Spring snow, sparkling in the sun, can reveal more than just good skiing conditions
One might think that snow, of all things, is easy to describe: it is cold, white and covers the landscape like a blanket. What else is there to say about it?
One might think that snow, of all things, is easy to describe: it is cold, white and covers the landscape like a blanket. What else is there to say about it?
Earth Sciences
Apr 25, 2024
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To study living organisms at ever smaller length scales, scientists must devise new techniques to overcome the so-called diffraction limit. This is the intrinsic limitation on a microscope's ability to focus on objects smaller ...
Biotechnology
Apr 22, 2024
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If you explore the night sky it won't be long before you realize there is a lot of dust and gas up there. The interstellar dust between the stars accounts for 1% of the mass of the interstellar medium but reflects 30% of ...
Astronomy
Mar 1, 2024
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This image from the NASA/ESA Hubble Space Telescope is teeming with color and activity. It features a relatively close star-forming region known as IRAS 16562-3959, which lies within the Milky Way about 5,900 light-years ...
Astronomy
Feb 17, 2024
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This new NASA Hubble Space Telescope view shows the globular cluster NGC 2298, a sparkling collection of thousands of stars held together by their mutual gravitational attraction. Globular clusters are typically home to older ...
Astronomy
Feb 14, 2024
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The way astronomers study planets in our own solar system is surprisingly similar to the way they study exoplanets, despite the latter being orders of magnitude more distant. The key is spectroscopy—examining the wavelengths ...
Planetary Sciences
Dec 18, 2023
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Using 3D printing and porous silicon, researchers at the University of Illinois Urbana-Champaign have developed compact, visible wavelength achromats that are essential for miniaturized and lightweight optics. These high-performance ...
Optics & Photonics
Dec 9, 2023
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Astronomers have known for decades that the universe is expanding. When they use telescopes to observe faraway galaxies, they see that these galaxies are moving away from Earth.
Astronomy
Nov 15, 2023
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Lidar technology improvements will help NASA scientists and explorers with remote sensing and surveying, mapping, 3D-image scanning, hazard detection and avoidance, and navigation.
Space Exploration
Oct 25, 2023
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A state-of-the-art imaging spectrometer, which will measure the greenhouse gases methane and carbon dioxide from space, moved closer to launch this month after being delivered to a clean room at Planet Labs PBC (Planet) in ...
Planetary Sciences
Sep 14, 2023
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In physics, the wavelength of a sinusoidal wave is the spatial period of the wave – the distance over which the wave's shape repeats. It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves. Wavelength is commonly designated by the Greek letter lambda (λ). The concept can also be applied to periodic waves of non-sinusoidal shape. The term wavelength is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids.
Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths.
Examples of wave-like phenomena are sound waves, light, and water waves. A sound wave is a periodic variation in air pressure, while in light and other electromagnetic radiation the strength of the electric and the magnetic field vary. Water waves are periodic variations in the height of a body of water. In a crystal lattice vibration, atomic positions vary periodically in both lattice position and time.
Wavelength is a measure of the distance between repetitions of a shape feature such as peaks, valleys, or zero-crossings, not a measure of how far any given particle moves. For example, in waves over deep water a particle in the water moves in a circle of the same diameter as the wave height, unrelated to wavelength.
This text uses material from Wikipedia, licensed under CC BY-SA