The stars trace an impossible circle in the night sky

This photo isn't real, and not just because it's been squished. The circles up there are star trails completing a full orbit through the sky. That's never been photographed before...and you'll need to head to the Poles to do it.

Time-lapse photography allows us to see these star trails blaze across the sky as they move relative to Earth, but a complete circuit like this couldn't be captured above the Austrian sky as it has in this digitally altered image by Peter Wienerroither of the University of Vienna. You can see the uncompressed image below. The problem with photographing a full 360-degree star trail is that that would take 24 hours, and the Sun would inevitably rise and blot out that part of the image.

The stars trace an impossible circle in the night sky

That's led Walter Lewin, physics professor emeritus at MIT, to pose a challenge to astrophotographers to be the first to create an actual single-exposure time-lapse image of 360-degree star trails. Of course, the only possible way to do that is to head to a part of the Earth where the night lasts at least 24 hours, which means braving the winters above the Arctic and Antarctic Circles.

As such, we may just want to stick with these digital creations for the time being, in which the various stars trace beautiful (albeit doctored) concentric circles in the night sky. Since we're in the northern hemisphere, the center of the circles is the North Celestial Pole. In turn, that means the north star Polaris is the bright innermost circle moving around the celestial pole.

Via NASA.