US reactors reach nuclear milestone as China eyes Nvidia chips

Four nuclear reactors in the US reached criticality by July 4, surpassing a Trump administration goal for three new microreactors to achieve the milestone by the nation’s 250th birthday. Criticality means a reactor can sustain a chain reaction, marking progress for nuclear technologies amid rising demand for electricity and emissions-free energy sources, but it does not mean a reactor is ready to supply the grid.

China is preparing to let leading AI companies including Alibaba, ByteDance, and DeepSeek buy Nvidia H200 chips, after previously withholding approval despite US authorization. NATO is also developing a defensive network using sensors, drones, satellites, and AI to detect Russian attackers, while researchers are exploring whether dimming the sun could reduce the risks from future El Niños by cooling the ocean.

Other developments include Meta patenting an AI device designed to record users and analyze emotions for workout plans, chipmakers stacking transistors as Moore’s Law slows, and Ivy League students suspected of AI cheating seeing scores fall in person from 96% all the way down to 48%. Additional items cover parents’ phone use and child attachment, shoebox-sized detector satellites for sensing nuclear bombs in space, and a World Cup match that sent Google Search traffic to a new record.