In the Martian sky, the sun appears roughly two-thirds the size it looks from Earth, and at sunset it glows blue rather than red — the same dust particles that make daytime skies pink on Mars scatter shorter wavelengths at dusk in exactly the opposite pattern to our atmosphere

Stand on Mars and watch the Sun go down, and two things would look strange to an Earthling’s eye. The Sun itself would be noticeably smaller, about two-thirds the size it appears from home. And as it sank toward the horizon, it would glow blue, not red. Mars …