Without a little help from Einstein, we couldn’t have made this discovery.
NASA’s Hubble Space Telescope, currently celebrating its 30th anniversary, still churns out novel discoveries.
By peering into the distant Universe, Hubble reveals galaxies from across cosmic time.
However, even with phenomenally deep views, most galaxies still remain undiscovered.
Light spreads out as distance increases, rendering the earliest galaxies too faint for most observatories.
Additionally, the Universe’s expansion stretches the light’s wavelength, shifting it out of the visible range.
However, Einstein’s idea — of mass curving space — frequently lends a helping hand.
Intervening concentrations of matter between ourselves and a distant object can stretch, distort, and magnify its light.
This phenomenon — strong gravitational lensing — reveals objects otherwise too faint and distant to be seen.
A decade ago, the Herschel (infrared) and Planck (microwave) observatories combined to identify lensed galaxy candidates.
Follow-up observations, performed with Hubble, at last revealed their details.
Here, a background galaxy — PLCK G045.1+61.1 — appears as multiple red dots, lensed by a massive foreground cluster.
It’s a single star-forming galaxy, appearing only 1.9 billion years after the Big Bang.
The stars within are intrinsically blue; the red color arises from cosmic expansion.
Using similar techniques, NASA’s upcoming James Webb Space Telescope will shatter our earliest galaxy records.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.
Ethan Siegel is the author of Beyond the Galaxy and Treknology. You can pre-order his third book, currently in development: the Encyclopaedia Cosmologica.