Is there any­body out there?

DAVID HAMBLING won­ders if geeky math­e­mat­i­cal mes­sages are go­ing to get the aliens’ at­ten­tion

Fortean Times - - Science -

Sci­en­tists have been scan­ning the heav­ens for alien ra­dio sig­nals for decades [ FT346:16], but the Search for Ex­tra-Ter­res­trial In­tel­li­gence (SETI; see FT157:42-46) has only yielded one tan­ta­lis­ing hit, and that was 40 years ago. More re­cently there has been grow­ing ex­cite­ment around whether the dim­ming of a stel­lar ob­ject known as Tabby’s Star in­di­cates alien ac­tiv­ity [ FT348:14]. In the last few months sci­en­tists have gained some sur­pris­ing new in­sights re­lat­ing to both of these, and to the quest for alien life in gen­eral.

In Au­gust 1977, the Ohio State Univer­sity’s SETI pro­gram picked up a pow­er­ful sig­nal at 1,420 MHz, the hy­dro­gen band where alien com­mu­ni­ca­tion seemed most likely. As­tronomer Jerry Eh­man wrote “Wow!” on the print­out, and the ra­dio tele­scope was swiftly pointed at the area of the sky where the sig­nal had orig­i­nated, but noth­ing else was ever re­ceived.

Re­searchers from the Cen­tre of Plan­e­tary Sci­ence now claim that a comet may have been the source. Comets carry a hy­dro­gen cloud that might emit ra­di­a­tion on the hy­dro­gen fre­quency, and two comets, both undis­cov­ered at the time, were pass­ing through the area be­ing scanned. Astro­nom­i­cal ob­ser­va­tions early this year con­firmed comets can emit on ex­actly the right fre­quency, and they are a mov­ing point source, so if a ra­dio tele­scope is even one de­gree out it will see noth­ing. The mov­ing comet will show up as a brief, elu­sive, in­tense sig­nal. This now looks like the best ex­pla­na­tion for the “Wow!” sig­nal.

Mean­while there has also been fur­ther study of Tabby’s Star. This had showed a pat­tern of dim­ming that doesn’t fit with nor­mal astro­nom­i­cal ob­jects (such as comets and as­ter­oids) pass­ing in front of the star. Some sug­gested that the shad­ows were cast by colos­sal alien build­ing work – a megas­truc­ture en­com­pass­ing Tabby’s so­lar sys­tem.

Fer­nando Balles­teros and col­leagues at the Univer­sity of Valencia in Spain have re­cently sug­gested an al­ter­na­tive so­lu­tion, although it may seem just as far-fetched. Their the­ory is that the ini­tial dim­ming in 2011 was the re­sult of a huge ringed planet, like a gi­ant alien ver­sion of Saturn, par­tially eclips­ing Tabby’s Star. The tilt of the rings might pro­duce the sort of asym­met­ric dim­ming which was ob­served. Af­ter that, the 2013 dim­ming may have been caused by a vast swarm of as­ter­oids trail­ing in the gi­ant planet’s wake, just as Jupiter pulls the Tro­jan as­ter­oids af­ter it in our So­lar Sys­tem.

Fi­nally, the lat­est, com­par­a­tively mi­nor dim­ming event might have been caused by the ringed planet pass­ing be­hind Tabby’s Star. When this hap­pens, light re­flected from the planet is in­vis­i­ble to us, and the over­all bright­ness of the star sys­tem is re­duced.

Balles­teros’s model does not re­quire any bend­ing of laws of physics. Fur­ther­more, it pre­dicts there will be an­other dim­ming event in 2021 as the alien Saturn swings around again. Testable pre­dic­tions are one of the hall­marks of good sci­ence. If these lat­est the­o­ries are cor­rect, then SETI seems to be get­ting nowhere and there are no traces of aliens out there. As physi­cist En­rico Fermi fa­mously asked in the 1940s: “Where is ev­ery­body?” One pos­si­bil­ity is that there are no aliens, at least not tech­no­log­i­cally ad­vanced ones who wish to com­mu­ni­cate. The chances of life de­vel­op­ing, or in­tel­li­gence evolv­ing from life, may be much less than sci­en­tists as­sume.

An­other sug­ges­tion is that we are sim­ply lis­ten­ing to the wrong thing. Ra­dio broad­casts on the hy­dro­gen fre­quency might seem ob­vi­ous to us, but as the re­cent comet dis­cov­ery re­vealed, such sig­nals may have more than one cause. Aliens might pre­fer to com­mu­ni­cate via neu­tri­nos, a tech­nol­ogy which we have yet to mas­ter, or via what sci­en­tists term “Zeta rays” – forms of ra­di­a­tion that we do not even sus­pect. If this is the case, then it is just a mat­ter of a few hun­dred or thou­sand years be­fore we de­velop suit­able tech­nol­ogy and then we will be able to tune in.

How­ever, the prob­lem may not be one of tech­nol­ogy. In a re­cent ex­er­cise René Heller of the Max Planck In­sti­tute cre­ated an im­i­ta­tion alien mes­sage of some two mil­lion dig­its. It in­cluded within it the first sev­eral hun­dred prime num­bers, which were im­por­tant to de­cod­ing the rest of the mes­sage: a selfie of an imag­i­nary alien and some FAQ on their size, life­span and the lo­ca­tion of their home­world.

Heller re­ceived over 300 re­sponses to this SETI De­crypt chal­lenge, with 66 giv­ing com­pletely cor­rect answers to the six ques­tions he posed about the mes­sage con­tents. Heller’s mes­sage con­tains in­for­ma­tion that SETI geeks might find in­ter­est­ing, but is not rep­re­sen­ta­tive of mes­sages sent by any other com­mu­nity on Earth.

SETI ap­pears to be look­ing for mes­sages from peo­ple ex­actly like those who set up SETI on Earth, a small es­sen­tially white, male mid­dle­class sci­en­tific sub­cul­ture. To many peo­ple mu­sic or art may seem more uni­ver­sal forms of com­mu­ni­ca­tion than math­e­mat­ics. There is an as­sump­tion that aliens would have de­vel­oped their tech­nol­ogy through a sim­i­lar route to us, and would nec­es­sar­ily have come across the same sort of math­e­mat­ics along the way. This may not be the case.

Also, a sig­nal may not be sent out for the ben­e­fit of the re­cip­i­ents. To the peo­ple who paid for the Apollo pro­gram, the sci­en­tific achieve­ment was ir­rel­e­vant: what mat­tered was putting an Amer­i­can flag on the Moon. Beam­ing out the na­tional an­them to claim alien civil­i­sa­tions may be more im­por­tant than mak­ing the mes­sage in­tel­li­gi­ble, and it is hard to see Don­ald Trump or Vladimir Putin fund­ing an alien con­tact ef­fort un­less there was an ad­van­tage to be gained.

We may not have heard from aliens be­cause they are too dif­fer­ent from us and com­mu­ni­cate in dif­fer­ent ways. But it may also be be­cause they are just like us. Aliens may not be send­ing out sig­nals be­cause there is sim­ply not enough profit to be had out of longdis­tance mes­sag­ing which, af­ter many decades, is only likely to get a re­ply from a col­lec­tion of alien geeks with an ob­ses­sive in­ter­est in prime num­bers.

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