In a sense, they’re all real, even though they were collected in different ways. The first is a photograph taken by the crew of Apollo 11, on their way to the moon. The second is from the Deep Space Climate Observatory (DSCOVR), from its vantage point at 1,000,000 miles from Earth. The third is a day’s worth of data from NASA’s MODIS instrument, wrapped around a sphere and rendered with a simulated atmosphere.

But what makes a realistic picture? After all, our eyes and brain are reconstructing a sharp, full-color, three-dimensional environment from a tiny amount of information.