The discussion centers on the feasibility of detecting radio waves from technological civilizations located 1000 light years away. Participants agree that while radio waves do lose intensity over distance, they can still be detected if sufficiently powerful. The conversation highlights the limitations of current observational astronomy and the possibility that advanced civilizations may utilize alternative communication methods beyond radio. Furthermore, the lack of detected signals does not imply the absence of such civilizations, as they may not be broadcasting or may be using more efficient technologies.
PREREQUISITESAstronomers, astrophysicists, science fiction writers, and anyone interested in the search for extraterrestrial intelligence and the implications of advanced civilizations in the universe.
Chronos said:The frequency thing is a little dicey, but broadcasting at the 21 cm wavelength would be a no-brainer for any advanced civilization
Yaaks said:On the Contrary, Electromagnetic waves of all freq. (including Radio waves) undergo Red-Shift as Space expands (however miniscule)..
21 cm is the frequency of neutral hydrogen. An advanced civilization would realize broadcasts at this frequency would have an excellent chance of being detected by other radio astronomers - who would naturally spend a lot of time mapping the distribution of neutral hydrogen.Pengwuino said:Whys that?
Well!,, i was refrerring to the Universe as a whole, Generally speaking!...GOD__AM said:There is no red shift due to expansion from our own galaxy.
To clarify: There is a relationship between redshift and cosmological distance. The more distant an object, the more it is redshifted. The conventional explanation is that the universe is expanding and therefore all non-gravitationally-bound objects are receding from one another. This may or may not be true. If it is true, it in no way falsifies the concept that some objects have intrinsic redshifts.Chronos said:Expansion is not the only factor influencing redshift, but is the most dominant factor. There is no other viable explanation for high redshift. If redshift was intrinsic, we should see high redshift objects superimposed over low redshift objects all over the sky. But not a single, incontrovertable observation of such has been found.
and i believe its true, since there is overwhelming observational evidence that the the expansion is accelerating over time...turbo-1 said:To clarify: There is a relationship between redshift and cosmological distance. The more distant an object, the more it is redshifted. The conventional explanation is that the universe is expanding and therefore all non-gravitationally-bound objects are receding from one another. This may or may not be true. If it is true, it in no way falsifies the concept that some objects have intrinsic redshifts.