They are brief, but they can be longer than 2 seconds. They can easily last 7 seconds. Some even longer. Also, they can migrate across a huge swath of the sky a

They are brief, but they can be longer than 2 seconds. They can easily last 7 seconds. Some even longer. Also, they can migrate across a huge swath of the sky and when you confuse a person's visual system, they have to interpret it. Obviously, I don't know for sure. But I checked and there was one in the area with a pretty long duration depending on where you are.