More Earth Science Facts
Air From Volcanoes
When the Earth was first formed the only air on the planet was hydrogen. Since hydrogen is very light it eventually floated away. Earth had volcanoes on it and when they erupted they leaked out water vapor and carbon dioxide. The air did not contain any oxygen at this time so no animals could survive at this stage of Earth.
The Hurricane That Prevented War
Three American warships were going to attack three German ships and one British ship for destroying American property in Samoa. Before the war could begin a hurricane came through the harbor and sunk the German and American ships, along with six merchant ships. The British ship survived because it had an engine on it, and was able to escape.
Convection
Convection occurs when warm air rises and cool air sinks. When a layer of air is heated, it expands and moves upward. Colder, heavier air then flows underneath it. That cold air is then warmed, and it expands and rises. The warm rising air cools as it reaches higher, cooler regions of the atmosphere, and it too begins to sink. Breezes, winds, and thunderstorms may result.
The Ozone 'Shield'
The ozone layer is a thin layer of ozone gas (O3) which exists in the Earth's stratosphere and shields us from dangerous levels of ultraviolet radiation. NASA satellites, aircraft, balloon, and ground measurements have helped to identify the effects of chlorofluorocarbons (CFS's) on the ozone layer. One of these effects is the "ozone hole", an area of extreme ozone depletion, which forms during Antarctica's spring and has been getting larger over the past 20 years. Since it's discovery in 1983 by Dr. Joe Farnman, and as a result of research done by U.S. and European scientists, many nations have agreed to ban the production of CFC's.
Greenhouse Effect
Certain gases in the atmosphere, such as water vapor, carbon dioxide, and methane (among others) are particularly transparent to sunlight. As sunlight comes through the atmosphere, most of it reaches the Earth's surface. This sunlight is absorbed by the surface of the Earth and re-emitted as heat (called infrared radiation). But these same gases are not transparent to the heat that the Earth emits. they absorb some of it, and part of what they absorb is radiated back to the surface of the Earth. The overall effect being that these gases "trap" some of the heat, and thus, like a blanket, they make the Earth warmer than it would otherwise be.
Satellite Radar Imaging
Satellites use sophisticated cameras and instruments that can "look" through clouds to the sea's surface and measure, temperature, wave height, and current directions. Scientists use this information to predict, for example, how weather may be affected by an El Nino event.
Earth's Water
Oceans are central to the continued existence of life on our planet. The oceans are where life first appeared on Earth. The largest creatures on Earth (whales) and the smallest (bacteria and viruses) live in the oceans. We rely on the ocean for many things, including food, water, transportation, recreation, minerals and energy. Oceans store energy. When ocean currents change, they cause changes in global weather patterns and can cause droughts, floods, and storms.
The Jet Streams - Rivers of Air
Jet Streams are rivers of air moving at high speeds in the atmosphere. Jet streams form along the boundaries of global air masses where there are significant differences in atmospheric temperature. A jet stream may be several hundred miles across, 1-2 miles (2-3 kilometers) deep and at an altitude of 8-12 miles (9-14 km). They generally move west to east, and are strongest in the winter with wind speeds getting as high as 250 mph (400 kph). In contrast, the strongest type of hurricane has winds that blow at 156-200 mph (250-320 kph).
Warm Moist Air
The amount of water in the air depends on the air temperature. Warmer air can hold more water because the 'space' between molecules is larger. When warm, wet air meets cool, dry air, the warm air starts to cool and the water it contains falls out as rain.
Hurricanes
Although hurricanes lose power rapidly as soon as they pass over land, they can cause high waves and tides up to 25 feet (7-8 meters) above normal. Waves and heavy flooding cause the most deaths during a hurricane. The strongest hurricanes can cause tornadoes by causing rapidly moving, strong thunderstorms. Ten minutes of one hurricane contains enough energy to match the nuclear stockpiles of the world.
Updated: January 22, 2003
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