Related topics: nasa

Astronomers estimate Titan's largest sea is 1,000-feet deep

Far below the gaseous atmospheric shroud on Saturn's largest moon, Titan, lies Kraken Mare, a sea of liquid methane. Cornell University astronomers have estimated that sea to be at least 1,000-feet deep near its center—enough ...

Satellite to track rising seas as climate warms

An Earth-observation satellite developed by European and US space agencies set to lift off Saturday will measure sea level rise, tracking changes threatening to disrupt tens of millions of lives within a generation.

Telecom transmitter masts can be used to predict rain

Rain showers are difficult to predict, as they usually develop into a downpour within half an hour, resulting in flooding. Much depends on being able to spot time, location and precipitation ahead of time on the radar. The ...

Image: Laguna San Rafael National Park, Chile

Part of the Laguna San Rafael National Park, located on the Pacific coast of southern Chile, is pictured in this image captured by the Copernicus Sentinel-2 mission.

Radar developed for rapid rescue of buried people

When someone is buried by an avalanche, earthquake or other disaster, a rapid rescue can make the difference between life and death. The Fraunhofer Institute for High Frequency Physics and Radar Techniques FHR has developed ...

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Radar

Radar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for radio detection and ranging. The term has since entered the English language as a standard word, radar, losing the capitalization. Radar was originally called RDF (Radio Direction Finder, now used as a totally different device) in the United Kingdom.

A radar system has a transmitter that emits microwaves or radio waves. These waves are in phase when emitted, and when they come into contact with an object are scattered in all directions. The signal is thus partly reflected back and it has a slight change of wavelength (and thus frequency) if the target is moving. The receiver is usually, but not always, in the same location as the transmitter. Although the signal returned is usually very weak, the signal can be amplified through use of electronic techniques in the receiver and in the antenna configuration. This enables radar to detect objects at ranges where other emissions, such as sound or visible light, would be too weak to detect. Radar is used in meteorological detection of precipitation, measuring ocean surface waves, air traffic control, police detection of speeding traffic, and by the military.

This text uses material from Wikipedia, licensed under CC BY-SA