War, budget cuts, a pandemic and a crash: For all its trials, Europe's ExoMars mission might be more deserving of the name Perseverance than NASA's Martian rover.
Space Exploration
Feb 3, 2023
0
45
Birds including swallows and martins—known as aerial insectivores—control insect populations and insect-borne disease and provide hundreds of millions of dollars' worth of pest control for agriculture. But these feathered ...
Ecology
Jan 27, 2023
0
93
With diminishing ice one of the biggest casualties of our warming world, it's imperative that accurate measurements continue to be made for scientific research and climate policy, as well as for practical applications such ...
Planetary Sciences
Jan 20, 2023
1
6
Doppler radar, the Consumer Price Index, quarterback rating—these and many other measuring tools have refined the way performance is both documented and predicted in weather, the economy and sports.
Economics & Business
Jan 18, 2023
0
6
With a transmitter less powerful than a microwave oven, a team of scientists and engineers has used the National Science Foundation's Green Bank Telescope (GBT) and Very Long Baseline Array (VLBA) to make the highest-resolution ...
Planetary Sciences
Jan 10, 2023
0
49
Meet the scientific heart of the Surface Water and Ocean Topography mission, which will see Earth's water in higher definition than ever before.
Planetary Sciences
Dec 13, 2022
0
97
Predicting snowfall from winter storms is tricky, in no small part because heavy snow and regions of mixed precipitation look very similar in weather radar imagery. Mixed precipitation falls as a blend of rain, freezing rain, ...
Earth Sciences
Dec 1, 2022
0
36
A new enhanced 3D radar image offer a greatly improved view of the interior of the Martian north polar cap, according to a paper led by Planetary Science Institute Senior Scientist Nathaniel Putzig.
Space Exploration
Nov 28, 2022
0
91
On July 31, 2013 a constellation of US defense satellites saw a streak of light over South Australia as a rock from outer space burned through Earth's atmosphere on its way to crash into the ground below.
Astronomy
Nov 26, 2022
0
36
Scientists at the Max Planck Institute of Animal Behavior in Konstanz, Germany, and the Netherlands Institute of Ecology GPS tracked Arctic migratory geese in Germany, Denmark, and the Netherlands over the New Year period ...
Plants & Animals
Nov 25, 2022
0
209
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
