Spreading the net

Carstairs, I. R.

doi:10.1046/j.1468-4004.2002.43626.x

Cited by 3 publications

(2 citation statements)

References 8 publications

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“…Other ways an X-ray binary could have been modified by an advanced civilization have been proposed (Fabian 1977; Corbet 1997; Carstairs 2002). Recently, a remarkable model on how a pulsar's signal may be modulated by an artificial satellite has been proposed (Chennamangalam et al 2015).…”

Section: Discussionmentioning

confidence: 99%

Pulsar positioning system: a quest for evidence of extraterrestrial engineering

Vidal

2017

International Journal of Astrobiology

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Pulsars have at least two impressive applications. First, they can be used as highly accurate clocks, comparable in stability to atomic clocks; secondly, a small subset of pulsars, millisecond X-ray pulsars, provide all the necessary ingredients for a passive galactic positioning system. This is known in astronautics as X-ray pulsar-based navigation (XNAV). XNAV is comparable to GPS, except that it operates on a galactic scale. I propose a SETI-XNAV research program to test the hypothesis that this pulsar positioning system might be an instance of galactic-scale engineering by extraterrestrial beings (section 4). The paper starts by exposing the basics of pulsar navigation (section 2), continues with a critique of the rejection of the extraterrestrial hypothesis when pulsars were first discovered (section 3). The core section 4 proposes lines of inquiry for SETI-XNAV, related to: the pulsar distribution and power in the galaxy; their population; their evolution; possible pulse synchronizations; pulsar usability when navigating near the speed of light; decoding galactic coordinates; directed panspermia; and information content in pulses. Even if pulsars are natural, they are likely to be used as standards by ETIs in the galaxy (section 5). I discuss possible objections and potential benefits for humanity, whether the research program succeeds or not (section 6).

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Section: Discussionmentioning

confidence: 99%

Pulsar positioning system: a quest for evidence of extraterrestrial engineering

Vidal

2017

International Journal of Astrobiology

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“…Now and again, conducting the Search for Extraterrestrial Intelligences (SETI) in X-rays is proposed (Corbet 1997;Carstairs 2002;Hippke & Forgan 2017b). Extraterrestrial intelligences (ETIs) may have several reasons to prefer X-rays.…”

Section: Introductionmentioning

confidence: 99%

Lens Flare: Magnified X-Ray Binaries as Passive Beacons in SETI

Lacki

2020

Preprint

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Low mass X-ray binaries (LMXBs) containing neutron stars are both extremely luminous and compact, emitting up to ∼ 10 6 L within a kilometer-scale boundary layer. This combination allows for easy modulation, motivating X-ray SETI. When X-ray lenses smaller than planets (100-1,000 km) magnify the LMXB boundary layer, it brightens by a factor of several thousand for about a second. In addition, there should be occultation events where the neutron star is blocked out. Passive X-ray lenses could require little maintenance and the LMXB light source itself shines for millions of years, serving as an effective beacon for interstellar communication. A very large number of lenses would be needed to ensure detection from all directions, however, and gathering material to construct them could be very difficult. Avoiding collisions between lenses and aiming them pose additional challenges. Both "lens flares" and eclipses of LMXBs are easily detectable in the Galaxy, although they would be rare events, occurring once per decade. Our X-ray instruments could detect the flares to several Mpc, but it is unlikely they would be observing the LMXB during a flare.

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Lens Flare: Magnified X-Ray Binaries as Passive Beacons in SETI

Lacki

2020

ApJ

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Low-mass X-ray binaries (LMXBs) containing neutron stars are both extremely luminous and compact, emitting up to ∼106 within a kilometer-scale boundary layer. This combination allows for easy modulation, motivating an X-ray Search for Extraterrestrial Intelligence. When X-ray lenses with radii magnify the LMXB boundary layer, it brightens by a factor of several thousand for a fraction of a second. In addition, there should be occultation events where the neutron star is blocked out. Passive X-ray lenses could require little internal power, and the LMXB light source itself shines for millions of years, with potential for an effective beacon for interstellar communication. A very large number of lenses would be needed to ensure frequent signals in all directions, however, and gathering material to construct them could be very difficult. Avoiding collisions between lenses, aiming them, and building and maintaining their precise shapes pose additional challenges. “Lens flares” of bright LMXBs are easily detectable in the Galaxy, although they would be rare events, occurring perhaps once per decade. Our more sensitive X-ray instruments could detect the eclipses of Galactic LMXBs and possibly intergalactic flares, but it is unlikely they would be observing the LMXB at the right time.

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Spreading the net

Cited by 3 publications

References 8 publications

Pulsar positioning system: a quest for evidence of extraterrestrial engineering

Pulsar positioning system: a quest for evidence of extraterrestrial engineering

Lens Flare: Magnified X-Ray Binaries as Passive Beacons in SETI

Lens Flare: Magnified X-Ray Binaries as Passive Beacons in SETI

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