Great American Eclipse: What really happens in path of totality?

Meteorologist breaks it down, stage by stage

Getty Image
Getty Image

(GMG) – Why do solar eclipses happen? What will the country experience on Monday? We touched on those topics last week, so now it's time to get much more detailed and granular: Let's chat about what will happen for those lucky enough to be in the path of totality.

First things first. For most of the period before and after totality, you won’t notice a thing unless you look at the sun with approved solar eye protection. 

Never look at the sun without eye protection, as permanent eye damage or blindness will occur.

Those watching with eclipse glasses, for example, will see an increasing chunk taken out of the solar disk as the moon starts passing in front of it. After the moon covers 80 to 90 percent of the sun, the ambient light may look a little dimmer, and you may notice subtle color changes around you. 

As you get close to the start of totality, that last patch of bright sunlight makes the nearly eclipsed sun look like a diamond ring. And to give you an idea of how smart scientists are, they call this the diamond ring effect.

Diamond ring effect (from NASA):


As the “diamond” disappears, the next thing you’ll see (for just a few seconds) is a series of little dots, or “beads,” on the rim of the sun where the “diamond” just was.  This is the result of the last remaining little bits of sun shining between mountains and through deep valleys on the edge of the moon, and it's called Baily’s Beads.

Baily’s Beads (from NASA):


After Baily’s Beads disappear, you enter the most exciting part of an eclipse: Totality. The sun is now completely covered by the moon, and the only part of the sun visible is its corona, or atmosphere -- which can only be seen during a total solar eclipse (the corona is pretty amazing: While the sun’s surface temperature is about 10,000 degrees Fahrenheit, temperatures in the corona rise to between 3 and 4 MILLION degrees).

You can now take off your eye protection and look at the eclipsed sun because, at this point, daylight has faded into night. The brightest stars and planets are visible in the sky. Animals and insects get confused and begin nighttime behavior. The temperature starts dropping. This phase of the eclipse only lasts a couple of minutes in the prime areas, and ends with the sun’s western edge starting to brighten, quickly followed by Baily’s Beads and the diamond ring effect once again, and then a rapid brightening of your overall surroundings.

Experiencing a total solar eclipse is an extraordinary event. Not only is what we described above so incredibly amazing, but what makes it even more special is how rare it is. While eclipses happen around the world every year or two, many of them occur in relatively inaccessible areas. The Great American Eclipse of 2017 is getting so much hype because it will travel across our entire country, with tens of millions of people in the path of totality (not to mention everybody else who will travel to the area). 

The last total eclipse in the U.S. was in 1979.  Fortunately, the next one is in 2024, and that one will travel roughly from Texas to Cleveland.

Firm up your last-minute plans, if you haven't already.

Written and compiled by meteorologist Paul Gross

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