A Mars scientist shares the inside story of the NASA Curiosity rover's poignant first photo of Earth and Mars moon Phobos together in the twilight sky.

It is the first time ever the two have been captured together from the surface of Mars. NASA's Curiosity Mars rover used its Mast Camera, or Mastcam, to capture the view of Earth setting while Phobos is rising.

In an out-of-this-world first, Earth and Phobos have been photographed together in the sky by NASA’s Curiosity. The rover has previously snapped this moon and its companion Deimos, including in a beautiful eclipse,