A total solar eclipse has begun. Totality will last up to 4 minutes, 28 seconds in certain spots.

The eclipse is crossing North America, darkening skies along a path through Mexico, the United States and Canada.

Here's the latest:

DALLAS STUDENTS ELATED BY ECLIPSE

DALLAS—Emergency lights clicked on outside D.A. Hulcy Middle School as the last sliver of the sun disappeared. Students cheered and whooped, sitting on towels and picnic blankets in an adjacent parking lot.

"I'm a new person," eighth grader Nia Modkins said.

Students and teachers took off their eclipse glasses and pointed at the sky, taking pictures and videos. Once three minutes elapsed, their teachers told them to put their eclipse glasses back on as the sun prepared for its return act.

The US and Japan are sponsoring a resolution for debate by the United Nations security council which—if passed—will reaffirm international commitments to the 1967 outer space treaty (OST) forbidding the deployment and use of nuclear weapons in space.

The call, headed by US ambassador Linda Thomas-Greenfield and Japan's foreign minister Yoko Kamikawa, follows troubling reports that Russia could be developing a nuclear capable anti-satellite weapon. As an expert on space and nuclear weapons, I find these reports concerning but not surprising because nuclear anti-satellite weapons have been proposed since the cold war in the 1960s.

So far, little is known about this weapon. The White House has said it is not operational and does not pose an immediate threat. Russian president Vladmir Putin, meanwhile, stated that Moscow had no intention to pursue a weapon that puts Russia in contravention of their commitment to the OST.

A chilly, midday darkness fell across North America on Monday as a total solar eclipse raced across the continent, thrilling those lucky enough to behold the spectacle through clear skies.

Eclipse mania gripped all of Mexico, the U.S. and Canada, as the moon swept in front of the sun, blotting out daylight. Almost everyone in North America was guaranteed at least a partial eclipse, weather permitting.

It was the continent's biggest eclipse audience ever, with a couple hundred million people living in or near the shadow's path, plus scores of out-of-towners flocking in.

Clouds blanketed most of Texas as the total solar eclipse began its diagonal dash across land, starting along Mexico's mostly clear Pacific coast and aiming for Texas and 14 other U.S.