Hubble Reveals A ‘Red Dot Surprise’ From The Distant Universe

ESA/Hubble & NASA, B. Frye

NASA’s Hubble Space Telescope, currently celebrating its 30th anniversary, still churns out novel discoveries.

HUDF09 and HXDF12 teams / E. Siegel (processing)

By peering into the distant Universe, Hubble reveals galaxies from across cosmic time.

NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)

However, even with phenomenally deep views, most galaxies still remain undiscovered.

NASA, ESA, and Z. Levay, F. Summers (STScI)

Light spreads out as distance increases, rendering the earliest galaxies too faint for most observatories.

E. Siegel / Beyond the Galaxy

Additionally, the Universe’s expansion stretches the light’s wavelength, shifting it out of the visible range.

Rob Knop

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.

NASA, ESA, and E. Rivera-Thorsen (Institute of Theoretical Astrophysics Oslo, Norway)

This phenomenon — strong gravitational lensing — reveals objects otherwise too faint and distant to be seen.

STScI/NASA/CATS Team/R. Livermore (UT Austin)

A decade ago, the Herschel (infrared) and Planck (microwave) observatories combined to identify lensed galaxy candidates.

N. Nesvadba et al. (2016), arXiv:1610.01169

Follow-up observations, performed with Hubble, at last revealed their details.

Brenda L. Frye et al. (2019) ApJ, 871 51

Here, a background galaxy — PLCK G045.1+61.1 — appears as multiple red dots, lensed by a massive foreground cluster.

ESA/Hubble & NASA, B. Frye

It’s a single star-forming galaxy, appearing only 1.9 billion years after the Big Bang.

ESA/Hubble & NASA, B. Frye

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.

NASA / JWST and HST teams

Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more. Continue reading at Forbes