The agency’s top food official will step in to the role after Dr. Makary privately said he opposed the administration decision to approve flavored vapes.

The slowed pace of grants by the National Science Foundation, under attack from the White House, could put the United States at a disadvantage with China, the scientists warned.

The Pentagon on Friday released online what it called “new, never-before-seen” files, dating back decades, related to unidentified flying objects.

The initial files are murky images that show what could be anything. The government said more would be released on a rolling basis.

President Trump withdrew from the Obama-era nuclear accord in 2018, saying it was the worst deal ever. But Iran responded with an enrichment spree that haunts the negotiations to this day.

First of all, it isn’t dust. It’s Iran’s stockpile of near-bomb-grade uranium, which is stored in large canisters about the size of scuba tanks.

The conversation celebrated a small, but significant, step in an ambitious plan for missions to the moon and Mars that Mr. Trump had set early in his first term.

The launch of Artemis II captured the tenor of the times in a country that can still do big things but seems forever mired in big problems.

The Trump administration is curbing animal experiments in response to shifts in public opinion, technological advances, years of animal rights advocacy and the work of a conservative activist.

It remains to be seen whether the three big nuclear powers are headed into a new arms race, or whether President Trump is trying to spur negotiations on a new accord now that a last Cold War treaty has expired.