Keep your eye on the ball” is a motto for many athletes—and for astronomers trying to find Earth-threatening space rocks ...

It moves in a weakly hyperbolic orbit, which means that it is likely to pass through the solar system only once. Earlier we wrote about the second moon rising over the Earth for several weeks.

Instead, its orbit would have been hyperbolic — i.e. not closed around the sun — and it would have come from somewhere beyond ...