This month has seen a dramatic spike in mysterious flying objects being shot down in US airspace - four, in fact, over the course of eight days.
There’s since been wild speculation about their origin and purpose, and the downing of an alleged Chinese spy balloon has significantly worsened already fraught relations between Beijing and Washington.
Amid all the theories and finger-pointing, one thing seems certain: There are quite a lot of unidentified flying objects (UFOs) being spotted in the skies these days, and experts are taking them seriously.
Over the past two years, the US government added another 350 “UFO sightings” to its records, according to a report from the US Office of the Director of National Intelligence.
Most of these reports have come from US navy and air force pilots and operators who spotted the objects while out on duty.
But the US administration has said little about the recent shootdowns, which began with a suspected Chinese spy balloon earlier this month. Three more unidentified devices have since been downed, with the latest on Sunday over Lake Huron.
What are the flying objects spotted over North America?
Short answer - we aren’t 100 per cent sure.
Some will immediately assume the airborne phenomena translates to alien activity, but the White House said this week there is no indication of this.
The more down-to-earth are attributing the sightings to spying devices, drones or even discarded plastic bags caught in the wind.
One thing the US government isn’t ruling out is the potential security risks.
The US claims the first object it took down this month was a Chinese spy balloon. However, it has since said that the other three that were sighted within days of this first one were "probably benign".
On Sunday night, the US department of defence had said the country was now on “heightened alert,” putting more measures in place to scrutinise the skies and detect smaller objects.
China hit back on Wednesday, saying that US high-altitude balloons flew over its Xinjiang and Tibet regions and that it would be taking counter-measures, without giving details.
The downed balloon wasn’t the first to be attributed to Chinese intelligence. According to US officials cited in the New York Times, China has previously stolen plans for advanced fighter planes and now wants to learn more about how the US trains its military pilots.
A new arms race?
Jean-Vincent Brisset, an expert at the Institute of International and Strategic Relations (IRIS), has another theory - one that involves a new arms race high in the upper atmosphere.
"Currently, the United States, but also China, France, no doubt Russia, and other major countries, are doing research to try to develop new weapons, so-called hypersonic gliders," he told Euronews.
"A large part of the flight of these devices takes place in the stratosphere. We know very little about the stratosphere, in terms of composition, in terms of the winds that circulate," he said.
The alleged spy balloon was flying 18 km above Earth, in the stratosphere - higher than where planes fly, but below where outer space begins.
Could the UFOs be of alien origin?
When asked during a briefing on Sunday if the airborne objects could be extra-terrestrials, US Air Force General Glen VanHerck replied: "I haven't ruled out anything".
But before we get carried away with thoughts about what’s out there, it’s worth noting that Ronald Moultrie, the country’s undersecretary of defence for intelligence and security, has also stated “we have not seen anything that would lead us to believe that any of the objects that we have seen are of alien origin, if you will”.
White House press secretary Karine Jean-Pierre also sought to quash that theory on Monday.
“I know there have been questions and concerns about this, but there is no - again no indication - of aliens or extraterrestrial activity with these recent takedowns,” she told reporters. “I wanted to make sure that the American people knew that”.
It seems government officials believe the most recent cases can rather be attributed to surveillance operations by other countries, weather balloons or unidentified airborne clutter. All quite ordinary.
Of 366 unexplained aerial phenomena (UAPs) reported in the US since March 2021, more than half were listed as having “unremarkable characteristics,” including 163 characterised as “balloon or balloon-like entities”.
The other “unremarkable” sightings were characterised as drones or drone-like objects, or attributed to weather events, birds or airborne debris like plastic bags.
However, 171 of the reports remained uncharacterised and “have demonstrated unusual flight characteristics or performance capabilities and require further analysis,” according to the report.
Is spying getting worse?
If you ask Twitter, of course it is. Pointing the finger of blame spans from Trump being too lax with other countries’ access to US airspace, to Biden not being a strong enough leader to stop it happening. There’s also a lot of vitriol directed towards China.
Since the US accused China of using a balloon to spy, relations between the two countries have dramatically deteriorated, with US Secretary of State Antony Blinken cancelling a planned trip to China.
The US government has even gone so far as to warn other global powers about a worldwide surveillance project they believe China has a hand in, with UK Defence Secretary Ben Wallace telling The Telegraph that “the UK and her allies will review what these airspace intrusions mean for our security".
“This development is another sign of how the global threat picture is changing for the worse," he said.
While China has admitted responsibility for the balloon, it claimed it was a weather-measuring device that had travelled off course. However, it has given no details on what company or government department was responsible for the giant balloon, the remnants of which are being sent to an FBI lab for analysis.
Instead, Beijing hit back saying that high-altitude balloons belonging to the US had flown over its own airspace without permission more than 10 times since early last year.
Should we be worried?
The US believes the balloons are part of a “high-altitude programme” designed to gather intelligence and linked to the Chinese army, said John Kirby, the US National Security Council’s coordinator for strategic communications.
He added that the US cannot "definitively" identify what the risks of the balloons are.
The threat posed by these unidentified flying objects is being closely monitored well beyond North America.
UK Prime Minister Rishi Sunak has gone so far as to say his government will do “whatever it takes” to protect the country, announcing a security review on Monday.