Although science can't say for sure, ice ages are thought to be triggered by the interaction between the height of the continents, the circulation of the ocean, the distance of Earth from the sun, the atmosphere's composition and solar output. Scientists say that, as of 2014, the Earth is in the midst of a major cooling period. This cooling period began about 3 million years ago.Continue Reading
The Earth has gone through warm and cold periods during the billions of years of its existence. During ice ages, the polar regions of the Earth are cold, and there are large glaciers covering vast regions of the planet. Ice ages tend to occur for millions or even tens of millions of years, and generally happen every 200 million years or so.
Scientists say that the present ice age that is being experienced by the planet has caused the retreating and advancement of glaciers more than 20 times. The existing climate is due to a warm interval between the periods of glacial advancement. What most people refer to as "The Ice Age" was actually a period of glacial advancement that occurred about 20,000 years in the past as part of a larger cycle.Learn more about Prehistory
Several causes can be attributed to deserts, including the Earth's air circulation pattern, the rain shadow effect, the distance from the ocean and the proximity of cold ocean currents. Some common deserts in the United States include the Colorado Plateau that stretches through Colorado, Utah, Arizona and New Mexico, and the Basin and Range in Nevada, Utah, California and Arizona.Full Answer >
The Paleozoic Era saw changes to Earth's landscapes, life forms and atmosphere over the course of several million years. On land, at sea, below the surface and in the skies, change occurred throughout the six distinct periods comprising the Paleozoic Era. The early Paleozoic periods introduced many plant species, while later periods brought invertebrates, dinosaurs and birds.Full Answer >
Containing everything from the ocean basins to continents, the crust is the outermost layer of the Earth. Overall, the crust makes up very little of the Earth's mass, so the other layers, which are the mantle, outer core and inner core, are much thicker.Full Answer >
Saturn is the sixth planet from the sun at a distance of 886 million miles and has a composition of hydrogen and helium. Saturn was first observed through a telescope by Italian astronomer Galileo Galilei.Full Answer >