Does the Earth blow raspberries at the sky when it thinks no one is watching? Sadly, no. What looks like a giant bubble rising and expanding in space in this video taken on 22 June from Hawaii is actually just exhaust from a missile launch.

Astronomer Phil Plait brought the video – and the missile explanation – to public notice yesterday in his blog, Bad Astronomy.

The video had been discussed on another astronomy forum and there commenters had already suggested the timing was right for the source to be a Minuteman III missile, which had launched from California's Vandenberg Air Force Base a few minutes earlier.

I'm not convinced, yet. To read the rest of the article, click here.