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Largest collection of free-floating planets found in the Milky Way

Using observations and archival data from several of NSF's NOIRLab's observatories, together with observations from telescopes around the world and in orbit, astronomers have discovered at least 70 new free-floating planets—planets ...

Image: Hubble views a galaxy with an explosive past

In this image, the NASA/ESA Hubble Space Telescope captures a side-on view of NGC 3568, a barred spiral galaxy roughly 57 million light-years from the Milky Way in the constellation Centaurus. In 2014 the light from a supernova ...

New space telescope to uncover secrets of Universe's origins

The NASA-led James Webb Space Telescope, which includes hardware designed and built at UCL and which will image the very first stars to shine in the Universe, is scheduled to be launched into space later this month.

Is Europe entering a golden age of astronomy?

Groundbreaking discoveries about gravitational waves, black holes, cosmic rays, neutrinos and other areas of cutting-edge astronomy may soon become more frequent due to the convergence of two major communities of astronomers ...

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Wavelength

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.

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