Astronomy Picture of the Day · May 21, 2026

A Collision of Galaxy Clusters

The Astronomy Picture of the Day for May 21, 2026 is “A Collision of Galaxy Clusters,” an image. It is credited to Image Credit: X-ray: NASA / CXC / CfA / C. Watson et al. ; Optical: PanSTARRS ; Image Processing: NASA / CXC / SAO / N. Wolk and P. Edmonds Text: Cecilia Chirenti ( NASA GSFC , UMCP , CRESST II ). The original explanation runs about 168 words.

On a dark background, galaxies are shown as fuzzy white dots. A bright blue spiral expands from the center. Clicking on the picture will download the highest resolution version available. — Credit: Image Credit: X-ray: NASA / CXC / CfA / C. Watson et al. ; Optical: PanSTARRS ; Image Processing: NASA / CXC / SAO / N. Wolk and P. Edmonds Text: Cecilia Chirenti ( NASA GSFC , UMCP , CRESST II ) Shown from science.nasa.gov. Not hosted by OpenOrbit.

From the explanation

“This big beautiful spiral shines in X-ray light . It is about 20 times larger than our Galaxy .”

— APOD editors, May 21, 2026

Read the full explanation on science.nasa.gov

At a glance

Date: May 21, 2026
Type: Image
Credit: Credit: Image Credit: X-ray: NASA / CXC / CfA / C. Watson et al. ; Optical: PanSTARRS ; Image Processing: NASA / CXC / SAO / N. Wolk and P. Edmonds Text: Cecilia Chirenti ( NASA GSFC , UMCP , CRESST II )
Copyright: No copyright notice on the entry. Check the credited institution’s own usage rules before reusing it.
Explanation length: About 168 words