More than 75% of the earth's surface consists of sedimentary layers that were formed in water. The areas of sedimentary layers are incredibly vast. In each layer, the sediment is consistent in its components, and the boundaries are almost parallel to each other. It proves that the earth was once completely covered with water, which caused sedimentary layers to appear in a short period of time due to high and low tidal currents caused by gravitational forces between the sun, the moon, and the earth. Scientists finally concluded a world-wide flood such as Noah's flood would be necessary to form such vast sedimentary layers on the earth's surface. This evidences the authenticity of the Bible.