: Gran Telescopio Canarias (GTC) / Gabriel Pérez (IAC))

Although we’ve now firmly entered the JWST era in astronomy, our deepest views of the faintest objects of all still come courtesy of the Hubble Space Telescope. Now working in its 35th year since launch, Hubble has spent more time viewing certain specific, dedicated regions of sky than any observatory ever, achieving unprecedented depths in the process. The deepest views of the Universe ever remain the , with a cumulative total of 11 days of observing time (across all wavelengths of light), and a portion of the Ultra Deep Field that was cumulatively imaged for roughly twice as long: the .

Even though JWST has also viewed this region, the shorter observing times mean that, in many ways, Hubble’s views are more sensitive to fainter signals, particularly at optical (visible light) wavelengths. However, there’s something that’s a little bit peculiar about the bright, massive galaxies that appear in these Hubble images: it’s as though their light abruptly stops at a particular edge for each galaxy, rather than diffusely continuing the way we see light continuing within…