Light from Distant Galaxies

This image of the Hubble Ultra-Deep Field is part of the deepest infrared image ever taken of the universe. The small blue box outlines the area where astronomers found what may be the most distant galaxy ever seen, 13.2 billion light-years away, meaning its light was emitted just 480 million years after the Big Bang. It is small and very faint and is shown separately in the larger box. Credit: NASA, ESA, Garth Illingworth (UC Santa Cruz), Rychard Bouwens (UC Santa Cruz and Leiden University) and the HUDF09 Team.

Welcome to the companion page to my 365 Days of Astronomy podcast about distant galaxies. The study of the first galaxies is a hot topic in astronomy and cosmology these days.  For the past few years, Hubble and other telescopes have been discovering  younger and more distant galaxies, extending our “view” back to within a few hundred million years of the Big Bang. The question “When did the first galaxies form?” is very close to being answered within a decade or so.  The James Webb Space Telescope will be able to see back to the infant times of the first galaxies, and give us a peek at their births.

The early universe was a busy time, an epoch when the first stars were forming form the materials created in the Big Bang. Naturally, those stars and the materials from which they formed, were pulled together into dense regions by the influence of dark matter. When this started happening and how is something that astronomers are studying now. The light from those early stars and galaxies — first radiated as extremely energetic ultraviolet light — is redshifted and made visible to us in the infrared.  This is why the upcoming James Webb Space Telescope, which is infrared-sensitive, will be so important to astronomers seeking to find the light from the formation of galaxies.  It will be visible mainly in the infrared, and this telescope will have the power to see across more than 13.2 billion light-years to see the earliest events after the Big Bang, when the first stars began to shine, and assemble into the precursors of galaxies called “protogalaxies.”

To learn more about the first galaxies that I discuss in this podcast, point your browser to, a site written by three astronomers whose research regularly takes them out to the earliest epochs of galaxy formation:  Garth Illingworth, Rychard Bouwens, and Dan Magee.

Hubble Space Telescope’s Hubblesite pages have many stunning images of galaxies from across nearly all epochs of cosmic history.  Be sure and spend some time browsing there, too. The infrared-capable Spitzer Space Telescope is also peering back across time and space to study early galaxies. Its findings are expanding our understanding about early galaxy formation and the starbirth bursts that accompany galaxy collisions throughout the cosmos. Stay tuned — the news about the first galaxies is only going to heat up!

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