The first time I saw this photo on the European Space Agency's XMM-Newton space telescope site I couldn't believe my eyes. It didn't look like any space structure I've seen before. It actually looks like some kind of weird inter-dimensional portal.
Then I read the description and the answer was simple — and actually quite fascinating. What you're looking at is the "reflection patterns off one of the gold-plated spare mirrors" of the telescope:
This image shows the journey that light particles from [supernovas and galaxies] might make on their way to the space telescope's detectors. In this artistic shot patterns are created by light reflected in one of the gold-plated mirrors. XMM-Newton's three telescopes each contain 58 mirrors like this, and are among the most powerful ever developed.
The XMM-Newton has nested one-millimetre-thick mirrors, like "the layers of a leek." According to the ESA, the mirror's shape and position ensure that every X-ray is reflected twice while focusing onto the detector. Beautiful. [ESA]