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The apparent change in the wavelength of waves due to the relative movement of the source of the waves relative to the observer.
A group of two (or more) stars that appear to the naked eye to be one, but can be separated into two with a powerful enough instrument.
Doppler effect Any motion-induced change in the observed wavelength (or frequency) of a wave.
The Doppler effect (or Doppler shift) is an increase or decrease in the wavelength of the radiation emitted by an object, as observed from Earth, as the object moves relative to the observer.
Doppler effect (C.J.Doppler)
The apparent change in wavelength of sound or light caused by the motion of the source, observer or both. Waves emitted by a moving object as received by an observer will be blueshifted (compressed) if approaching, redshifted (elongated) if receding.
~ -- The effect on frequency imposed by relative motion between transmitter and receiver. See Chapter 6.
Downlink -- Signal received from a spacecraft.
DSOT -- Data System Operations Team, part of the DSMS staff.
the apparent change in wavelength of sound or light emitted by an object in relation to an observer's position. An object approaching the observer will have a shorter wavelength (blue) while an object moving away will have a longer (red) wavelength.
The apparent change in wavelength of radiation due to relative motion between the source and the observer along the line of sight.
A change in the wavelength of radiation due to relative radial motion of the source and the observer.
Double Galaxy Method ...
~ - Change in frequency of a wave (light, sound, etc.) due to the relative motion of source and receiver. Approaching objects have their wavelengths shortened. Receding objects have emitted wavelengths lengthened.
~. The change in frequency (or wavelength) of light (or other radiation) caused by the motion of an object or the observer. An object receding from an observer would exhibit a frequency shift toward a lower frequency (red shift) and vice-versa.
A measurable shift in the wavelength of a traveling wave caused by the relative motion of the source and observer.
~ - The change in the frequency of a wave (such as electromagnetic radiation) caused by the motion of the source and observer toward or away from each other ...
(a) The alteration in frequency of electromagnetic radiation due to relative motion between the source and observer.
(b) An apparent change in the frequency of a wave motion, caused by relative motion between the source and the observer.
~- change in the observed frequency of sound or radiation that takes place when the observer and the source are moving relative to each other
Dorsum- a ridge
Double-star system- a system of two stars in orbit around each other ...
Another thing that you can get from an absorption or emission spectrum is the velocity of the object producing the spectrum. This is due to the Doppler effect. This is the same effect you experience when an ambulance or a train passes by.
The Doppler effect refers to the apparent shift in the wavelength (and frequency) of a wave when there is relative motion between the source or emitter of the wave and an observer. A common example of this effect is the sound made by a passing ambulance.
The Doppler Effect
You will know the Doppler effect as the falling note of a car or train horn as it approaches, passes, and then goes away from you.
The Doppler Effect
S-4A-3 Rotating Galaxies and Dark Matter
 Doppler effect for a moving black body
The Doppler effect is the well known phenomenon describing how observed frequencies of light are "shifted" when a light source is moving relative to the observer.
The change in the wavelength of sound or light waves caused when the object emitting the waves moves toward or away from the observer; also called Doppler Shift.
~ Apparent change in wavelength of the radiation from a source due to its relative motion away from or towards the observer.
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~ - (n.)
The shift in wavelength of light that is caused by relative motion between the source of light and the observer. The Doppler shift, Deltagamma, is defined as the difference between the observed and rest (laboratory) wavelengths for a given spectral line.
The ~ is the apparent difference between the frequency at which sound or light waves leave a source and that at which they reach an observer, caused by relative motion of the observer and the wave source.
But during the oscillations, matter and radiation also move into and out of the compressed region, thus inducing a Doppler effect and a consequent increase (or decrease) in the observed temperature according to whether the fluid is moving towards (or away from) the observer.
BL Lacertae object blueshift A wavelength shift toward shorter wavelengths due to approach of the emitting object; see Doppler effect. blue stellar object Non-radio-emitting quasar identified by its bright ultraviolet radiation and pronounced redshift.
Discovery of the 'Doppler Effect' by Austrian physicist and mathematician, Christian Doppler.
In the case of an emitting gas, for example, those molecules which are approaching the observer as they emit quanta of radiant energy will, because of the Doppler effect, appear to send out a train of waves of slightly shorter wavelength than that characteristic of a stationary molecule, ...
pulse Doppler radar (NASA Thesaurus) A pulse radar system which utilizes the Doppler effect for obtaining information about the target (not including simple resolution from fixed targets).
