Free Doppler Shift Essay Sample
The Doppler Effect is a phenomenon that happens when the source of the wave and the observer is moving closer or away from each other. In the case of light, when the source and the observer moves closer to each other, the light as observed will have shorter wavelength (blueshifted) while when the source and the observer moves away from each other, the light as observed will have longer wavelength (redshifted).
In the situations A to D, only situation C experiences a light shifted to a shorter wavelength, hence, the light is blueshifted. This is because the source of the light, which is a star, is moving closer to the observer.
On the other hand, only situation B experiences a light shifted to a longer wavelength, hence, the light is redshifted because the star is moving away from the observer.
There are two situations where the light observed is not shifted to a shorter nor longer wavelength. In situation A, the star and the observer is stationary, thus, the relative distance between the two does not change. In addition, in situation D, even as the star moves perpendicular to the observer’s line of sight, the distance between them is not changing. Thus, both situations A and D have light that is not shifted to a shorter nor longer wavelength.
In the case where the solar system moves toward a group of stars, namely star A, star B, and star C, the light from all of the stars will be blueshifted. Therefore, none will emit a redshifted light. Furthermore, none will emit a light with wavelength that is not shifted.
The movement of an object can be determined by examining its absorption spectra. Thus, I agree with student 2. The color of the stars is not enough to determine its movement.
Since it was stated that the three absorption line spectra corresponds to a star that is relatively not moving, a star that is relatively moving closer, and a star that is relatively moving away from the observer, we can infer which star are they by arranging the absorption line spectra according to the shifting of the lines. Thus, star C is the star moving towards the observer while star B is the star moving away from the observer.
Additionally, the absorption line spectra can also be used to infer the speed of the star as it moves relative to the observer. In the absorption line spectra given, it was stated that star F is stationary relative to the observer. Thus, since star E has the greatest shift, we can say that star E is moving the fastest relative to the observer. Moreover, it can also be inferred that star E is moving away from the observer since the shift is to the right.
On the other hand, star G is the star with the slowest movement because the absorption line spectra displays the least shift. Moreover, the shift is to the left, thus, the star is moving closer to the observer.
For the stars H to L, it was stated that an important line in the absorption spectra of stars at rest occurs at a wavelength of 656 nm. Since stars H and L displayed that this important absorption line is measured at shorter wavelengths, then both stars H and L emit light that is blueshifted. On the other hand, stars I and K is observed to have this important absorption line at longer wavelengths, both stars I and K emit light that is redshifted. Furthermore, the star with the greatest shift relative to the observer is star L. This is because it had the greatest deviation from the important absorption line of stars at rest. In addition, this star is observed to be moving closer to the observer. Lastly, star L must also be the star with the greatest movement because it displayed the greatest shift.
The radio signals received by planet A will have longer wavelengths than the radio signals received by planet B. This is because the space probe is moving away from planet A and closer to planet B. However, even if the space probe is moving closer to both stars B and E, relatively, both stars will observe the space probe to be moving at a similar speed. Thus, the shift of the wavelength of the radio signals will be similar as observed by planets B and E.