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Early observations of the flaring object ASASSN-15lh led astronomers to cast it as the most luminous supernova ever. Now, convincing evidence indicates that this object is not as it seemed. In fact, fitting it into any known box is a challenge.
The detection of a tailed radio galaxy in a galaxy cluster conjoined to a region of diffuse radio emission confirms that radio galaxies provide the energetic electrons needed to explain the origin of this enigmatic emission.
The heated debate on the importance of stellar rotation and age spreads in massive star clusters has just become hotter by throwing stellar variability into the mix.
Atmospheres within the Solar System are known to exhibit seasonal changes. Observations with the Kepler spacecraft hint at analogous periodic weather variations in an exoplanet atmosphere.
This Review gives an overview of some pivotal open questions on planetary formation and evolution, with water as the underlying common theme, and how the planetary and exoplanetary communities can help each other in addressing them.
