One of JWST’s main science goals was to teach us how the Universe grew up to be the way it is today, and one important cosmic mystery to solve was how the Universe came to be transparent to starlight.
Previous studies had shown that the most prominent early JWST galaxies, the big, bright, massive ones, were too rare and too few in number to create enough ultraviolet photons to be responsible.
But a new study, highlighting many gravitationally lensed early, low-mass, but rapidly star-forming galaxies, measured their abundance exquisitely. We’ve found, at last, the main culprit behind cosmic reionization.
