On August 21, 2017, the universe will treat the US to a most unique event – a total eclipse of the sun. The “Great American Total Eclipse” will darken the skies from Oregon to North Carolina, spanning a distance of approximately 70 miles (113 kilometers).

A partial eclipse will be observable in other parts of the country. The last time a total solar eclipse could be seen from coast to coast in the US was in 1918.

During a total eclipse, the moon passes between the sun and earth, blocking the sun temporarily and revealing its outer atmosphere—the solar corona. Such a wonder can only be visible in locations along the path of totality, while the sun’s corona is even invisible in an area with a 99% solar eclipse. During a total solar eclipse, the temperature will drop, while the horizon will light up, comparable to twilight.

Another spectacular phenomenon during the total solar eclipse is Bailey’s Beads. As the moon “grazes” by the Sun during a solar eclipse, sunlight will be blocked by mountains and valleys on the moon’s surface but shine through the lunar plains, creating the diamond ring effect or a necklace-like effect. This is also the only chance to observe the mountains and valleys on the moon’s surface with naked eyes, which is like casting off the moon’s veil of secrecy.

According to NASA’s eclipse map, the total solar eclipse will sweep over Casper, Wyoming in the western United States. Casper is directly in the path of the eclipse’s “umbra” or moon shadow. As suggested by weather information of the past 22 years, the best spots to forecast the weather will be in Northern Oregon, Idaho, Central Wyoming, and Western Nebraska. Therefore, for a glimpse of this 2017 eclipse, Wyoming will be of choice.

According to reports, hotels in or around the path of the total solar eclipse are completely booked, and many have been for a year or two. When the anticipated day arrives, over one million tourists will converge on viewing locations of the eclipse’s umbra for a memorable experience.

the author name: Yoyo Chiang