In the most famous pictures of Robert Smithson’s monumental earthwork “Spiral Jetty”, the craggy coil of black basalt and limestone protrudes through the surface of the Great Salt Lake. In many of these photos, the lake takes on a deep red hue thanks to the local plankton. In others, it looks more like a fogged-over mirror after a hot shower. I’d seen both versions during slideshows in undergraduate art history classes, and that’s how I’d pictured it ever since.