News Science & Society Trump’s ‘Golden Dome’ plan has a major obstacle: Physics The proposed missile defense system has many scientists expressing skepticism Posters depict a conceptual illustration of a planned Golden Dome missile defense system during a news conference at the White House. Mark Schiefelbein/AP photo By Emily Conover 5 minutes ago In sports, the best offense is often a good defense. It’s not clear if the same applies in nuclear war. In the face of nuclear threats from adversaries like Russia, China and North Korea, some politicians are clamoring for a system to reliably protect the United States from incoming missiles. That’s the aim of President Donald Trump’s plan for a next-generation missile defense system, dubbed the “Golden Dome.” Trump announced on May 20 that an architecture had been selected and that the system would be operational before the end of his term, at a cost of $175 billion. But some scientists suggest that implementing such a system, as called for by a January executive order, would be daunting. Sign up for our newsletter We summarize the week's scientific breakthroughs every Thursday.