The device consists of a 2 meter-long gently curving arc of alumina a dielectric material , with a series of electrodes fitted at regular intervals along its length. Applying a sinusoidal voltage across each electrode and displacing the phase of the voltage very slightly from one electrode to the next generates a sinusoidally-varying polarization pattern that moves along the device. By carefully adjusting the frequency of the voltage and the phase displacement the researchers say they can make the wave travel at greater than the speed of light.
However no physical quantity of charge travels faster than light speed. One possible use for faster than light radio waves — which are packed into a very powerful wave the size of a pencil point — could be the creation of a new generation of cell phones that communicate directly to satellites, rather than transmitting through relay towers as they now do. Those phones would have more reliable service and would also be more difficult for hackers to intercept, Singleton said.
Speedy radio waves could also revolutionize the computing industry. Data could be transferred more quickly, and if used in semiconductors, it would mean faster caches and the ability to communicate across separate pieces of silicon nearly instantly.
In the health field, faster than light radio waves could be in extremely targeted chemotherapy, where a patient takes the drugs, and the radio waves are used to activate them very specifically in the area around a tumor, Singleton said.
Read the paper on the Polarization Synchrotron. Sources: Current, Geek. The speed of light is a fundamental limit on causality.
No causal signal or information can travel faster. In this case what is travelling faster than light is a phase, but not information. Is this just a quirky thing that happens on a bench or can we someday look forward to FTL Morse code from mars? This article is very confusing as written.
The paragraph about using this phenomenon to speed up data processing in computers clearly indicates that this can be used to convey information faster. Even if only a portion of the wave is moving faster than light speed, that is still significant. Even though the signal itself cannot carry information the signal itself can be the information. Does this radio wave exist?
However, what we are interested in here is the transmission of non-random information from one place to another. To do this, you have to modulate the signal somehow to allow the wave to carry information. Here it gets technical, but suffice it to say that the modulated wave packet travels more slowly than the phase velocity of the wave in question.
It gets very involved with a lot of subtle points. It confuses and trips up many an intelligent physicist. Take a laser pointer, and point it at the moon. The spot of the laser pointer is moving across the lunar landscape at approximately the speed of light! Just thought of another — if you pre-program the audience, you can make a stadium wave move faster than the speed of light too! The speed of light is fast but its not instantaneous.
It would simply arrive before a light based signal did. The phase that this article describes can only transfer information about one part to the Universe to another at the speed of light or less; no faster. This article is very misleading about the wording it uses in addition to the implied result it present.
This article may as well be about the invention of a perpetual motion machine. What the argument boils down to is that Special Relativity dictates that the receiver would get the signal before the transmitter sent it, and can do something to disrupt the signal before it is sent by the transmitter, thus preventing the receiver from getting the signal, etc, etc.
That would obviously violate casuality and create a paradox, which would make the scenario impossible. Can anyone help me find that article? Parts of it got math-y, but it was a very good description of the problem posed by FTL information transfer.
This is the kind or article that you either disregard or perhaps glance through to see how the original informants are trying to mess with their readers mind.
Note that the paper is from , which means that the research has emptied out the possibilities of their setup. The electromagnetic radiation emitted by X-ray tubes generally has a longer wavelength than the radiation emitted by radioactive nuclei. Historically, therefore, an alternative means of distinguishing between the two types of radiation has been by their origin: X-rays are emitted by electrons outside the nucleus, while gamma rays are emitted by the nucleus.
There is overlap between the wavelength bands of photons emitted by electrons outside the nucleus, and photons emitted by the nucleus. Like all electromagnetic radiation, the properties of X-rays or gamma rays depend only on their wavelength and polarization. Gamma rays are very high frequency electromagnetic waves usually emitted from radioactive decay with frequencies greater than 10 19 Hz.
Identify wavelength range characteristic for gamma rays, noting their biological effects and distinguishing them from gamma rays. However, this is not a hard and fast definition, but rather only a rule-of-thumb description for natural processes. Gamma rays from radioactive decay are defined as gamma rays no matter what their energy, so that there is no lower limit to gamma energy derived from radioactive decay.
Gamma decay commonly produces energies of a few hundred keV, and almost always less than 10 MeV. Gamma rays are ionizing radiation and are thus biologically hazardous. They are classically produced by the decay from high energy states of atomic nuclei, a process called gamma decay, but are also created by other processes.
Paul Villard, a French chemist and physicist, discovered gamma radiation in , while studying radiation emitted from radium during its gamma decay. Natural sources of gamma rays on Earth include gamma decay from naturally occurring radioisotopes such as potassium, and also as a secondary radiation from various atmospheric interactions with cosmic ray particles. Some rare terrestrial natural sources that produce gamma rays that are not of a nuclear origin, are lightning strikes and terrestrial gamma-ray flashes, which produce high energy emissions from natural high-energy voltages.
