SETI

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Red dwarf stars outnumber yellow dwarf stars like our sun by over a factor of ten. Observations of exoplanets have also shown that rocky, and potentially habitable, planets are just as common around red dwarfs as yellow dwarfs. But if these much smaller stars are more commonplace, then why do we find ourselves around a yellow star like the sun, instead of a red dwarf?

My co-authors and I attempt to address this question of selection bias in a recent paper titled “Why do we find ourselves around a yellow star instead of a red star?” and published in International Journal of Astrobiology. We take a statistical approach to thinking about the region around all stars where life is most likely to develop. The liquid water habitable zone provides the best observational constraint on where we would expect to find planets that could support conscious observers like us, and this study examines the probability of finding oneself on a planet in the habitable zone of a yellow dwarf star, compared to a red dwarf. The results show that even though red dwarfs are much more numerous, they have a narrower habitable zone than yellow dwarfs, so our existence around a star like the sun is actually to be expected.

This study also considers that red dwarf stars will be even more numerous in the distant future of the universe, due to their much longer lifetimes than other stars. If these red dwarf stars will eventually become the predominant place for conscious observers to develop, then why do we not instead find ourselves around a red dwarf star billions or trillions of years into the future? The statistics for this aspect of the problem suggest that our existence around a yellow dwarf star today, compared to a red dwarf star in the future, might be a slight statistical anomaly—perhaps on the order of finding oneself born ambidextrous or with perfect pitch. But this statistical unlikelihood might also suggest that life is wholly impossibly around red dwarf stars, or else any type of conscious observers that do develop around such stars will be drastically different from our type of conscious life.

Finding sources of funding to search for life in the universe can be tricky, with only a few individual wealthy investors and limited opportunities for government research support. New fundraising ideas are needed in order to sustain the search for extraterrestrial intelligence (SETI) over the coming decades.

In a recent paper titled “Funding the search for extraterrestrial intelligence with a lottery bond,” published in Space Policy, I propose the establishment of a “SETI Lottery Bond” to help defray the costs of operating observing facilities like the Allen Telescope Array. The SETI Lottery Bond would provide a fixed-rate of interest that continues in perpetuity, until the first confirmed discovery of extraterrestrial intelligent life, at which point a subset of shares will be awarded a prize from a lottery pool. Investors can also trade their shares, so that SETI Lottery Bond shares may be passed between generations, teaching the value of intergenerational savings while maintaining hope for the discovery of extraterrestrial life.

Lottery-based savings products can only be offered by financial institutions with the legal authorization to engage in banking and gaming activities. I propose that one or more financial institution could realize a profit through the establishment and management of a SETI Lottery Bond, while simultaneously promoting individual savings habits and assisting the search for extraterrestrial intelligent life.

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Deliberate and unintended radio transmissions from Earth propagate into space. Deliberate transmissions are intended as attempts to send messages to potential extraterrestrial watchers (known as “Messaging to Extraterrestrial Intelligence”, or METI). Unintended radio leakage includes television and radio broadcasts, cell phone networks, and high-power military and astronomical radars. This radiation gives evidence of our technological civilization to any extraterrestrial watchers.

Do radio transmissions pose a risk and should they continue? I recently published a paper with a team of BMSIS scientists in the journal Space Policy that examines the various benefits and harms that could arise as a result of human transmissions into space. In general, we think that the value of radio communication on Earth today is too large to justify ceasing all radio transmissions in order to reduce the risk of being found by a hypothetical harmful extraterrestrial civilization.

Most deliberate METI transmissions are detectable over much smaller volumes than the radio leakage. These transmissions are either short in duration or use a high bandwidth, in contrast to television carrier waves or high-power radars. These transmissions do not increase the probability of contact with extraterrestrial civilization. Such METI attempts are also valuable for education and public outreach efforts on Earth and for developing scientific groundwork for future METI projects. Given the modest costs associated with METI at low levels of detectability, we think that such projects should continue.

In contrast, high-power and persistent METI projects could have detectable volumes greater than the radio leakage, and would have a greater probability of being detected by any extraterrestrial watchers. The consequences of contact with extraterrestrials are highly uncertain, so we cannot say with confidence whether or not such attempts at METI should proceed. One additional benefit of transmitting messages into space at high power is that they serve a purpose analogous to digital time capsules, preserving the knowledge of human civilization, should our species become extinct. This may provide an additional justification for engaging in METI; however, the cost of maintaining such a long duration beacon must be weighed against the long-term benefits.

Existing governing structures or treaties are currently lacking for METI. Active engagement in long-term METI would benefit from international cooperation in order to accurately represent Earth and humanity and to better understand how to communicate effectively with an unknown observer.

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