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 ...

There's no shortage of round celestial objects in our universe. Planets, moons and stars all exhibit lovely spherical shapes. But astronomers recently spotted a mysteriously circular orb deep in the ...

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 ...