A Timeline of the U.F.O.s That Were Shot Down This Weekend

The U.S. military shot down at least three unidentified flying objects over the weekend after a Chinese spy balloon that had invaded American airspace was downed on Feb. 4, setting off a diplomatic crisis.

There are certainly more questions than answers at this stage, including what the objects were, their purpose and who sent them.

What is known is that the U.S. and Canadian militaries have become hypervigilant since the Chinese spy balloon incursion. The North American Aerospace Defense Command, or NORAD, has adjusted its radar system to become more sensitive, sharply raising the number of objects it detects.

Here’s a quick timeline of events.

Feb. 4: A Chinese spy balloon is shot down over the Atlantic Ocean.

The balloon entered Alaskan airspace on Jan. 28, Pentagon officials said, and later drifted from Idaho southeast to the Carolinas before it was shot down on the afternoon of Feb. 4, about six miles off the coast of South Carolina.

A F-22 fighter jet fired a Sidewinder air-to-air missile at the balloon, which was equipped with solar panels to power propulsion, cameras and surveillance technology. The balloon, which was about the size of three buses, was flying at an altitude of 60,000 to 65,000 feet.

In the aftermath, Secretary of State Antony J. Blinken canceled a trip to China; it would have been the first by a Biden cabinet secretary.

Feb. 10: A U.F.O. is shot down off Alaska.

On Friday, a U.S. fighter jet brought down an unidentified object over the icy waters of Alaska. The object broke into pieces after being shot down and was most likely not a balloon, a Defense Department official said. A White House official said the object was the size of a small car.

The object was first detected on Thursday night, Alaskan time, and had traversed over land in Alaska and was headed toward the North Pole before it was struck down.

Feb. 11: A U.F.O. is shot down over Canada.

An American F-22 fighter with NORAD downed another object on Saturday over the Yukon Territory, which borders Alaska. The object, which a Canadian official described as cylindrical and smaller than the spy balloon, was picked up on radar late Friday as it passed over Alaska.

It was unclear what the object was, but Prime Minister Justin Trudeau of Canada said on Twitter that the object had violated Canadian airspace. Canadian Forces would recover the analyze the wreckage, he said.

Feb. 12: A U.F.O. is shot down over Lake Huron.

An object first appeared over Montana on Saturday and then disappeared, leading officials to conclude that it was an anomaly. But the object reappeared on Sunday over Montana, then over Wisconsin and Michigan. The object, which was flying at 20,000 feet and posed a potential threat to civil aviation, had an octagonal structure with strings hanging off but had no discernible payload, U.S. officials said.

An F-16 shot down the object over Lake Huron.

National security officials on Sunday discounted the possibility that the objects shot down over the weekend might have extraterrestrial origins. However, Gen. Glen D. VanHerck, the commander of the Air Force’s Northern Command, said during a news conference, “I haven’t ruled out anything at this point.”