Dark force (New Scientist)
Dark matter is the unseen stuff that sculpts galaxies and clusters of galaxies. Its existence is inferred from its gravitational effects only, and it is "dark" not only in giving off no light but in being mysterious. But astronomers keep trying, and models of dark matter keep changing. The earlier model was of a gas of dark particles that had no effect on each other besides gravity. Now, observations of colliding clusters of galaxies indicate that dark matter does interact with itself somehow, the particles bouncing off each other, or attracting or repelling. The force they exert on each other is called, of course, "dark force." If this works out, it will be a new sector of physics, and a whole new force of nature is always a Big Deal.
Apophis (Discover Magazine)
Apophis is an asteroid named after one of the nastiest demons in Egyptian mythology, the serpent of night that tries to keep the sun from rising. It has such an inauspicious name because it will come uncomfortably close to Earth (though the chance of its hitting is under one in 7 million). For further discomfort, they've just re-appraised its size to 20% bigger than before.
Pause in global warming (New Scientist)
According to Britain's meteorology office, global warming will slow over the next five years. But it's only a pause. And only for the air. The sea is still warming. And the long-term forecast for the century remains unchanged. The pause is because various natural cycles, such as El Nino, have ganged up to counter the warming trend, for a bit.