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troutman · 10-25-2016, 03:33 PM

Discovery of Peculiar Periodic Spectral Modulations in a Small Fraction of Solar-type Stars

http://iopscience.iop.org/article/10...ce.cld.iop.org

A Fourier transform analysis of 2.5 million spectra in the Sloan Digital Sky Survey was carried out to detect periodic spectral modulations. Signals having the same period were found in only 234 stars overwhelmingly in the F2 to K1 spectral range. The signals cannot be caused by instrumental or data analysis effects because they are present in only a very small fraction of stars within a narrow spectral range and because signal-to-noise ratio considerations predict that the signal should mostly be detected in the brightest objects, while this is not the case. We consider several possibilities, such as rotational transitions in molecules, rapid pulsations, Fourier transform of spectral lines, and signals generated by extraterrestrial intelligence (ETI). They cannot be generated by molecules or rapid pulsations. It is highly unlikely that they come from the Fourier transform of spectral lines because too many strong lines located at nearly periodic frequencies are needed. Finally, we consider the possibility, predicted in a previous published paper, that the signals are caused by light pulses generated by ETI to makes us aware of their existence. We find that the detected signals have exactly the shape of an ETI signal predicted in the previous publication and are therefore in agreement with this hypothesis. The fact that they are only found in a very small fraction of stars within a narrow spectral range centered near the spectral type of the Sun is also in agreement with the ETI hypothesis. However, at this stage, this hypothesis needs to be confirmed with further work. Although unlikely, there is also a possibility that the signals are due to highly peculiar chemical compositions in a small fraction of galactic halo stars.

https://seti.berkeley.edu/bl_sdss_seti_2016.pdf

The one in 10,000 objects with unusual spectra seen by Borra and Trottier are certainly worthy of additionalstudy. However, extraordinary claims require extraordinary evidence. It is too early to unequivocally attributethese purported signals to the activities of extraterrestrial civilizations.

10-25-2016, 03:33 PM	#2857
troutman Unfrozen Caveman Lawyer Join Date: Oct 2002 Location: Crowsnest Pass Exp:	Discovery of Peculiar Periodic Spectral Modulations in a Small Fraction of Solar-type Stars http://iopscience.iop.org/article/10...ce.cld.iop.org A Fourier transform analysis of 2.5 million spectra in the Sloan Digital Sky Survey was carried out to detect periodic spectral modulations. Signals having the same period were found in only 234 stars overwhelmingly in the F2 to K1 spectral range. The signals cannot be caused by instrumental or data analysis effects because they are present in only a very small fraction of stars within a narrow spectral range and because signal-to-noise ratio considerations predict that the signal should mostly be detected in the brightest objects, while this is not the case. We consider several possibilities, such as rotational transitions in molecules, rapid pulsations, Fourier transform of spectral lines, and signals generated by extraterrestrial intelligence (ETI). They cannot be generated by molecules or rapid pulsations. It is highly unlikely that they come from the Fourier transform of spectral lines because too many strong lines located at nearly periodic frequencies are needed. Finally, we consider the possibility, predicted in a previous published paper, that the signals are caused by light pulses generated by ETI to makes us aware of their existence. We find that the detected signals have exactly the shape of an ETI signal predicted in the previous publication and are therefore in agreement with this hypothesis. The fact that they are only found in a very small fraction of stars within a narrow spectral range centered near the spectral type of the Sun is also in agreement with the ETI hypothesis. However, at this stage, this hypothesis needs to be confirmed with further work. Although unlikely, there is also a possibility that the signals are due to highly peculiar chemical compositions in a small fraction of galactic halo stars. https://seti.berkeley.edu/bl_sdss_seti_2016.pdf The one in 10,000 objects with unusual spectra seen by Borra and Trottier are certainly worthy of additionalstudy. However, extraordinary claims require extraordinary evidence. It is too early to unequivocally attributethese purported signals to the activities of extraterrestrial civilizations. Last edited by troutman; 10-25-2016 at 03:36 PM.