Breakthrough Listen frigiver 2 petabyte data fra SETI-undersøgelsen af ​​Mælkevejen

Breakthrough Listen Initiative frigav i dag data fra den hidtil mest omfattende undersøgelse af radioemissioner fra Mælkevejsgalaksens fly og regionen omkring dets centrale sorte hul, og det inviterer offentligheden til at søge i dataene efter signaler fra intelligente civilisationer.

Ved en mediebriefing i dag i Seattle som en del af det årlige møde i American Association for the Advancement of Science (AAAS), Gennembrud Lyt-hovedforsker Andrew Siemion fra University of California, Berkeley, annoncerede udgivelsen af ​​næsten 2 petabyte data, det andet datadump fra den fire år gamle eftersøgning af udenjordisk intelligens (SETI). En petabyte af radio- og optiske teleskopdata blev frigivet i juni sidste år, den største udgivelse af SETI-data i feltets historie.

Dataene, det meste af det frisk fra teleskopet forud for detaljeret undersøgelse fra astronomer, kommer fra en undersøgelse af radiospektret mellem 1 og 12 gigahertz (GHz). Omkring halvdelen af ​​dataene kommer via Parkes radioteleskop i New South Wales, Australien, hvilken, på grund af dens beliggenhed på den sydlige halvkugle, er perfekt placeret og instrumenteret til at scanne hele den galaktiske skive og det galaktiske center. Teleskopet er en del af Australia Telescope National Facility, ejet og administreret af landets nationale videnskabsagentur, CSIRO.

Resten af ​​dataene blev registreret af Green Bank Observatory i West Virginia, verdens største styrbare radioparabol, og et optisk teleskop kaldet Automated Planet Finder, bygget og drevet af UC Berkeley og placeret ved Lick Observatory uden for San Jose, Californien.

"Siden Breakthrough Listens første dataudgivelse sidste år, vi har fordoblet, hvad der er tilgængeligt for offentligheden, " sagde Breakthrough Listens ledende systemadministrator, Matt Lebofsky. "Det er vores håb, at disse datasæt vil afsløre noget nyt og interessant, det være sig andet intelligent liv i universet eller et endnu uopdaget naturligt astronomisk fænomen."

National Radio Astronomy Observatory (NRAO) og det privatfinansierede SETI Institute i Mountain View, Californien, annoncerede også i dag en aftale om at samarbejde om nye systemer for at tilføje SETI-funktioner til radioteleskoper, der drives af NRAO. Det første projekt vil udvikle et system til piggyback på National Science Foundations Karl G. Jansky Very Large Array (VLA) i New Mexico og levere data til avanceret digitalt backend-udstyr bygget af SETI Institute.

"SETI Institute vil udvikle og installere en grænseflade på VLA, tillader hidtil uset adgang til den rige datastrøm, der kontinuerligt produceres af teleskopet, mens det scanner himlen, " sagde Siemion, WHO, ud over sin stilling i UC Berkeley, er Bernard M. Oliver Chair for SETI ved SETI Institute. "Denne grænseflade vil give os mulighed for at udføre en kraftfuld, bredområde SETI-undersøgelse, der vil være langt mere komplet end nogen tidligere sådan søgning."

"Da VLA udfører sine sædvanlige videnskabelige observationer, dette nye system vil give mulighed for en yderligere og vigtig brug af de data, vi allerede indsamler, " sagde NRAO-direktør Tony Beasley. "At afgøre, om vi er alene i universet som teknologisk dygtigt liv, er blandt de mest overbevisende spørgsmål i videnskaben, og NRAO-teleskoper kan spille en stor rolle i at besvare det."

"For hele menneskehedens historie, vi havde en begrænset mængde data til at søge efter liv hinsides Jorden. Så, alt vi kunne gøre var at spekulere. Nu, da vi får en masse data, vi kan lave rigtig videnskab og, med at gøre disse data tilgængelige for offentligheden, så kan enhver, der ønsker at vide svaret på dette dybe spørgsmål, " sagde Yuri Milner, grundlæggeren af ​​Breakthrough Listen.

