Acta Astronautica: Contact with Extraterrestrial Civilizations. A Scenario Analysis.

The issue is absolutely serious. Very. Researchers analyze in deep the ET next Contac and hypotize the scenario of the most important event in the history of humanity, so the possibility of contact merits our ongoing attention.
Searches to date of the solar system are sufficiently incomplete that we cannot rule out the possibility that non-terrestrial artifacts are present and may even be observing us...

Abstract
While humanity has not yet observed any extraterrestrial intelligence (ETI), contact with ETI
remains possible. Contact could occur through a broad range of scenarios that have varying
consequences for humanity. However, many discussions of this question assume that contact
will follow a particular scenario that derives from the hopes and fears of the author. In this
paper, we analyze a broad range of contact scenarios in terms of whether contact with ETI would
benefit or harm humanity. This type of broad analysis can help us prepare for actual contact with
ETI even if the details of contact do not fully resemble any specific scenario.

Seth D. Baum,1 Jacob D. Haqq-Misra,2 & Shawn D. Domagal-Goldman3
1. Department of Geography, Pennsylvania State University.
2. Department of Meteorology, Pennsylvania State University
3. NASA Planetary Science Division

The complete document in Pdf.
arxiv.org...

2.2 Interstellar communication.
Even if ETI exist in the nearby galactic vicinity, this does not necessarily imply that communication with them will be possible or straightforward. One major challenge is selecting
the frequency at which to broadcast and listen [24]. The electromagnetic spectrum consists of a
continuum of wavelengths for communication that includes radio, microwave, infrared, visible,
ultraviolet, and x-ray bands. Searching this entire range is a monumental and nearly impossible
task, so we choose particular wavelengths that seem more probable for interstellar
communication. For example, the 21 cm hyperfine transition of neutral hydrogen was the first
suggestion for a communication wavelength [1]. The water hole at a wavelength of 18 cm is
another popular choice for SETI [24], and recent analysis has suggested that we shift our focus
toward higher frequencies [25]. However, because there is an infinite number of wavelengths for
interstellar communication, we must acknowledge the possibility that ETI may be transmitting or
listening at wavelength ranges that we have not yet considered. The possibility also remains that
ETI do not use electromagnetic radiation for communication but instead have discovered some
other method (possibly something more efficient or effective) for exchanging information across
astronomical distances.

Seems that we see in the wrong way... SETI.

That is the problem I have with SETI and other form of trying to communicate with ETI is that they may have evolved past the point of radio wave (highly likely) or maybe any other form of commuication that we know of so far.

How do we know that they haven't tried beaming a certain signal at us that we yet do not have? We wouldn't even know its there, same thing maybe happening with SETI's radio telescope array.

All in all great read. I like the graphs showing the possible difference between the ETI. Good work.

-SAP-