Time-Lapse Video: The Rising Slow-Motion Dance of the Eclipsed Sun and Moon

05-15-2013 • http://www.slate.com, By Phil Plait

That photo was part of a time-lapse video that, at the time, was being put together by photographers Colin Legg and Geoff Sims.

They finished it. Trust me: Take two minutes of your life, make this full screen, sit back, and be in awe of the show nature puts on for us.

This eclipse was from last week, May 10, when the Moon passed directly in front of the Sun. The Moon’s orbit is elliptical, and it happened to be at a point where it is farther away than average when the eclipse occurred. Usually, the Moon and Sun are about the same size in the sky, but in this case the Moon’s added distance made it a bit smaller, and it couldn’t completely cover the Sun’s face. It left a ring, or annulus, of Sun circling the Moon’s silhouetted disk.

There were three major effects playing together to make this cosmic ballet so amazing. One is simply the daily turning of the Earth, so that we see the Moon and Sun rising. The second is atmospheric effects distorting the shape of the two as they rose. Near the horizon, this effect is very pronounced; it acts to flatten objects, so as they rise they look like they stretch out into their normal shape.