evidence: Pentagon officials announced on Thursday that they had detected a Chinese "surveillance balloon" flying over Montana. On Friday the Pentagon’s press secretary said that the balloon is now over the central U.S. and moving eastward at an altitude of about 60,000 feet. Observers on the ground have been able to snap photographs and videos of the object, and the incident has prompted Secretary of State Antony Blinken to cancel a planned trip to China. Although China’s Ministry of Foreign Affairs quickly claimed that the object is merely a civilian weather observatory blown off course, later on Friday, the Pentagon press secretary, Air Force Brigadier General Patrick Ryder, held a press briefing where he stated, "We know that it’s a surveillance balloon.... We know this is a Chinese balloon and that it has the ability to maneuver." [...] How can the Pentagon tell it is actually a spy balloon, as opposed to a civilian project for meteorology research, as the Chinese Ministry of Foreign Affairs claimed?