Strange observations of galaxies challenge ideas about dark matter

A new look at how light bends in the universe could point to an alternative theory of gravity

Streaks around the galaxy cluster Abell 370 reveal more distant galaxies whose light has been bent and distorted by an effect called gravitational lensing.

As seen by the Hubble Space Telescope, the galaxy cluster Abell 370 reveals telltale streaks of light from more distant galaxies that have had their light bent and distorted by an effect called gravitational lensing.

NASA, ESA, and J. Lotz and the HFF Team/STScI

Head-scratching observations of distant galaxies are challenging cosmologists’ dominant ideas about the universe, potentially leading to the implication that the strange substance called dark matter doesn’t exist.