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Comment by josefresco | Hacker News Reader

Confusing because in their FAQ they state the following:

"We are flying in the stratosphere well above commercial air traffic and weather events, at around 18 - 27 km or 60,000 - 90,000 feet. "

I wonder if the "around the world" flight was done under different conditions?

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Wind speeds in the upper atmosphere can be very fast. These balloons will not be stationary. Based on my limited knowledge of the project, the only way they could have consistent coverage would be to have evenly spaced balloons around the Earth. That assumes that wind currents would cause the balloons to travel around the Earth in a dependable pattern. Considering the circumference of the Earth 40,008km and 80km coverage diameter, 40008 / 80 = 500 balloons would be required at minimum if all the balloons traveled at the same speed and in a dependable pattern. I would imagine the wind currents the balloons would travel on would be greater than the Earth's circumference, so more than 500 balloons would be required. Also, I doubt the balloons could maintain a perfect 80km spacing. I can think of other factors that would make dependable coverage difficult.

Here's a wikipedia article explaining it.

http://en.wikipedia.org/wiki/Geostationary_balloon_satellite

These balloons will not be geostationary.

At least read the link that was posted? Because otherwise, you miss parts like this from the linked article:

"This is the ideal height because Air density is 1/10th of what it is at Sea level. This makes the wind at these altitudes 10 times less potent."

No, independent of whether it's possible to make a geostationary balloon, Google's balloons are not going to be stationary. They are steered purely by changing altitude and riding high-altitude winds.

Sure, except, the context of this sub-thread was started by someone claiming that winds in the upper atmosphere "can be very fast." So the link was to correct/explain to them, not to claim that the Google Balloons would be stationary.

Stratospheric wind speeds are very fast. Look it up if you don't believe me. I was just basing this from a quote in the original article "wind speeds as high as 291 km/h".

@coderzach, I've read other articles on Google Loon and a number of the articles mention the balloons moving around the Earth. I have not ready anything about the balloons being geostationary. If you have, please share.

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