This is likely the final photo that NASA's Mars InSight lander will ever send back to Earth. The robot has been snapping pics and gathering data about the Martian environment since landing on the planet in November 2018 — and it's been steadily accumulating dust on its solar panels that entire time. As NASA predicted earlier this year, the layer of debris has finally become too thick for the solar panels to operate. The InSight Twitter account officially said goodbye on December 19th with...