Faintest galaxies ever seen explain the 'missing link' in the Universe (Synopsis)

"The problem is, you’re trying to find these really faint things, but you’re looking behind these really bright things. The brightest galaxies in the universe are in clusters, and those cluster galaxies are blocking the background galaxies we’re trying to observe." -Rachael Livermore

One of the biggest puzzles in science is exactly how the Universe became transparent to visible light. Neutral atoms -- cosmic dust -- blocks visible light, and yet before there were stars, that’s all we had. According to theory, it should be large numbers of small, faint, ultra-distant galaxies that made it transparent, but they’ve never been seen.

The reionization and star-formation history of our Universe, where reionization was driven by these faint, early but theoretically numerous galaxies. At last, thanks to Livermore's work, we're discovering them. Image credit: NASA / S.G. Djorgovski & Digital Media Center / Caltech. The reionization and star-formation history of our Universe, where reionization was driven by these faint, early but theoretically numerous galaxies. At last, thanks to Livermore's work, we're discovering them. Image credit: NASA / S.G. Djorgovski & Digital Media Center / Caltech.

However, thanks to the combined power of the Hubble Space Telescope, gravitational lensing and a new foreground light-removal technique, galaxies 100 times fainter thank the ones visible in the Hubble eXtreme Deep Field -- the longest-exposure image ever -- have now been revealed. These galaxies, seen in two Frontier Fields’ clusters so far, are the ‘missing link’ needed to explain reionization.

The ultra-distant, lensed galaxy candidate, MACS0647-JD, appears magnified and in three disparate locations thanks to the incredible gravity of the gravitational lens of the foreground cluster, MACS J0647. Image credit: NASA, ESA, M. Postman and D. Coe (STScI), and the CLASH Team. The ultra-distant, lensed galaxy candidate, MACS0647-JD, appears magnified and in three disparate locations thanks to the incredible gravity of the gravitational lens of the foreground cluster, MACS J0647. Image credit: NASA, ESA, M. Postman and D. Coe (STScI), and the CLASH Team.

Come get the full, stunning story in visuals and no more than 200 words on today’s Mostly Mute Monday!

More like this

So far indeed. It is blobbish and small, but interesting. From NASA: PASADENA, Calif. - By combining the power of NASA's Hubble and Spitzer space telescopes and one of nature's own natural "zoom lenses" in space, astronomers have set a new record for finding the most distant galaxy seen in the…
“Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will…
"The discovery that young galaxies are so unexpectedly bright--if you look for this distinctive green light--will dramatically change and improve the way that we study Galaxy formation throughout the history of the Universe." -Matthew Malkan Galaxies come in many different colors today: white, blue…
"Now the world has gone to bed, Darkness won't engulf my head, I can see by infrared, How I hate the night." -Douglas Adams The Hubble Space Telescope is an amazing piece of equipment, and has seen more distant stars and galaxies than any telescope before or since. Earlier this year, it broke its…

I somehow feel JWST is going to show us more of the same, younger galactic configurations. Eventually, we will have to learn what will be needed to view beyond the first moments of starlight.

Tease! I thought you were actually going to explain reionization (i.e. the theories and observations that came out of the technique) Oh well, maybe another post.