You’ve probably heard by now to watch out for a total solar eclipse in the United States on Aug. 21. But do you know exactly what it is and what will happen when it occurs?
Here’s what you need to know:
What is a total solar eclipse?
To truly understand a total solar eclipse, you must be familiar with the different types of eclipses.
An eclipse is when one astronomical body, such as a moon or planet, moves into the shadow of another astronomical body. There are two types of eclipses on Earth: a lunar eclipse and a solar eclipse.
A lunar eclipse occurs when Earth moves between the sun and the moon, with its shadow blocking the sunlight that causes the moon to shine. This can only occur when the moon is full, according to NASA.
A solar eclipse occurs when the moon moves between the sun and Earth, blocking the sunlight and casting a shadow onto Earth. There are four main types of solar eclipses: partial, annular, total and hybrid, according to NASA.
A total solar eclipse is when the moon moves between the sun and Earth, lasting for up to about three hours from beginning to end.
Total solar eclipses occur once every 12 to 18 months while partial solar eclipses, when the moon blocks only part of the sun, occur more frequently, though visibility varies, according to NASA.
You must be in the path of totality to witness a total solar eclipse. The path of totality for the Aug. 21 eclipse is a 70-mile-wide ribbon that will arc across the continental United States from west to east. This stretches from Lincoln Beach, Oregon, at 9:05 a.m. PDT to Charleston, South Carolina, at 2:48 p.m. EDT.
From there, the moon’s shadow leaves the country at 4:09 EDT.
What happens during a total solar eclipse?
During a total solar eclipse, the lunar shadow will darken the sky and temperatures will drop while bright stars and planets will appear at a time that is normally broad daylight.
Retired NASA astrophysicist and photographer Fred Espenak said the experience usually lasts for just a couple minutes, but it’s truly out of this world.
Some animals may react strangely to the celestial phenomenon. Rick Schwartz, an animal behavior expert with the San Diego Zoo, said there have been observations of animals going to sleep during total solar eclipses.
“The animals take the visual cues of the light dimming, and the temperature cues,”
“You hear the increase of bird calls and insects that you usually associate with nightfall,” he added. “Farmers have said that the cows lay down on the field or the chickens go back into the coop.”
Who Can See It?
Lots of people! Everyone in the contiguous United States, in fact, everyone in North America plus parts of South America, Africa, and Europe will see at least a partial solar eclipse, while the thin path of totality will pass through portions of 14 states.
This map shows the globe view of the path of totality for the August 21, 2017 total solar eclipse.
To check a more detailed interactive map click here
How Can You See It?
You never want to look directly at the sun without appropriate protection except during totality. That could severely hurt your eyes. However, there are many ways to safely view an eclipse of the sun including direct viewing – which requires some type of filtering device and indirect viewing where you project an image of the sun onto a screen. Both methods should produce clear images of the partial phase of an eclipse.