Shutter Speed aka (exposure time) , stands for the length of time a camera shutter is open to expose light into the camera sensor - is one of the three pillars of photography, the other two being ISO and Aperture
moment earthshaking-the shutter speed is slowed making the swings appear in motion and gives off an earthshaking sort of appeal carnival festival fair swing photo
In this image, the blur of people moving around in the crowd makes it look interesting, but it is also focusing on particular people who are standing, walking, moving in what looks like a busy area. A slow shutter speed is used in this image.