Planning the urban climate of the future
What a tree needs to grow and how it affects its surroundings vary from species to species. This makes it increasingly important for cities to adapt the urban tree cover to local conditions.
What a tree needs to grow and how it affects its surroundings vary from species to species. This makes it increasingly important for cities to adapt the urban tree cover to local conditions.
Environment
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For the first time, NASA data about nitrogen dioxide (NO2), a harmful air pollutant, is available on the Environmental Protection Agency's (EPA) widely used Environmental Justice Screening and Mapping Tool (EJScreen). This ...
Environment
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A multi-institutional team of Earth scientists, environmental engineers and geomaticists has found via satellite study that modern cities around the world have been growing upward more than outward. In their research, published ...
China says it launched a rocket Tuesday carrying a constellation of a reported 18 satellites as part of efforts to assert its presence in space.
Space Exploration
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In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavor. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon.
The first artificial satellite, Sputnik 1, was launched by the Soviet Union in 1957. By 2009 thousands of satellites have been launched into orbit around the Earth. These originate from more than 50 countries and have used the satellite launching capabilities of ten nations. A few hundred satellites are currently operational, whereas thousands of unused satellites and satellite fragments orbit the Earth as space debris. A few space probes have been placed into orbit around other bodies and become artificial satellites to the Moon, Venus, Mars, Jupiter and Saturn.
Satellites are used for a large number of purposes. Common types include military (spy) and civilian Earth observation satellites, communication satellites, navigation satellites, weather satellites, and research satellites. Space stations and human spacecraft in orbit are also satellites. Satellite orbits vary greatly, depending on the purpose of the satellite, and are classified in a number of ways. Well-known (overlapping) classes include low Earth orbit, polar orbit, and geostationary orbit.
Satellites are usually semi-independent computer controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, telemetry, attitude control and orbit control.
This text uses material from Wikipedia, licensed under CC BY-SA