How old are the oldest galaxies? Faint red smudges (circled) on the deepest optical sky image (click to embiggen) ever taken may well be members of the first class of galaxies. Detailed inspection of the Hubble Ultra Deep Field taken by the Hubble Space Telescope found the galaxies and used their distance and abundance to probe the universe when it was but a small fraction of its present age. Analyses indicate that all members of this class of galaxies are dwarf galaxies from which larger modern galaxies must have formed. Some large modern galaxies shine brightly in the colorful foreground. The early dwarf galaxies probably contained energetic stars emitting light that transformed much of the remaining normal matter in the universe from a cold gas to a hot ionized plasma.
Image Credit: NASA/ESA/ASU/CalTech
However, scientists studying this phenomenon are equipped with better tools than in Hubble’s day. Mt. Wilson Observatory is rarely used now due to light pollution, but several 200-inch telescopes have since been built, and a pair of 400-inch telescopes currently operate at Keck Observatory in Mauna Kea, Hawaii. Additionally, a satellite launched in 1990 carries the Hubble Space Telescope , capable of viewing galaxies more than 10 billion light years away. Each of these telescopes is equipped with digital light detectors far more sensitive than Hubble’s photographic plates.Currently, researchers are using another powerful telescope to conduct the Sloan Digital Sky Survey , the largest study of galactic velocities to date. The results of this research may provide some much-needed insight into the future of our universe, continuing Hubble’s goal of understanding our cosmos. However, new findings are likely to spur an additional round of questions, similar to the uproar that followed publication of Hubble’s original 1929 research. “We used to be able to explain what the universe was doing to our students and now we can’t anymore,” said Haynes.