The Doppler shift (or Doppler Effect) is an increase or decrease in wavelength as the object emitting the wave moves relative to the observer.
This effect, called the ~, is similar to what happens to sound waves emitted from a moving object.
But there is also a way of measuring a star's movement by using the ~. If you ever stand on the side of a highway while a car rushing by blows its horn, you'll notice a change of pitch.
The velocity of the material flowing in these loops can be determined using the "~." The light from material moving toward us is shifted toward the blue end of the spectrum while light from material moving away from us is shifted toward the red end.
As the spectra of these stars vary due to the ~, they are called spectroscopic binaries. Radial velocity studies can be used to estimate the masses of the stars, and some orbital elements, such as eccentricity and semimajor axis.
In atomic physics, Doppler broadening is the broadening of spectral lines due to the ~ in which the heat movement of atoms or molecules shifts the apparent frequency of each emitter....
of the fuel's neutron cross-section.
(The "~" causes shifts in the wavelengths of light as a result of motion toward or away from the observer.) Assume a single star.
Its rotational period is 59 days, as determined by radar measurements from the Earth using the ~. The ratio of the rotational period to the orbital period is 2/3, and is an example of more complicated tidal locking than for the Earth-Moon system.
Using the ~, which reddens the light from receding objects, astronomers measured a redshift of 4.5, corresponding to a distance of 11 billion years.
Slipher's spectrum showed the light from Andromeda was "blueshifted", which meant its light waves were compressed by the ~ to appear more "blue" as a consequence of its motion towards our solar system.
The light is redshifted because of the ~ not because its doing work against gravity and losing energy; that would be gravitational redshift. More specifically it's the Relativistic ~.
Blue shift: Apparent shortening of the wavelength due to ~, of radiation received from a source in motion toward the observer.
Brown Dwarf: Either a supermassive planet or a failed star, a brown dwarf has insufficient mass to sustain nuclear fusion.
The technique employed involves the detection through the ~ of periodic variations in the motion of parent stars which is attributed to the presence of planets. This allows the mass and orbital characteristics of the unseen planets to be determined.
Tiny gravitational pulls of the moon on the spacecraft, equal to just one part in a trillion, could modulate the carrier signal by changing its frequency. These variations are caused by the ~ - a change in the wavelength of radiation emitted by an object as it moves closer (shorter ...
Here are some web pages related to the nature of light: All About Spectra and related links on Spectral Emission Lines and The ~, and X-rays and Gamma Rays ...
STIS relies on the ~ to measure gas velocity rapidly increasing to nearly 240 miles per second within 26 light years of the center of M84, a galaxy in the Virgo Cluster about 50 million light years away.
created an experiment involving an alternate means for measuring the velocity of their rocket as it flew. Through the experiment, the team used the ~ to determine the rocket's velocity using radio transmissions. The rocket reached an altitude of 3,779 feet.
There are two main methods of detecting extrasolar planets, which are too faint to be detected by present conventional optical means. The first involves measuring the displacement in the parent star's spectral lines due to the ~ induced by the planet orbiting the star and moving it ...
Such a relative motion causes a ~ on the light (or radio waves) coming into the telescope. This can cause the frequency of the emission (or absorption) line that you are looking at to shift.
This occurs as the wavelengths of light stretch as an object moves away (as opposed to being squashed by an approaching object), similar to the familiar ~ on sound waves.
Theory of the measurement of vibration using Laser ~ are researched and reference Laser Doppler optical system are designed.
In these systems the spectrum is dominated by one of the two stars. Spectroscopic binary systems are usually detected due to the movement of the emission and absorption lines in the observed spectrum, caused by the ~ as the stars move in their orbit.
From this he inferred that the galaxies exhibiting such "red shifts" were moving away from Earth, a conclusion he based on the ~. This effect, discovered by Austrian mathematician and physicist Christian Doppler in 1842, arises from the relative motion between a source and an observer.
are moving away from us will become shifted towards red, and may shift so far that it is no longer visible at all. (Note: You hear the same effect when an ambulance passes you, and the pitch of the siren gets lower as the ambulance travels away from you; this effect is called the ~).
See also: What is the meaning of Astro, Earth, Star, Orbit, Sun?