What happened
Ukraine fired U.S.-provided long-range missiles into Russia for the first time yesterday, as Russian President Vladimir Putin officially lowered his country's threshold to use nuclear weapons. The U.S. and Europe said they were more concerned about Russia accelerating its hybrid warfare campaign against NATO countries. President Joe Biden, who recently approved Ukraine's use of ATACMS missiles inside Russian territory, also agreed yesterday to provide Kyiv with "nonpersistent" anti-personnel land mines to defend its eastern flank.

Who said what
The U.S. said Ukraine fired seven or eight ATACMS missiles about 70 miles into Russia's Bryansk region early yesterday, hitting an ammunition depot, and Russia shot down two. Ukraine said the missiles destroyed warehouses storing artillery shells, glide bombs, and several kinds of missiles. Russia said it shot down five ATACMS and damaged a sixth.

As Russia threatened retaliation for the U.S. ATACMS, European countries suggested Russia orchestrated the disabling of undersea data cables between Sweden and Lithuania on Sunday and Finland and Germany on Monday. Western officials said Russia also plotted to firebomb U.S.-bound airplanes, sabotage military installations and instigate arson attacks in Europe.

The foreign ministers of Germany, France, Poland, Italy, Spain and the U.K. yesterday jointly condemned "Moscow's escalating hybrid activities against NATO and EU countries." The "likely motive" behind such sabotage is to "spread panic, bind security resources, and increase pressure on Western governments by boosting political parties who are campaigning against the massive aid provided to Ukraine," The Wall Street Journal said.

What next?
The U.S. mines should be "delivered soon," the BBC said. "Russia is attacking Ukrainian lines in the east with waves of troops, regardless of the casualties that they're suffering," one U.S. official told The Washington Post. "These mines were made specifically to combat exactly this."

What happened
An international consortium of scientists studying dark energy said yesterday their three-dimensional map of the universe over 11 billion years suggested the cosmos wasn't steadily expanding, but acting more like Albert Einstein predicted in his 1915 general theory of relativity.

Who said what
Cosmologists since 1998 have theorized that a mysterious invisible force dubbed dark energy was pushing the universe apart at an ever-faster rate. Scientists gathering and studying data from the Dark Energy Spectroscopic Instrument (DESI) at Kitt Peak National Observatory in Arizona found it "may not be an unchangeable force," Reuters said.

"Dark energy seems to be dynamical and weakening," said astrophysicist Mustapha Ishak-Boushaki of the University of Texas at Dallas, a leader of the DESI working group. The "strong hint" that the universe need not be "accelerating forever in its expansion" is the "most important finding since the discovery of cosmic acceleration in 1998." Scientists still don't understand dark energy — believed to make up 68% of the universe, versus just 5% for everything visible and tangle — but the DESI findings that it's "changing or weakening over time" would "upend astronomers' standard cosmological model," The Associated Press said.

What next?
The "new findings aren't definitive," and astronomers need "more data to overturn a theory that seemed to fit together so well" — but "there's a lot riding on the answer," the AP said. If dark energy is constant, the universe will continue to expand, "forever getting colder and emptier," and if it's strengthening, "the universe will expand so speedily that it'll destroy itself in what astronomers call the Big Rip." That wouldn't happen "for billions of years," astrophysicist David Spergel told the AP. "But we'd like to know about it."