Gravity constantly affects the landscape of the earth. It pulls down on the mountains, breaking off pieces, and causing the formation of smaller rocks that come rolling and crashing down. As the rocks fall, they break into other pieces, and gravity pulls them farther down, creating sand and other fine particles. Winds pick up the sand and blast them against the features of the landscape, causing erosion.
Glaciers, which are essentially frozen rivers of ice, grind the earth beneath them as they slowly move downhill under the influence of gravity, changing the land surface in a process called glaciation. Glaciers change the surface in three main ways: abrasion, plucking and ice melts. When pieces of rock scrape against other surfaces, they abrades them, leaving behind deep grooves or sanded areas. Ice chunks sometimes tear loose, taking layers of bedrock with them in a process known as plucking. When ice melts and re-freezes, it cracks the bedrock and causes breakages in the bedrock.
Water vapors that turn into rain fall to the ground thanks to gravity. Rain, particularly heavy rain, can cause landslides or other erosive events. Gravity also is the force that creates streams, rivers and waterfalls, as the water is pulled down towards the surface of the earth. As it "falls," the water cuts channels, undermines banks, overflows its bank and changes in the landscape in many other ways. The Grand Canyon is a prime example of the erosive power of gravity-fueled water, carved over millions of years by the Colorado River being pulled down all the way from the Colorado Rockies to the Gulf of California.
Gravity winds cause erosion in areas with mountains and glaciers. Cold, dense air is pulled downward from the tops of mountain slopes or glaciated slopes. Fast and slow winds push and pull on rocks, ice, snow or dirt on the slopes, pulling them down. Slow-speed gravity winds are known as drainage winds, and strong, high speed winds are known as katabatic winds.