ET discovered?

[Ian Thomas]

This one's looking like a serious contender .. but it's early days.

The G Search for Extraterrestrial Civilizations with Large Energy Supplies. IV. The Signatures and Information Content of Transiting Megastructures
Jason T. Wright, Kimberly M. S. Cartier, Ming Zhao, Daniel Jontof-Hutter, Eric B. Ford
(Submitted on 15 Oct 2015)
arxiv.org/abs/1510.04606
Boyajian et al. 2015 recently announced KIC 8462852, an object with a bizarre light curve consistent with a "swarm" of megastructures. We suggest this is an outstanding SETI target.

[Isengard]

Seems fascinating, but how would you go about proving such a thing?

[dennisw]

NASA have started directing telescopic arrays to the region in the hope of discovering something, the star is 1,480 light years away (NASA round it off to 1,500) so anything we find may no longer exist. The distance is too great for us to reach it with current technology we can only hope that faster than light travel will one day be possible.

www.space.com/30855-alien-life-search-kepler-megastructure.html

[Ian Thomas]

It'd be a safe bet radio 'scopes are already listening in to that star. However it's likely no 'interesting' signals have been detected - the news would be all over the web otherwise.
If the occultations are really due to a gigantic alien construction project, the work must have been going on for centuries or millennia. Radio noise would have been noticed well before now.

[dennisw]

IMHO radio is probably not the communication of choice in highly advanced civilisations, quantum entanglement can be far more effective. It would be instantaneous, direct and untraceable.

[Ian Thomas]

A counter argument i've heard is that yes even if entanglement or neutrinos or whatever can be used for comms, advanced ETs would still keep using EM waves for simple 'day to day' purposes, alongside quantum systems. Same as we still use light and sound for basic communications: lighthouses for ships at sea, PA systems and sirens simply because these are convenient. A stone age tribesman living near a coast could not detect us using the internet but he would sure see lights on a passing ship and hear noises coming from if it cruised in close. Ditto aliens. Forget beacons, look for their works and spillover noise.

[Ian Thomas]

All quiet so far

Radio SETI Observations of the Anomalous Star KIC 8462852
5 Nov 2015
arxiv.org/abs/1511.01606
No narrowband radio signals were found at a level of 180-300 Jy in a 1 Hz channel, or wideband signals above 100 Jy in a 100 kHz channel.

[dennisw]

The star is almost 1,500 light years from Earth so we are assuming intelligent life using radio about the time the Roman Empire was collapsing and before the birth of Muhammad?

[youcantry]

Oct 23, 2015 7:37:46 GMT 10 Ian Thomas said:

It'd be a safe bet radio 'scopes are already listening in to that star. However it's likely no 'interesting' signals have been detected - the news would be all over the web otherwise.
If the occultations are really due to a gigantic alien construction project, the work must have been going on for centuries or millennia. Radio noise would have been noticed well before now.

Isn't that a bit like saying "if there really is a gold nugget amongst all those grains of sand in the river bed, it would have been lying there for centuries or millenia. We would have noticed it well before now"?

[Ian Thomas]

Nov 16, 2015 12:02:55 GMT 10 youcantry said:

Oct 23, 2015 7:37:46 GMT 10 Ian Thomas said:

 ...   Radio noise would have been noticed well before now.

Isn't that a bit like saying "if there really is a gold nugget amongst all those grains of sand in the river bed, it would have been lying there for centuries or millenia. We would have noticed it well before now"?

There's been a LOT of listening for alien radio signals over the last 6 decades. I think we can be reasonably sure there are no powerful transmitters operating in any nearby star system. That's a might small sample out of the entire galaxy but it might well mean technological civilisations are not common. If advanced alien civilisations were everywhere like they're portrayed in Star Wars etc then there should be a few close by.

[Ian Thomas]

Here's a seriously dire thought. What if the first alien civilisation we may have come across turns out to be a long dead one?

"If the cause of the KIC 8462852 light curve of is not natural than the best answer that fits all constraints may be a serendipitous discovery of a failed early Type II or border Type I/Type II extraterrestrial civilization."
cosmology.com/Commentary6KIC8462852.html

The implication of this dude's suggestion is the weird dips in the star's light could be caused by the remains of a Dyson sphere that broke up eons ago ...

