THE White House press secretary has found it necessary to reassure Americans that aliens are not involved with all the recent balloon activity. It would be a remarkable event to have a balloon arrive from outer space but presumably social media has found a way round that problem.
What has not yet been mentioned is that there are 92 weather stations run by the US Weather Service plus 30-odd in Canada which are releasing balloons every 12 hours. Suspended below each is an instrument package which sends back information about temperature and wind as the balloon ascends.
The balloons are about five feet in diameter when launched but they expand as they rise and pressure drops. They may be up to 26 feet (eight metres) by the time they burst at something around 60,000 feet and often higher than that. A small parachute is supposed to bring them down gently.
This is going on all over the world. China has 120 weather stations doing exactly the same thing. Scientists have often used much bigger balloons for other investigations: cosmic ray research, for instance. These are intended to drift along in the lower levels of the stratosphere at a height of up to 100,000 feet for as long as possible.
Running right round the world are the high-altitude very strong westerly winds known as the jet stream. This was blowing on Monday February 13 at around 35,000 feet over the Pacific Ocean with a central speed of about 190 knots. It turns north after leaving China, then with a dip in the middle arrives over Alaska before turning southwards along the west coast of Canada and the US and eventually striking north up the US east coast and out over the North Atlantic.
The Japanese did it first. They discovered this band of high winds during the Second World War and sent up thousands of balloons carrying explosives during 1944-1945, hoping they would reach the US. Three hundred of them were known to have landed. The only casualties were a woman and her five children on an outing in Southern Oregon.
It does seem at least feasible that the current spate of Chinese balloons has ended up over the US because that is where the jet stream took them. There was talk about them being controlled, but that could surely only happen if the device had a motor of some sort. Would balloon surveyance offer any advantage over satellite observation?
When the US have investigated the electronic devices they recovered from the first balloon they shot down, we will know (if they tell us) whether it was a meteorological experiment or a new way of spying, the first remotely-controlled balloon in the world capable of hovering over military installations.
The right sort of balloon can drift right around the world and reach 170,000 feet, but it takes a really clever, and so far not invented, type to be remotely steered and controlled.
PM Sunak has said this country would shoot down any of these spy balloons, but it would be quite a remarkable feat for one to reach here from China.
I think our Prime Minister, like many journalists, needs to take advice from a meteorologist before making more comments. Mind you, we wouldn’t have our crazy wind farm plans if someone had thought to ask the Met Office how many windless days we can expect in winter.