Are the aliens already on planet Earth

The story: The project SETI is a modern astronomical endeavour, dating to 1959 (first paper) and 1960 (first observation). Modern UFO sightings date t

Are the aliens already on planet Earth

---

• The story: The project SETI is a modern astronomical endeavour, dating to 1959 (first paper) and 1960 (first observation). Modern UFO sightings date to the late 1940s. SETI usually requires a graduate degree in astronomy, and its scientists disdain UFOers for requiring nothing more than a camera that takes blurry photos! Both are trying to find Extraterrestial Life (ET).
• What happens: The SETI observes stars for artificial signals, a communication strategy that has severe drawbacks from ET’s point of view. In order for it to succeed, ET would have to target each of potentially millions of promising nearby stars (including humans') continuously, and do so over potentially billions of years. It would need also to maintain a dedicated receiver for each target star to be certain not to miss a return message if and when it arrives. The cost of this strategy in time, energy and materials would be immeasurable. And then there's the question of language being used to communicate.
• Robotic probes: This led some experts to think that aliens would be better served by sending robotic probes. Relatively simple flyby probes might intermittently surveil nascent solar systems, for example, at 200-million-year intervals. Star systems with biogenic planets might be surveilled more often. Highly capable probes might be placed permanently in the vicinity of planets that have achieved multicellularity as indicated by their oxygen-rich atmospheres or other biosignatures. Once a permanently placed probe had detected artificial electromagnetic leakage, indicating that one multicellular species had become technologically intelligent, it would attempt to decode the species.
1. The local probe might need to send data back to its home base for deeper analysis and/or instructions on how to proceed.
2. If the probe began transmitting data to its home in 1950 after its detection of early television signals, and if that home base were located at the modest distance of 150 light-years, then the earliest year in which the probe might receive instructions to make contact with Earth would be 2250.
3. The ensuing dialogue will take place in near real time, as opposed to the painfully slow dialogue between ourselves and an alien civilization transmitting from a star at hundreds or thousands of light years distance. An alien probe need not reveal the location of its home base, obviating any danger to the progenitor civilization. A fully autonomous probe would be able to communicate with humans even if its progenitor civilization is long extinct.
• Smarter way to communicate: Provided that a probe does belong to an existing civilization or network of civilizations, there remains the problem of how it might communicate with them. To do so directly would require an enormous transmitter. A better solution would be to string communication nodes at close proximity to one another, perhaps one in orbit around every star, and perhaps located at a sufficient distance from the star to enable the use of it as a gravity lens, per Einstein’s theory of general relativity. For the sun, that focal point begins at 550 Earth-sun distances (AU) at which point the node would achieve signal gain of approximately a billion.  
1. Large numbers of ET civilization might contribute to this nodal system, and the store of information would only grow with time regardless of whether the contributing civilizations persist or have gone extinct.
2. Humans might contribute Aristotle, Shakespeare, etc. to this Encyclopedia Galactica. ET may wish to recruit humans into the galactic club so that we might manufacture probes and nodes, and otherwise take responsibility for the maintenance of the interstellar communication system within our immediate stellar neighborhood. That would be our bargaining chip.
• Limitations of SETI: SETI's stellar observations presume a very faint signal that would require Earth’s most powerful telescopes to detect. However, highly sensitive telescopes have very small fields of view. Detecting a local robotic probe requires the opposite strategy. Because of a probe’s close proximity to Earth, its signal would be much brighter than an interstellar beacon. So SETI’s best strategy would be to sacrifice great sensitivity in favour of a wide a field of view or, better yet, all-sky-all-the-time observing. Such systems are being built now or planned.
• Summary: So are we now expecting some of those UFO picture to be real glimpses of such probes? Who knows.

 

Join PT courses | PT Youtube | PT App | Contribute |  Testimonials