Produced by Evans & Sutherland
Duration 25 min.
Grades 5 & up
Ice Worlds explores the role of ice in the universe. It is found in the rings of Saturn, the mountain-sized dirty snowballs we call comets, as the moons of the outer Solar System, and covering the polar regions of the Earth.
A telescopic view of Earth from Mars would reveal the blue of the oceans, the brownish green of the continents, and the white of the polar caps. It would show that the polar regions grow and shrink with the seasons and that the northern polar region has decreased in size. As a result, submarines are now able to surface at the North Pole during the summer months.
The Earth’s South Pole, a continent the size of the United States with rivers and lakes, is buried below a thick sheet of ice. Rising through the ice are mountains and volcanoes. Where winds sweep across areas devoid of snow, dry valleys reveal pristine lands.
The surface of Mars resembles the dry Antarctic valleys. Mars, like Earth, has polar caps layered with ice and frozen carbon dioxide. These layers may show changes in the Martian environment and were investigated by the Phoenix Lander searching to see if conditions could support life on an icy world.
Comets crossing the orbit of Mars, on their way through the inner Solar System, begin an active phase in which ices sublimate (go from a solid directly to gas) forming their long tails.
Europa, a moon of Jupiter, has an icy crust that shows signs of melting and freezing with rafts of ice moving across the surface. The evidence suggests that there is an ocean below the icy crust. Saturn’s moon, Enceladus, spews water vapor from fissures on its surface. Saturn’s moon, Titan, a world as big as Mercury, is composed of ice frozen as hard as rock. The moon Triton, which orbits Neptune, has geysers shooting plumes of material five miles above the surface. The ice worlds outnumber the other planets of our Solar System.
Earth has experienced ice ages in the past. We live in a warm period, between ice ages, which may be enhanced by human activity. Evidence of the changes comes from cores of ice drilled out of ice sheets in Greenland and Antarctica and similar cores of sediment on the bottom of Earth’s oceans. The ice cores are a time capsule that provide a 400,000 year history of Earth’s changing environment.
During our current warm period, ice is melting in Greenland, and the northern polar cap is thinning with less ice cover each year. There may be no Arctic ice cap during summer months in as little as fifty years. Melting ice can affect climate by changing the temperature of ocean currents.
There are also periodic changes in Earth’s orbit that result in ice ages. Just 20,000 years ago the location of New York City was covered with a thick sheet of ice. With water trapped in ice, the sea levels dropped. The area that we know today as Great Britain was two-thirds covered in ice. The resulting drop in sea level caused the area to be connected to Europe instead of surrounded by water like it is today.
Antarctica holds 2/3 of Earth’s fresh water in its ice sheet. Surrounding Antarctica is a rich marine ecosystem with algae and krill (a tiny shrimp-like crustacean) at the base, and seals, penguins, and whales higher in the food chain. Our current warming period is melting the ice. This is lowering the salt level in water and causing a decrease in the krill, which may ultimately affect seal, penguin, and whale populations.
Studies of the Ice Worlds on Earth and throughout the university, lead to a better understanding of our own world.