See Mercury at sunset

The timing couldn't be better. Just as NASA's MESSENGER probe is about to enter orbit around Mercury, the innermost planet is popping out of the twilight for its best apparition of 2011.

Super harvest moon to produce rare twilight glow

For the first time in almost 20 years, northern autumn is beginning on the night of a full Moon. The coincidence sets the stage for a "Super Harvest Moon" and a must-see sky show to mark the change of seasons.

Twilight zone at risk from climate change

Life in the ocean's "twilight zone" could decline dramatically due to climate change, new research suggests. The twilight zone (200m to 1,000m deep) gets very little light but is home to a wide variety of organisms and billions ...

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