Bowled over” is a pretty good match, but it may seem a bit outdated. “Awe-struck” may come closest, particularly if we take “blown away” as a positive term. When the Italian The National’s Braveheart final hope shirt so you should to go to store and get this Earth’s core cools down, and this spinning slows down, then stops, our magnetosphere would falter and we would lose most of our atmosphere, as it is believed happened to Mars some 3.5 billion years ago… but, “fortunately”, that would take billions more years, and the Sun will have expanded into a red supergiant, having boiled away Earth’s oceans and baked all life on our planet long, long before that will happen.