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1. Secretary of State Antony Blinken canceled a trip to Beijing after a Chinese spy balloon was detected over the U.S.

The cancellation was the culmination of a diplomatic clash that has been unfolding since the high-altitude balloon was detected floating over Montana a few days ago. Pentagon officials said the device was an “intelligence-gathering” airship, while China described it as a civilian balloon that had strayed off course, and said it regretted the “unintended entry” into U.S. airspace. (Here is what we know about the balloon.)

Blinken was scheduled to leave this evening for the trip, which would have been the first visit to China by a U.S. secretary of state since 2018. No new trip has been scheduled, and aides said he would make the visit when conditions were right, after making clear to Chinese officials that the intrusion was “unacceptable and irresponsible.”

The postponement of the talks underscores how brittle and delicate relations between Washington and Beijing have become, as the countries grapple with tensions over Taiwan, human rights issues in Xinjiang and Hong Kong and, most broadly, a growing military and economic rivalry.

2. The U.S. economy added a surprising 517,000 jobs in January.

After several months of cooling, the labor market produced a surge of robust job growth, despite rising interest rates. The unemployment rate fell to 3.4 percent, the lowest since 1969.

The bumper crop of hirings was widespread across industries, but a few stood out: the leisure and hospitality sector led the way with 128,000 new jobs, followed by the education and health sector. The new data underscored the challenges facing the Federal Reserve, which is trying to cool the labor market to tame rising prices without causing a major recession by hiking interest rates too high.

3. The Biden administration authorized a $2 billion package for Ukraine that includes longer-range weapons.

The aid will include money for Kyiv to purchase a new rocket-boosted weapon, the Ground-Launched Small Diameter Bomb. The new weapon can strike targets up to 93 miles away, farther away than Ukraine can currently reach with other American-made rockets.

The Pentagon said the new weapon would help Ukraine’s military “take back their sovereign territory in Russian-occupied areas.” But the new long-range weaponry comes with a hitch: It will take months to deploy, too late to be used against a broad assault by Moscow that seemingly has already begun in eastern Ukraine.

4. Are you in the Northeast? Better bundle up.

Temperature records are expected to be shattered in the coming days as the region prepares for some of the coldest wind chills in decades. Forecasters in Maine expect the wind chill in Portland to be minus 40 degrees Fahrenheit tonight. Winds gusting at 30 to 40 miles per hour combined with air temperatures well below freezing will make conditions extremely dangerous.

The core of the dangerously cold Arctic air and winds will arrive in the region tonight. Officials in New York and Connecticut, where the wind chill is expected to drop below zero, announced plans to expand access to emergency indoor shelters for vulnerable populations.

5. For Democrats, it’s Biden or bust.

Nine months ago, as gas prices soared, Democrats were concerned that Joe Biden was too frail, too politically weak and too much of a throwback to be a strong presidential candidate in 2024.

But Democrats exceeded expectations in the midterms, and they are now facing the possibility of a rematch against a far more vulnerable Donald Trump. No serious Democratic challengers have emerged, and the official party structure has united behind the president’s re-election bid.

In the Republican camp, the polls show Trump getting between 25 percent and 55 percent of the vote in a multicandidate primary field, my colleague Nate Cohn writes in The Tilt newsletter. But higher-quality surveys tend to show far less support for Trump.

6. “My watch thinks I’m dead.”

Some Apple Watches and iPhones are equipped with new technology that is meant to detect falls and car crashes and then automatically alert 911 dispatchers. But the latest update appears to send the device into overdrive: It keeps mistaking skiers, and some other fitness enthusiasts, for car-wreck victims.

Emergency call centers in some ski regions have been inundated with inadvertent, automated calls, dozens or more a week, which can divert resources from real emergencies. Apple said it had made recent updates to the software to “optimize” the technology.

7. Ordinary ice, when shaken very hard, turns into something never seen before.

Scientists studying ice crystals put super-chilled ice in a container with steel balls. A machine then shook the container and pulverized the ice into tiny bits. (Think of it as a high-tech cocktail shaker.)

What came out was a newly discovered form of ice made of a jumble of molecules with unique properties: It was denser, and much of the crystalline structure had been destroyed, producing an amorphous material.

The findings could be of use to scientists studying other planets — and show that water is still hiding scientific surprises.

8. Your brain needs a break.

Brain slumps are real. But experts say the antidote to moments like the midafternoon mind sludge isn’t muddling through, no matter what hustle culture wants you to believe. It’s the opposite: You should take a break.

Research has found that simply taking a few minutes to do a puzzle — or stare into space — can allow you to return to work sharper and more creative.

More on mental health: These common traits shared by optimists can help improve anyone’s outlook.

9. New music for your weekend.

Every Friday, pop critics for The New York Times weigh in on notable new songs. This week, they were drawn to the “sheer, euphoric infatuation” of “Blood and Butter,” the latest single from the singer Caroline Polachek.

And “Echolalia,” the breathy, percussive new single from Yves Tumor, finds the 21st-century glam rocker dazed with infatuation and cosplaying conventionality: “Just put me in a house with a dog and a shiny car,” Tumor sings breathlessly. “We can play the part.”

In other music news, the global music giant BMG secretly signed a French rapper who has been widely condemned for antisemitic lyrics.

10. And finally, honoring a junior entomologist.

Bobbi Wilson, 9, spent hours last summer using soap and water to obliterate the invasive spotted lanternflies that were ravaging her northern New Jersey community.

But then a neighbor called the police, complaining about a “little Black woman, walking and spraying stuff on the sidewalks and trees.” Officers questioned Wilson and her mother, and though no further action was taken, the incident led to a larger discussion on racial profiling — and caught the attention of Yale University.

The school held a ceremony in late January recognizing Bobbi’s anti-lanternfly efforts, and the insects she collected will be added to the school’s Peabody Museum. In an interview, Bobbi said she hoped her story would help other young aspiring scientists to “not be afraid to try something just because they’re little.”

Have an intrepid night.

Brent Lewis compiled photos for this briefing.

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