The Great American Solar Eclipse is almost upon us, and it’s the first eclipse to in the continental United States in nearly 40 years. On Aug. 21, the moon will blot out the sun for a several minutes in a narrow band of the U.S. stretching from Oregon to South Carolina. But there are some things about the solar eclipse you might not realize.

If you stand fully in the moon’s shadow this August, you will feel something astonishing that is unlike anything you can experience anywhere else. When the eclipse happens, the temperatures will plunge nearly 30 degrees for a few minutes. Some have described it as being like space itself touching you.

Basically, it’s like instantly going from the heat of the day to after sunset. So it’s more than just seeing the Earth go dark in the middle of the day, it’s about experiencing something that is positively otherworldly.

“When the moon blocks out the sun during a total eclipse, those regions of Earth that are in the direct path of totality become dark as night for almost three minutes,” said Steve Clarke, director of the Heliophysics Division at NASA Headquarters in Washington, D.C., in a NASA statement. “This will be one of the best-observed eclipses to date, and we plan to take advantage of this unique opportunity to learn as much as we can about the sun and its effects on Earth.”

The statement adds: “The August 2017 total solar eclipse will provide a unique opportunity to study Earth, the sun, and their interaction because of the eclipse’s long path over land. The path of the total eclipse crosses the U.S. from coast to coast, so scientists will be able to take ground-based observations over a period of more than an hour to complement the wealth of data provided by NASA satellites.”