Sub-Neptunes, planets ranging in size between Earth and Neptune, are the most abundant type of exoplanets discovered to date. However, their nature remains enigmatic, as no such planets exist in our Solar System. Sub-Neptunes are hypothesized to be either bloated terrestrial planets (“super-Earths”), miniature giant planets (“mini-Neptunes”), or perhaps something ...
In a remarkable public lecture in 1920, Arthur Eddington speculated that fusion might become the ultimate long-term energy source. More than a century later, the world is approaching a milestone: generating electricity from fusion for the first time. The National Academies have recommended that “the Department of Energy and the ...
