NASA Hubble Telescope Finds Missing Oxygen in Dwarf Galaxies

What was announced

NASA released an image from the Hubble Space Telescope showing NGC 4449, a dwarf irregular galaxy. The photo was published on Nov. 2, 2026. The image forms part of a project named the Galaxies Losing Oxygen via Winds (GLOW) study.

Astronomers in the study examined 37 nearby dwarf galaxies. NASA defines dwarf galaxies as small galaxies containing between a few thousand and hundreds of millions of stars. Researchers expected these galaxies to hold the oxygen created by their stars. Instead, observations showed that much of the expected oxygen is missing, with dwarf galaxies retaining only a small fraction of it. Credit for the image includes NASA, ESA, the Hubble Heritage team, and researcher Alessandra Aloisi.

What it means

Stars produce elements such as oxygen throughout their lives. Astronomers generally expect galaxies to retain these elements within their boundaries as stars age and evolve.

Findings from the GLOW study indicate that dwarf galaxies lose most of their oxygen. Gas winds move the oxygen out of the galaxies and into surrounding space. This process alters how astronomers view small stellar systems, showing that dwarf galaxies act as exporters of chemical elements rather than holding onto them. The loss of oxygen demonstrates that galactic winds strongly influence the chemical buildup of smaller galaxies.

What the announcement does not tell us

The report leaves several details unexplained. It does not state the exact percentage of oxygen missing from NGC 4449 or the other 36 galaxies analyzed in the study. NASA also does not explain the specific physical drivers behind the winds pushing the oxygen away.

Furthermore, the announcement does not say when the GLOW study began or if follow-up observations are planned. The document provides no information on whether all 37 galaxies lose oxygen at the same rate.