Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2025 December 24
A panel of six images shows a red dot in the center
of each image. The instrument that took the image is listed
on each image, along with a z number that is the cosmological
redshift.
Please see the explanation for more detailed information.

Mystery: Little Red Dots in the Early Universe
Image Credit: NASA, ESA, CSA, STScI, JWST; Dale Kocevski (Colby College)

Explanation: What are these little red dots (LRDs)? Nobody knows. Discovered only last year, hundreds of LRDs have now been found by the James Webb Space Telescope in the early universe. Although extremely faint, LRDs are now frequently identified in deep observations made for other purposes. A wide-ranging debate is raging about what LRDs may be and what importance they may have. Possible origin hypotheses include accreting supermassive black holes inside clouds of gas and dust, bursts of star formation in young dust-reddened galaxies, and dark matter powered gas clouds. The highlighted images show six nearly featureless LRDs listed under the JWST program that found them, and z, a distance indicator called cosmological redshift. Additionally, searches are underway in our nearby universe to try to find whatever previous LRDs might have become today.

Tomorrow's picture: open space


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