But it may still be a galaxy. This sparkling field is Abell 2125, a galaxy cluster located 3
billion light-years away from us in the Ursa Minor constellation. Each golden yellow dot you see
is an individual galaxy, captured in visible light by the Kitt Peak National Observatory. The
purple dots and haze are gas clouds seen in X-ray light by @NASAChandraXray. X-rays are not part
of the visible light spectrum, so they've been translated into color we can see in this image.
It takes billions of years to build a massive galaxy cluster like Abell 2125, which may contain
thousands of galaxies. Since it's so far away, this cluster also gives us insight into the early
stages of galaxy cluster development, as well as the effects on galaxies within it. For example,
data from Chandra, @NASAHubble, and the Very Large Array show that several galaxies in Abell 2125
are being stripped of their gas as they fall through hot, high-pressure clouds.
Image description: This entire image is covered with purple and gold dots. Slightly above center
is
the largest and brightest dot, a galaxy with four diffraction spikes. Throughout the image, but
especially at upper left and bottom right, are purple clouds of gas that you can see through.