from Astrophysical Journal Letters, Vol. 649, p. L67. Copyright 2006 American Astronomical Society, used with permission.) [return to release]