On Aug. 21, you'll likely be looking to the sky in the middle of the day.

A solar eclipse 99 years in the making will move across the country.

It'll start in Oregon, and move across the United States to South Carolina.

Starting at 9 a.m. Pacific time and ending at 4 p.m. Eastern time, the eclipse will be seen across the country.

The unique thing about this eclipse is that for some parts of the country, the sun will be completely blocked out, but for those living outside of the direct path -- we'll also get to see part of the sun being blocked by the moon.

The eclipse will provide a wealth of information to scientists, including information about the sun, the atmosphere, and even animal and plant behavior.

Angela Speck, a professor and astronomer, spoke on a panel as part of a NASA briefing on Wednesday afternoon. During the eclipse, she'll be studying animal and plant behavior.

She says animals react differently during different parts of the day.

For example, at twilight, birds tend to swarm around and make a lot of noise. Other animals, like cattle, may go back to the barn when the eclipse happens. Speck will be gathering data as animals and plants react to the eclipse this August.

The next time we'll see this sort of thing happen again will be in April of 2024.