Which colors would extraterrestrial civilizations use to transmit signals?: The “magic wavelengths” for optical SETI

Narusawa, S.; Aota, Tatusya; Kishimoto, Ryo

doi:10.1016/j.newast.2017.10.003

Cited by 6 publications

(8 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The application to beacons in SETI is clear; indeed Schelling (1960) cited the work of Cocconi and Morrison (1959) and their choice of the 21-cm line of hydrogen as an example of an interstellar focal point. Since then, many ‘magic frequencies’ (Tarter et al , 1980) and other Schelling points have been suggested in SETI, spanning a range of potential places, frequencies, signal forms and times to search signals (see Drake and Sagan, 1973; Kardashev, 1979; Blair et al , 1992; Blair and Zadnik, 1993; Gindilis et al , 1993; Weber, 1995; Morrison, 2017; Narusawa et al , 2018, for some examples in frequency space).…”

Section: Introductionmentioning

confidence: 99%

Planck frequencies as Schelling points in SETI

Wright¹

2020

International Journal of Astrobiology

View full text Add to dashboard Cite

In SETI, when searching for ‘beacons’ – transmissions intended for us and meant to get our attention – one must guess the appropriate frequency to search by considering what frequencies would be universally obvious to other species. This is a well-known concept in game theory, where such solutions to a non-communicative cooperative game (such as a mutual search) are called ‘Schelling points’. It is noteworthy, therefore, that when developing his eponymous units, Planck called them ‘natural’ because they ‘remain meaningful for all times and also for extraterrestrial and non-human cultures’. Here, I apply Planck's suggestion in the context of Schelling points in SETI with a ‘Planck Frequency Comb’, constructed by multiplying the Planck energy by integer powers of the fine structure constant. This comb includes a small number of frequencies in regions of the electromagnetic spectrum where laser and radio SETI typically operates. Searches might proceed and individual teeth in the comb, or at many teeth at once, across the electromagnetic spectrum. Indeed, the latter strategy can be additionally justified by the transmitter's desire to signal at many frequencies at once, to improve the chances that the receiver will guess one of them correctly. There are many arbitrary and anthropocentric choices in this comb's construction, and indeed one can construct several different frequency combs with only minor and arbitrary modifications. This suggests that it may be fruitful to search for signals arriving in frequency combs of arbitrary spacing. And even though the frequencies suggested here are only debatably ‘better’ than others proposed, the addition of the Planck Frequency Comb to the list of ‘magic frequencies’ can only help searches for extraterrestrial beacons.

show abstract

Section: Introductionmentioning

confidence: 99%

Planck frequencies as Schelling points in SETI

Wright¹

2020

International Journal of Astrobiology

View full text Add to dashboard Cite

show abstract

“…In many cases, while highlighting our extremely Cartesian view of reality, it has been assumed that mathematics -in their anthropocentric version-are the universal language (Cocconi and Morrison, 1959) and that aliens would hold a vision of the world supported in similar pillars as our concept of colour (Narusawa, et al, 2018) or that they would also enjoy similar behavioural aspects such as ethics and morals (Peters, 2018;Szendy, 2013). This incessant search for similarities is what gets ripped to shreds in films like Annihilation (Garland, 2018), where ontological certainties taken from the scientific discourse of biology disappear in the Shimmer, a quarantine ward where an alien presence seems to have altered life's own logic.…”

Section: An Approach To the Communicational Problems With Aliens In Contemporary Filmsmentioning

confidence: 99%

We come in Peace! (Well, do they?): Human Communicative Fears in Films of an Extra-terrestrial Nature

Dow

Uribe-Jongbloed

Aguilar-Rodríguez

2021

kepes

View full text Add to dashboard Cite

Extra-terrestrial beings always have the potential to alter ‘the world as we know it.’ Whenever they appear in film or television, there is a debate about the possibility that we have, as human beings, to communicate with them. Linguistics and semiotics become keyelements in our attempt to bridge the cultural gap. Be it through mathematics, music or technological gadgets, these films only mimic the uncertainty that arises from all types of interculturalcontact. The fear is always the misinterpretation that can turn a ‘We come in peace’ into a fully-fledged war. This article starts from a general review of 138 films from the decade 2007-2017 to recognize the main points present in their narrative, which shows that hostile conflict remains the main theme. Then it provides an interpretive analysis of the films to describe the type of communication fears that exist incontemporary films, taking a special look at Avatar (Cameron, 2009), Arrival (Villeneuve, 2016) and District 9 (Blomkamp, 2009) as the main representations of our current understanding of communication difficulties. The humanization of extra-terrestrial beings to establish communication with them becomes an inverse representation of the dehumanization of the other, the enemy, as depicted by certain sectors of society and a few recently elected governments, with whom it is difficult to establish mechanisms of communication and dialogue.

show abstract

“…The secondary laser lines, as discussed by Narusawa et al (2018), are applicable in case the primary Nd:YAG choice is strongly disfavored. For example, a wavelength of 393.8 nm close to the CaK line can be produced with a sum frequency generation of YAG(R 2 →X 3 ) plus the second harmonic of YAG(R 1 →Y 5 ) ( Table 1).…”

Section: Fraunhofer Lines Versus Laser Linesmentioning

confidence: 99%

“…It has recently been argued, from a laser engineering point of view, that the optimal transmitter is a solidstate high power laser such as Neodymium Yttrium Aluminum Garnet (Nd:YAG) or Neodymium Yttrium Lithium Fluoride (Nd:YLF) (Narusawa et al 2018). These can be operated in both pulsed and continuous michael@hippke.org mode.…”

Section: Introductionmentioning

confidence: 99%

Interstellar communication: The colors of optical SETI

Hippke

2018

J Astrophys Astron

View full text Add to dashboard Cite

It has recently been argued from a laser engineering point of view that there are only a few magic colors for optical SETI. These are primarily the Nd:YAG line at 1,064 nm and its second harmonic (532.1 nm). Next best choices would be the sum frequency and/or second harmonic generation of Nd:YAG and Nd:YLF laser lines, 393.8 nm (near Fraunhofer CaK), 656.5 nm (Hα) and 589.1 nm (NaD2). In this paper, we examine the interstellar extinction, atmospheric transparency and scintillation, as well as noise conditions for these laser lines. For strong signals, we find that optical wavelengths are optimal for distances d kpc. Nd:YAG at λ = 1,064 nm is a similarly good choice, within a factor of two, under most conditions and out to d 3 kpc. For weaker transmitters, where the signal-to-noise ratio with respect to the blended host star is relevant, the optimal wavelength depends on the background source, such as the stellar type. Fraunhofer spectral lines, while providing lower stellar background noise, are irrelevant in most use cases, as they are overpowered by other factors. Laser-pushed spaceflight concepts, such as "Breakthrough Starshot", would produce brighter and tighter beams than ever assumed for OSETI. Such beamers would appear as naked eye stars out to kpc distances. If laser physics has already matured and converged on the most efficient technology, the laser line of choice for a given scenario (e.g., Nd:YAG for strong signals) can be observed with a narrow filter to dramatically reduce background noise, allowing for large field-of-view observations in fast surveys.

show abstract

Which colors would extraterrestrial civilizations use to transmit signals?: The “magic wavelengths” for optical SETI

Cited by 6 publications

References 19 publications

Planck frequencies as Schelling points in SETI

Planck frequencies as Schelling points in SETI

We come in Peace! (Well, do they?): Human Communicative Fears in Films of an Extra-terrestrial Nature

Interstellar communication: The colors of optical SETI

Contact Info

Product

Resources

About