Down on the ground, death equals stillness—but not in space. Abandoned satellites are prone to tumble in unpredictable ways, and an ESA project with the Astronomical Institute of the University of Bern sought to better ...
Space Exploration
Nov 24, 2023
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41
Researchers are using a new AI tool to detect icebergs in the Southern Ocean. This is the first step in being able to track the complete life cycle of most icebergs across Antarctica from satellite data. The study, "Unsupervised ...
Earth Sciences
Nov 24, 2023
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1
A pair of radar experts at Swedish Defense Research working with a meteorologist from the Swedish Meteorological and Hydrological Institute has found evidence suggesting that the reason the Ukrainian military was able to ...
You may not realize it, but the Doppler effect is everywhere in our lives, from tracking the speed of cars with radar to locating satellites in the sky. It's all about how waves change their frequency when a source (like ...
Optics & Photonics
Oct 20, 2023
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321
Research testing new technology to more effectively locate polar bear dens across the Arctic is showing promising results. Researchers from Simon Fraser University and Brigham Young University (BYU), collaborating with Polar ...
Ecology
Oct 18, 2023
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25
Understanding how hailstorm frequency has changed over time can help us build resilience against future hail events.
Earth Sciences
Oct 12, 2023
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12
In the aftermath of Super Typhoon Lekima, which struck mainland China in early August 2019, a number of bird species were recorded in places they had never been seen before. A new study reveals the likely reason behind how ...
Earth Sciences
Sep 27, 2023
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60
Solar eclipses can have a noticeable impact on the structure and dynamics of Earth's upper atmosphere—the ionosphere. This is primarily due to the sudden reduction in solar radiation reaching the Earth's atmosphere during ...
Planetary Sciences
Sep 26, 2023
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0
With its crushing atmospheric pressure, clouds of sulfuric acid, and searing surface temperature, Venus is an especially challenging place to study. But scientists know that observing its surface can provide key insights ...
Planetary Sciences
Sep 19, 2023
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31
Following the devastating earthquake that struck Morocco on 8 September, satellite data have been made available through the International Charter "Space and Major Disasters" to help emergency response teams on the ground.
Planetary Sciences
Sep 14, 2023
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4
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
