Inner planets Venus and Mercury can never wander far from the Sun in Earth's sky. This week you've probably seen them both gathered near the western horizon just after sunset, a close conjunction of bright celestial beacons in the fading twilight. The pair are framed in this early evening skyview captured on January 13 from the ruins of Szarvasko Castle in northwestern Hungary.
According to MSL scientists based at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., the ball isn't as big as it looks — it's approximately one centimeter wide. Their explanation is that it is most likely something known as a "concretion." Other examples of concretions have been found on the Martian surface before — take, for example, the tiny haematite concretions, or "blueberries", observed by Mars rover Opportunity in 2004 — and they were created during sedimentary rock formation when Mars was abundant in liquid water many millions of years ago.
But this star, called HD 34989 (among other alphanumeric designations) is special. For one thing, it's massive, probably 10 times the mass of our Sun. It's also incredibly luminous, shining 15,000 times brighter than the Sun. Put that in the center of our solar system, and the global warming we're experiencing now would seem like the deep freeze. Happily, it's over a thousand light years away.