Sometimes we get alerts from different mission teams for reasons we can’t totally identify. In this case, the Chandra X-ray Observatory released a really cool image related to a research paper that came out back in 2016. We’re not quite sure why, but we’re talking about this image release because the science is sufficiently cool anyway. This show wasn’t around back then after all, and the image is newly processed.

So what is this weird set of rings? It turns out, in some cases, we can actually see light traveling through space. In sci-fi movies, you often see pulses of light moving through space, and that doesn’t really work because light moves way too fast to be captured on film or be seen by our eyes.

But if something in space pulses light, we can sometimes see that pulse, and in this particular image, we are seeing multiple pulses. In the center of these circles, there is a black hole that formed from a dying star. This black hole isn’t alone, and its companion star sometimes causes flares of X-ray light to go radiating through space. As the light moves out in spheres, it periodically collides with dust and other material that causes the light to scatter in all directions, including back toward us. This is just like what happens when a sunbeam encounters dust or smoke, and you can suddenly see where the sunbeam is.

Over time, these rings will appear to expand as the shells of light move away from the black hole and its companion, and part of a larger and larger sphere of light is reflected back at us. The science behind this isn’t that different from sound waves echoing off surfaces, and these are called light echoes.

This awesome image and its light echoes tell us a lot of cool things. First off, it literally illuminates dust we normally wouldn’t see and lets researchers measure unexpected things like the dust is made of graphite and silicate grains. The thickness of the rings we see also lets us know how long each pulse of light lasted, and the separations between rings let us figure out how long there was between flares.

Sometimes, it turns out, an image – taken by many telescopes and combined in complex ways – is worth way more than a thousand words.

More Information

CXO press release

“A Joint Chandra and Swift View of the 2015 X-ray Dust-Scattering Echo of V404 Cygni,” S. Heinz et al., 2016 June 27, The Astrophysical Journal