|Edwin Hubble at 100-Inch|
Ever since, astronomers have struggled to trace the evolution of galaxies back through space-time—not just hundreds of millions of light-years but billions. For decades, all that astronomers could say with surety were that distant galaxies and clusters looked a bit “bluer,” a sign of heightened star formation as hoards of young, massive stars, flush with energy, put out more blue light.
Quasars, the brilliant cores of newborn galaxies, had long been sighted at great distances, but astronomers questioned whether they could truly understand the early universe by studying only its most active members.
But thanks to key technological breakthroughs over the last two decades—among them, the Hubble Space Telescope, the opening of giant telescopes in Hawaii and South America, and advances in telescopic detectors—more typical primordial galaxies are now being found, and at greater and greater distances.
|UDFy-38135539 (circled in red) lurks within the Ultra Deep Field|
The current record holder was recently discovered by a European team of astronomers using the European Southern Observatory’s Very Large Telescope (VLT) in Chile. It’s but a speck in the image, but a sensitive spectrograph allowed the observers to peg its distance. It’s more than 13 billion light-years from Earth and has been christened UDFy-38135539. That’s a mouthful for us but helpful to astronomers: the UDF stands for Ultra Deep Field (a region located in the southern-hemisphere constellation Fornax that was first closely imaged by the Hubble Telescope) and the number pegs its precise position on the sky.