Gamma rays are produced by a number of astronomical processes in which very high-energy electrons are produced. Such electrons produce secondary gamma rays by the mechanisms of bremsstrahlung, inverse Compton scattering and synchrotron radiation. Notable artificial sources of gamma rays include fission such as occurs in nuclear reactors, and high energy physics experiments, such as neutral pion decay and nuclear fusion. Gamma rays have characteristics identical to X-rays of the same frequency—they differ only in source.
They have many of the same uses as X-rays, including cancer therapy. Gamma radiation from radioactive materials is used in nuclear medicine. The distinction between X-rays and gamma rays has changed in recent decades. Originally, the electromagnetic radiation emitted by X-ray tubes almost invariably had a longer wavelength than the radiation gamma rays emitted by radioactive nuclei.
However, with artificial sources now able to duplicate any electromagnetic radiation that originates in the nucleus, as well as far higher energies, the wavelengths characteristic of radioactive gamma ray sources vs.
Thus, gamma rays are now usually distinguished by their origin: X-rays are emitted by definition by electrons outside the nucleus, while gamma rays are emitted by the nucleus. Exceptions to this convention occur in astronomy, where gamma decay is seen in the afterglow of certain supernovas, but other high energy processes known to involve other than radioactive decay are still classed as sources of gamma radiation.
A notable example is extremely powerful bursts of high-energy radiation normally referred to as long duration gamma-ray bursts, which produce gamma rays by a mechanism not compatible with radioactive decay.
These bursts of gamma rays, thought to be due to the collapse of stars called hypernovas, are the most powerful events so far discovered in the cosmos. Bright spots within the galactic plane are pulsars spinning neutron stars with strong magnetic fields , while those above and below the plane are thought to be quasars galaxies with supermassive black holes actively accreting matter.
All ionizing radiation causes similar damage at a cellular level, but because rays of alpha particles and beta particles are relatively non-penetrating, external exposure to them causes only localized damage e. Gamma rays and neutrons are more penetrating, causing diffuse damage throughout the body e.
The most biological damaging forms of gamma radiation occur at energies between 3 and 10 MeV. Privacy Policy. Skip to main content. Electromagnetic Waves. Search for:. The Electromagnetic Spectrum. There is a wide range of subcategories contained within radio including AM and FM radio. Radio waves can be generated by natural sources such as lightning or astronomical phenomena; or by artificial sources such as broadcast radio towers, cell phones, satellites and radar.
AM waves have constant frequency, but a varying amplitude. FM radio waves are also used for commercial radio transmission in the frequency range of 88 to MHz. FM stands for frequency modulation, which produces a wave of constant amplitude but varying frequency.
Information is carried by amplitude variation, while the frequency remains constant. FM radio waves : Waves used to carry commercial radio signals between 88 and MHz. Information is carried by frequency modulation, while the signal amplitude remains constant. Microwaves Microwaves are electromagnetic waves with wavelengths ranging from one meter to one millimeter frequencies between MHz and GHz. Learning Objectives Distinguish three ranges of the microwave portion of the electromagnetic spectrum.
Key Takeaways Key Points The microwave region of the electromagnetic EM spectrum is generally considered to overlap with the highest frequency shortest wavelength radio waves. The microwave portion of the electromagnetic spectrum can be subdivided into three ranges listed below from high to low frequencies: extremely high frequency 30 to GHz , super high frequency 3 to 30 GHz , and ultra-high frequency MHz to 3 GHz.
Microwave sources include artificial devices such as circuits, transmission towers, radar, masers, and microwave ovens, as well as natural sources such as the Sun and the Cosmic Microwave Background.
Microwaves can also be produced by atoms and molecules. They are, for example, a component of electromagnetic radiation generated by thermal agitation.
Key Terms terahertz radiation : Electromagnetic waves with frequencies around one terahertz. Learning Objectives Distinguish three ranges of the infrared portion of the spectrum, and describe processes of absorption and emission of infrared light by molecules.
Key Takeaways Key Points Infrared light includes most of the thermal radiation emitted by objects near room temperature. This is termed thermography, mainly used in military and industrial applications. Key Terms emissivity : The energy-emitting propensity of a surface, usually measured at a specific wavelength. Visible Light Visible light is the portion of the electromagnetic spectrum that is visible to the human eye, ranging from roughly to nm.
Learning Objectives Distinguish six ranges of the visible spectrum. Key Takeaways Key Points Visible light is produced by vibrations and rotations of atoms and molecules, as well as by electronic transitions within atoms and molecules.
This figure shows the visible part of the spectrum, together with the colors associated with particular pure wavelengths. How long does it take for transmissions to get between DS1 and Earth? How often is DS1 in communication with Earth? What are radio waves? How is lag dealt with? More Best Practices ». More Case Studies ». FEC has gained full visibility into its work-in-p More Features ». More How-To Articles ». Address Line 1. Address Line 2. State or Province. Zip or Postal Code.
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