World Mourns Loss of Skier. U.S. Freeskiing, and the entire U.S. Ski and Snowboard Association family, joined the Park City community in mourning the passing of Sam Jackenthal, a wonderful young man and a remarkable athlete.
The least dense layer of the earth is the Crust , the mantle is second densest , whereas the core is the most dense layer of the earth
Earth's atmosphere has no definite boundary, slowly becoming thinner and fading into outer space. Three-quarters of the atmosphere's mass is contained within the first 11 km of the surface. This lowest layer is called the troposphere. Energy from the Sun heats this layer, and the surface below, causing expansion of the air.