Looking for lurkers —a new way to do SETI

earth moon
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The most recently discovered group of rocky bodies nearby Earth are termed co-orbital objects. These may have been an attractive location for extraterrestrial intelligence (ETI) to locate a probe to observe Earth throughout our deep past. Co-orbital objects approach Earth very closely every year at distances much shorter than anything except the moon. They have the same orbital period as Earth. These near-Earth objects provide an ideal way to watch our world from a secure natural object. Co-orbitals provide resources an ETI might need: materials, constant solar energy, a firm anchor, concealment.

Co-orbitals have been little studied by astronomy and not at all by SETI or planetary radar observations. James Benford has proposed both passive and active observations of them as possible sites for ET probes that may be quite ancient.

A "Lurker' is a hidden, unknown and unnoticed observing probe. They may respond to an intentional signal and may not, depending on unknown alien motivations. Lurkers would likely be robotic, like our own Voyager and New Horizons probes.

Long-lived robotic lurkers could have been sent to observe Earth long ago. As they would remain there after their energy supply runs out, this is extraterrestrial archeology. If we find nothing there, this gives us a profound result: no one has come to look at the life of Earth, which has been evident in our atmosphere's spectral lines over interstellar distances for over a billion years.

Co-orbitals are attractive targets for SETI searches because of their proximity. Benford thinks we should move forthrightly toward observing them, both in the electromagnetic spectrum of microwaves and light, and planetary radar. And we can visit them with probes. The most attractive target is "Earth's Constant Companion' 2016 HO3, the smallest, closest, and most stable (known) quasi-satellite of Earth. Getting there from Earth orbit requires little rocket propulsion and can be done in short trips. China has announced they are going to send a to 2016 HO3.

The well-regarded astronomy journal of record, Astrophysical Journal, is publishing Benford's paper "Looking for Lurkers: Co-orbiters as SETI Observables" in the near future.

This is the latest in an agenda Benford has carried out in imaginative searches for interstellar communication. His first work with other yielded the term "Benford Beacons'—short microwave bursts to attract attention, like lighthouses. Later he pointed out the uses of powerful electromagnetic beams to send light spacecraft, "sails," in interplanetary exploration. His Lurkers proposal moves on to actual relic alien spacecraft that may have been nearby for longer than humans have existed.

Interstellar travel is challenging—no craft engineered by humans has yet traveled further than the outskirts of our own Solar System. One project working to change that is Breakthrough Starshot, which aims to send a gram-sized spacecraft to a nearby star system at around 20 percent of the speed of light. "Within the next few decades we hope humanity will become an interstellar species," remarked Breakthrough Initiatives Chairman Dr. Pete Worden. "If intelligence arose elsewhere in our galaxy, it may well have sent out similar probes. It's intriguing to think that some of these may already have reached our own Solar System."

The paper is titled "Looking for Lurkers: Objects Co-orbital with Earth as SETI Observables," soon to be published by the Astrophysical Journal.

Explore further

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More information: James Benford. Looking for Lurkers: Co-orbiters as SETI Observables, The Astronomical Journal (2019). DOI: 10.3847/1538-3881/ab3e35

Looking for Lurkers James Benford arXiv:1903.09582v2 [astro-ph.IM]: arxiv.org/abs/1906.03696

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Citation: Looking for lurkers —a new way to do SETI (2019, September 23) retrieved 22 October 2019 from https://phys.org/news/2019-09-lurkers-seti.html
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Sep 23, 2019
Any interstellar probes are likely to be very high order AI - probably beyond human. They may well include self repair and self replicating abilities.
Also, the best place to observe the Earth over millions of years are the lunar polar regions. More specifically, the Luna South Pole with its known cavern systems.

Sep 23, 2019
Meanwhile, at a top secret location on the Moon, aptly designated, Lizard People High Command, nostrils are flaring and digits are pointing as answers are demanded, for how this shocking tidbit eluded their suppression protocols.

Sep 23, 2019
Not sure about this because IF ET is out there, somewhere, it's unlikely to be in our SS and so we have the travel time problem. If ET was capable of sending probes at high or, to us, fictitious v then any ET driven craft would truly amazing. Therefore surely that would make probes redundant, wouldn't it? Or if these probes were sent long long ago then ET would probably have overtaken them by now. And IF ET is already here why the need for probes? In any case wouldn't 'alien archaeology' investigations be best suited for when we are able to travel through the SS? No, I think here is a more reason to use our resources for fact finding about the SS and the universe...and IF ET is watching well, we'll be putting on a good show eh? Ha! But then I'm thinking like a Human and maybe ET doesn't

Sep 23, 2019
"lurkers"? really?
okay my turn to monger some woo
the most likely lurkers to be found in orbit in Earth/Luna space will be defunctional spy satellites

which ever acronymic agency had spent lavish quantities from the Black Budget on developing & launching their version of a Tesla?
will not be at all amused
to have their futile fatuity exposed to public scrutiny

but the discovery will result in the usual clickbait headlines cherished by unimaginative editors


for years too come all our looneyticks will be insisting the headlines have to be true!
for proof they will offer that alien crafts designated as "Marie Calendar's Pies"?
are actually a code that the fakirs will explain endlessly,
as "Marie Calendar Spies"

the nutcases will be making the pie shop employees nervous as our less than favorite looms "lurk" around the shop, peering in the windows

Sep 24, 2019
Of course it's possible as humanity reaches peak lunacy ET just can't stop laughing

Sep 25, 2019
The idea of extra-terrestrial intelligence is as good as an imagination of sci-fi fiction or astrology. This is pure pseudoscience lacking evidence of intelligent aliens, UFOs, etc.

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