[Ian Thomas]

Don't appear to be any optical, as in high-power laser signals coming from the system. In other words, nuthin' so far ..

Optical SETI Observations of the Anomalous Star KIC 8462852
8 Dec 2015
arxiv.org/abs/1512.02388
To explore the hypothesis that KIC 8462852's aperiodic dimming is caused by artificial megastructures in orbit ... we searched for electromagnetic signals from KIC 8462852 indicative of extraterrestrial intelligence. The primary observations were in the visible optical regime ...

[Isengard]

I wonder what the odds are that life literally only occurred as an incredible one in a trillion freak occurrence on Earth?

[Ian Thomas]

Dec 20, 2015 3:49:33 GMT 10 Isengard said:

I wonder what the odds are that life literally only occurred as an incredible one in a trillion freak occurrence on Earth?

Seems inconceivable - but that's the way things are looking the more we find out. :/

[dennisw]

The creationists would be saying "what did you expect" God made it all in six days why would he bother going through all that again. Logic says it is totally improbable and ancient Jewish texts speak of "seven inhabited worlds" and Kabbalah describes these worlds which were explained to ancient mystics by "messengers from Heaven".

[Isengard]

Why do we assume aliens will use the same technology as us? I'm sure there are many means of communication that could be used that we haven't thought of, wouldn't recognise, etc.

[dennisw]

We are on the verge of developing quantum communication, Birmingham University claim their system will be on the market within two years. The system uses quantum entangled crystals so uses no radio waves is instantaneous has unlimited range and only the entangled crystals respond to the communication.

[Isengard]

Instantaneous? Even over interstellar distances?? Sounds like it'll be even easier for the missus to nag me to come back from the pub...

[dennisw]

Dec 23, 2015 20:18:01 GMT 10 Isengard said:

Instantaneous? Even over interstellar distances?? Sounds like it'll be even easier for the missus to nag me to come back from the pub...

Don't buy her a quantum phone, there would be no black spots and no loss of signal; but then even a quantum phone will have an off switch and a battery that might go flat. There is always time for another beer.

[vincent]

Seems to me that I heard / read someplace not too long ago that any sort of current-tech radio transmission would diminish in strength so much by about forty light years out that it would be weaker than normal electromagnetic noise, so it would be undetectable.

[Ian Thomas]

If there really are advanced ETs out there, signal attenuation might be a good thing.
Bad aliens was the theme in Across the Sea of Suns ..

en.wikipedia.org/wiki/Across_the_Sea_of_Suns

[Ian Thomas]

This star just got weirder still. Occultations by dust were ruled out previously on account of its low IR signature. Now comet occultations are shown to be highly implausible.
So ... what's left?

KIC 8462852 Faded at an Average Rate of 0.165+-0.013 Magnitudes Per Century From 1890 To 1989
Bradley E. Schaefer, arXiv:1601.03256 [astro-ph.SR]
arxiv.org/abs/1601.03256

This century-long dimming is completely unprecedented for any F-type main sequence star. So the Harvard light curve provides the first confirmation (past the several dips seen in the Kepler light curve alone) that KIC 8462852 has anything unusual going on. The century-long dimming and the day-long dips are both just extreme ends of a spectrum of timescales for unique dimming events, so by Ockham's Razor, all this is produced by one physical mechanism. This one mechanism does not appear as any isolated catastrophic event in the last century, but rather must be some ongoing process with continuous effects. Within the context of dust-occultation models, the century-long dimming trend requires 10^4 to 10^7 times as much dust as for the one deepest Kepler dip. Within the context of the comet-family idea, the century-long dimming trend requires an estimated 648,000 giant comets (each with 200 km diameter) all orchestrated to pass in front of the star within the last century.

[Isengard]

In all honesty this explanation means nothing to me! Physics and astronomy are not my strong suits...

[dennisw]

In the life of a star 100 years is such a tiny fraction that we really shouldn't assume too much, I worked on a concept some time back that examined the correlation between cosmic microwave radiation and solar cycles. The theory is that our own sun has an 11-12 year fluctuation because at its highest the solar wind blocks CMR causing the sun to "go quiet" as the solar wind decreases CMR increases causing the solar activity to become excited and swing back toward higher activity. There is no reason that this type of oscillation could not occur on grander scales in other regions of space and could at least theoretically cause or contribute to observed anomalies.

