![]() ![]() The light scattering in the atmosphere above your location will change, as will reflected and scattered surface light from further than your visible horizon. ![]() That is simply a phenomenon that does not happen in any other situation, ever. So, if you’re in the middle of an eclipse umbra spanning 100 to 150 kilometers, absolutely everything within your horizon, and quite a bit more, will be simultaneously shaded from the Sun. Climb up a hill of about 100 feet and you can see a bit further – to perhaps 20 kilometers. If you stand outside on a non-mountainous part of the planet, the visible horizon is only about 5 kilometers around the Earth’s curved surface from your location. By comparison, on August 21 st 2017 the North American eclipse will have an umbra spanning roughly 115 kilometers, and at best a 2 minute totality for the luckily positioned.Īll of which gets me back to the shock-and-awe piece of a total eclipse. For example, in December of 2067 a solar eclipse will take place with a small umbra, giving a viewer a mere 8 seconds to enjoy totality. The larger the umbra, the longer the total eclipse for an observer.īut if the Moon is at its furthest the umbra can disappear, leaving just an antumbra, or a very brief umbra. If the shadow intersects the planet at higher latitudes the umbra can stretch out to perhaps 1,000 kilometers due to the shallower angle of the light rays from the Sun. For an eclipse crossing the Earth’s equator, with the Moon at its closest to us, the scale of the umbra is roughly 150 kilometers across. The inner umbra of total eclipse, the outer penumbra of partial eclipse, and the antumbra between these two if the moon’s distance allows an annular eclipse – the Sun peeking around the lunar disk. This shadow is really divided into three zones, depending on the eclipse configuration. After all, a stray cloud can do a pretty good job at blotting the Sun out, as can a well-placed umbrella or hand.Īnd that got me interested in the actual dimensions of the shadow cast by the Moon. It’s in the alien vista of the Sun’s corona, or in the spectacle of Bailey’s beads, or the sudden chill that descends on an otherwise warm sunny day and the wind that whips up.īut what’s bothered me is why some of these phenomena should have such a visceral impact. That awe come from different pieces of the experience. What’s common to almost all of these descriptions is the genuine sense of awe that a blocked-out sun evokes. In recent days I’ve been reading a few eye-witness accounts of total solar eclipses across the ages. ![]()
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