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

To see this, recall the definition of angular momentum: Kepler's second law states that the area swept out by the line connecting the satellite to the Earth's center over a given time Δt is a constant ...

“The three previously known planets that orbit the star Kepler-51 are about the size of Saturn but only a few times the mass of Earth, resulting in a density like cotton candy.” What makes the ...

"Kepler-51e has an orbit slightly larger than Venus and is just inside the star's habitable zone, so a lot more could be going on beyond that distance if we take the time to look," Libby-Roberts said.