Much closer to the horizon and a distinct reddish color, the planet Mercury isn’t on most people’s observing lists. In fact, a professional astronomer last year told me it was impossible to ...

New images of the planet Mercury taken by a robotic spacecraft have just been released — and they show the scorched world in fascinating up-close detail. The European Space Agency (ESA ...

Flying 295 km above Mercury, it photographed icy craters, volcanic plains, and the planet's largest impact crater. Mercury reflects two-thirds less light than Earth's Moon, making its surface ...

Each planet takes a different length of time to orbit the sun: Venus, for instance, completes one orbit in 225 days, while Mercury zips around the star in 88 days and Saturn takes 29.4 years to ...