By analyzing the data from ESA's Gaia satellite, Chinese astronomers have detected a new tidal stellar stream in the northern hemisphere, which has a low metallicity and a relatively high energy. The finding was reported ...
Oases are important habitats and water sources for dryland regions, sustaining 10% of the world's population despite taking up about 1.5% of land area. But in many places, climate change and anthropogenic activities threaten ...
Earth Sciences
23 hours ago
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New research finds that modern weather models can accurately predict satellite movements due to the energy emitted and reflected by the Earth. In addition to weather prediction, weather models can also help understand and ...
Earth Sciences
Apr 19, 2024
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Land subsidence is overlooked as a hazard in cities, according to scientists from the University of East Anglia (UEA) and Virginia Tech. Writing in the journal Science, Prof Robert Nicholls of the Tyndall Center for Climate ...
Earth Sciences
Apr 18, 2024
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Tropical marine species venturing into new areas as the climate changes could fall victim to another effect of the phenomenon—as bursts of cold water from the deep sea suddenly kill them.
Plants & Animals
Apr 16, 2024
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California's Death Valley, the driest place in North America, has hosted an ephemeral lake since late 2023. A NASA-led analysis recently calculated water depths in the temporary lake over several weeks in February and March ...
Earth Sciences
Apr 16, 2024
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It's Saturday, which means that in a universe where the arrow of time moves backward, people have to go to work tomorrow. In such a hypothetical universe, Garfield hates Fridays—tough to imagine. This week, we looked at ...
In the early morning of 22 May 2021, a magnitude 7.4 quake rattled China's remote Maduo County on the Tibetan Plateau. It was the most recent in a series of nine earthquakes with a magnitude of 7 or greater since 1997, and ...
Earth Sciences
Apr 11, 2024
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An analysis of building footprints in major US metropolitan areas identifies five different neighborhood types that vary in footprint size, shape, and placement, and which are statistically associated with varying neighborhood ...
Social Sciences
Apr 10, 2024
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A University of California, Irvine-led team reveals a clear link between human-driven climate change and the years-long drought currently gripping southern Madagascar. Their study appears in npj Climate and Atmospheric Science.
Earth Sciences
Apr 9, 2024
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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
