This image composite combines the best Earth image with the best Moon image from four sets of images acquired on November 20, 2016, by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter (MRO).
MRO’s HiRISE camera snapped the component images from a distance of 127 million miles (205 million km).
The images were acquired for calibration of HiRISE data, since the spectral reflectance of the Moon’s near side is very well known.
For presentation, the exposures were processed separately to optimize detail visible on both Earth and its only natural satellite.
The Moon is much darker than Earth and would barely be visible if shown at the same brightness scale as Earth.
The combined view retains the correct sizes and positions of the two bodies relative to each other.
The distance between our planet and the Moon is about 30 times the diameter of Earth.
Earth and the Moon appear closer than they actually are in the composite image because the observation was planned for a time at which the Moon was almost directly behind Earth, from Mars’ point of view, to see the Earth-facing side of the Moon.
HiRISE takes images in three wavelength bands: infrared, red, and blue-green.
These are displayed here as red, green, and blue, respectively.
This is similar to Landsat images in which vegetation appears red.
The reddish blob in the middle of the Earth image is Australia.
Southeast Asia appears as the reddish area — due to vegetation — near the top.
Antarctica is the bright blob at bottom-left.
Other bright areas are clouds.