James Webb spots signal from an apparently empty void in space

The James Webb Space Telescope twice detected a lone emission line in a region of the Fornax constellation thought to be empty. The signal could not be matched to any known galaxy and was absent from earlier observations. The authors of a paper in The Astrophysical Journal found no fully satisfactory explanation.

• Observations were made in August and November 2023 at different angles
• One of seven emission detections matched no known galaxy
• The signal is bright enough yet missing from earlier data
• Possible causes: early galaxy, supernova, or a black hole eating a star