Laser Communication With Proxima And Alpha Centauri Using The Solar Gravitational Lens

A sketch of the geometry. Top: The probe is at left, the Sun and Earth in the middle, and Alpha Centauri AB at right (not to scale). Advanced civilizations might place a probe 550 AU to the left of the Sun to utilize its gravitational field as a lens to amplify communication with Alpha Centauri (at right). Communication can go in both directions. Telescopes on Earth may eavesdrop on that communication beam (blue), or may receive a separate laser beam (green) from the probe. Bottom: A closeup of the beams near the Sun and Earth. As the beam widths are unknown, the blue and green beams may overlap if extraterrestrial probes emit suboptimal beam widths for technical trade-offs we can’t anticipate.

A search was conducted for laser signals, both sub-second pulses and continuous emission, from the regions of the sky opposite Proxima and Alpha Centauri.

These regions are located at the foci of the gravitational lensing caused by the Sun, ideal for amplifying transmissions between our Solar System and those two nearest stellar neighbors. During six months in 2020 and 2021, 88000 exposures for Proxima Cen and 47000 exposures for Alpha Cen were obtained.

No evidence was detected of light pulses or continuous laser emission in the wavelength range of 380 to 950 nm. We would have detected a laser having a power of just 100 Watts.

Geoffrey W. Marcy, Nathaniel K. Tellis, Edward H. Wishnow
Comments: 26 pages, 12 figures
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2110.10247 [astro-ph.IM] (or arXiv:2110.10247v1 [astro-ph.IM] for this version)
Submission history
From: Geoffrey W. Marcy
[v1] Tue, 19 Oct 2021 20:33:02 UTC (10,143 KB)

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