[Ian Thomas]

Jan 17, 2016 8:30:23 GMT 10 Isengard said:

In all honesty this explanation means nothing to me! Physics and astronomy are not my strong suits...

They're looking for explanations which do not involve the "A" word. viz Artificial. viz Aliens. That's fine, that's wotsisname's razor.

Whatever's causing the dimming has to be gigantic but also must be low density coz it's more or less about Jupiter's distance from our sun. But the dimming is irregular so what ever the object is (objects are) it (they) must have an irregular structure. ie It's not a giant planet.

A dust disc was ruled out because there's no infrared trace of dust in the system. It's a youngish star, an F-type, these are brighetr than Sol, a G type star, and they tend not have dust discs anyway. An alien civilsiation is not expected for F-type starstr because it's thought there would not be enough evolution-time for one to arise.

Next idea was a swarm of giant comets that clumped together somehow to block the star's light. But this recent paper shows that's not plausible - needs too many comets. Besides, it's been going on for at least 100 years.

Yeah, it might be ET imho. Can't rule it out at this stage.

[Ian Thomas]

Somethin' weird in the neighbourhood ..

Study Confirms That Something's Weird About The 'Alien Megastructure' Star
Sarah Fecht, Jan 20 2016
www.popsci.com.au/space/study-confirms-that-somethings-weird-about-the-alien-megastructure-star,413846

[Ian Thomas]

Long term dimming-trend or not? Yes it is, not it's not. Is it aliens, or not?
Star wars commencing ...

KIC 8462852 did likely not fade during the last 100 years
Michael Hippke, Daniel Angerhausen, 27 Jan 2016

A recent analysis found a "completely unprecedented" dimming of 0.165±0.013 magnitudes per century in the F3 main sequence star KIC8462852. This star is interesting, as it shows episodes of day-long dips with up to 20% dimming of unknown origin. We re-analyze the same Harvard archival Johnson B photometry and find comparable dimmings, and structural breaks, for 18 of 28 checked F-dwards (64%) in the Kepler field of view. We conclude that the Harvard plates photometry suffers from imperfect long-term (1890--1989) calibration. The most likely explanation for the century-long dimming of KIC8462852 is thus a data artefact, and it is probably not of astrophysical origin.
arxiv.org/abs/1601.07314

[Ian Thomas]

Search for optical signals in archived data. No joy.

A Search for Brief Optical Flashes Associated with the SETI Target KIC 8462852
3 Feb 2016
We describe an analysis methodology for optical SETI, which we have used to analyse nine hours of serendipitous archival observations of KIC 8462852 made with the VERITAS gamma-ray observatory between 2009 and 2015. No evidence of pulsed optical beacons, above a pulse intensity at the Earth of approximately 1 photon per m^2, is found.
arxiv.org/abs/1602.00987

The idea that aliens would set up beacons is fallacious imho. It's probly not ET ... but still can't rule it out. If they're not sending out powerful radio or optical broadcasts, we'd only be able to detect them by their works. If any.

[Ian Thomas]

By their works shall we find them. Forget radio beacons and all that.

Power Beaming Leakage Radiation as a SETI Observable
Posted on February 18, 2016 by arxiver
arxiver.wordpress.com/2016/02/18/power-beaming-leakage-radiation-as-a-seti-observable-ima/

@ Astrophysics ..
arxiv.org/abs/1602.05485

[Ian Thomas]

The plot thickens about KIC 8462852. Okay, it's not a swarm of comets. Even the dust cloud idea seems artificial.
Err .. artificial?
Is probly still too soon to talk aliens ...

The real reason why the KIC 8462852 comet hypothesis is dead
By Jose Solorzano, March 5th 2016
www.science20.com/indepth_analytics/blog/the_real_reason_why_the_kic_8462852_comet_hypothesis_is_dead-167340
.. It's actually a statement we find in the concluding section of the paper:

This comet family model does not explain the large dip observed around day 800 and treats it as unrelated to the ones starting at day 1500. The flux changes too smoothly and too slowly to be easily explained with a simple comet family model.

This remarkable acknowledgment should not be understated. The dip "around day 800" (from now on, the day-792 dip) is indeed large. It can't be dismissed as an amazing coincidence.