Human eyes have many limitations. For example, blue tones generally look darker compared to other colors because our eyes are less sensitive to blue light. Here is the latest "Blue Marble" image from the NASA satellite Suomi NPP (original image here) converted to physical colors. This image processing technique is used to try to reproduce how Earth really looks like, at least for 'alien eyes' with equal sensitivity to all colors. Note that the blue tones show more oceanic details and the atmosphere layer is more visible. Original image credit: NASA/NOAA/GSFC/Suomi NPP/VIIRS/Norman Kuring.