A renovated, second-generation fusion reactor in England has achieved first plasma. This reactor and other fusion reactors have long-shot plans to produce energy as early as 2040. The new reactor ...

A new study has revealed the true shape of the diffuse cloud of stars surrounding the disk of our galaxy. For decades, astronomers have thought that this cloud of stars—called the stellar halo—was ...

A:Bodies large enough to be considered planets have enough mass that gravity molds them into a roughly spherical shape. The key word here is roughly — other factors also come into play, such as a ...