Earth transit zone undersøgelse

Ved at frigive de nye radio- og optiske data, Siemion fremhævede en ny analyse af en lille delmængde af dataene:radioemissioner fra 20 nærliggende stjerner, der er justeret med jordens kredsløbsplan, således at en avanceret civilisation omkring disse stjerner kunne se Jorden passere foran solen (en "transit" som dem, der fokuseres på af NASAs Kepler-rumteleskop). Udført af Green Bank Telescope, jordovergangszoneundersøgelsen observeret i radiofrekvensområdet mellem 4 og 8 gigahertz, det såkaldte C-bånd. Dataene blev derefter analyseret af den tidligere UC Berkeley bachelor Sofia Sheikh, nu kandidatstuderende ved Pennsylvania State University, som ledte efter lyse emissioner ved en enkelt radiobølgelængde eller et smalt bånd omkring en enkelt bølgelængde. Hun har indsendt papiret til Astrophysical Journal.

"Dette er en unik geometri, " sagde Sheikh. "Det er sådan, vi opdagede andre exoplaneter, så det giver mening at ekstrapolere og sige, at det måske er sådan, andre intelligente arter finder planeter, såvel. Denne region er blevet talt om før, men der har aldrig været en målrettet eftersøgning af den del af himlen."

Mens Sheikh og hendes team ikke fandt nogen teknosignaturer af civilisationen, the analysis and other detailed studies the Breakthrough Listen group has conducted are gradually putting limits on the location and capabilities of advanced civilizations that may exist in our galaxy.

"We didn't find any aliens, but we are setting very rigorous limits on the presence of a technologically capable species, with data for the first time in the part of the radio spectrum between 4 and 8 gigahertz, " Siemion said. "These results put another rung on the ladder for the next person who comes along and wants to improve on the experiment."

Sheikh noted that her mentor, Jason Wright at Penn State, estimated that if the world's oceans represented every place and wavelength we could search for intelligent signals, we have, til dato, explored only a hot tub's worth of it.

"My search was sensitive enough to see a transmitter basically the same as the strongest transmitters we have on Earth, because I looked at nearby targets on purpose, " Sheikh said. "So, we know that there isn't anything as strong as our Arecibo telescope beaming something at us. Even though this is a very small project, we are starting to get at new frequencies and new areas of the sky."

Beacons in the galactic center?

The so-far unanalyzed observations from the galactic disk and galactic center survey were a priority for Breakthrough Listen because of the higher likelihood of observing an artificial signal from that region of dense stars. If artificial transmitters are not common in the galaxy, then searching for a strong transmitter among the billions of stars in the disk of our galaxy is the best strategy, Simeon said.

På den anden side, putting a powerful, intergalactic transmitter in the core of our galaxy, perhaps powered by the 4 million-solar-mass black hole there, might not be beyond the capabilities of a very advanced civilization. Galactic centers may be so-called Schelling points:likely places for civilizations to meet up or place beacons, given that they cannot communicate among themselves to agree on a location.

"The galactic center is the subject of a very specific and concerted campaign with all of our facilities because we are in unanimous agreement that that region is the most interesting part of the Milky Way galaxy, " Siemion said. "If an advanced civilization anywhere in the Milky Way wanted to put a beacon somewhere, getting back to the Schelling point idea, the galactic center would be a good place to do it. It is extraordinarily energetic, so one could imagine that if an advanced civilization wanted to harness a lot of energy, they might somehow use the supermassive black hole that is at the center of the Milky Way galaxy."

Visit from an interstellar comet

Breakthrough Listen also released observations of the interstellar comet 2I/Borisov, which had a close encounter with the sun in December and is now on its way out of the solar system. The group had earlier scanned the interstellar rock 'Oumuamua, which passed through the center of our solar system in 2017. Neither exhibited technosignatures.

"If interstellar travel is possible, which we don't know, and if other civilizations are out there, which we don't know, and if they are motivated to build an interstellar probe, then some fraction greater than zero of the objects that are out there are artificial interstellar devices, " said Steve Croft, a research astronomer with the Berkeley SETI Research Center and Breakthrough Listen. "Just as we do with our measurements of transmitters on extrasolar planets, we want to put a limit on what that number is."

Regardless of the kind of SETI search, Siemion said, Breakthrough Listen looks for electromagnetic radiation that is consistent with a signal that we know technology produces, or some anticipated signal that technology could produce, and inconsistent with the background noise from natural astrophysical events. This also requires eliminating signals from cellphones, satellitter, GPS, internet, Wi-fi and myriad other human sources.

In Sheikh's case, she turned the Green Bank telescope on each star for five minutes, pointed away for another five minutes and repeated that twice more. She then threw out any signal that didn't disappear when the telescope pointed away from the star. Ultimativt, she whittled an initial 1 million radio spikes down to a couple hundred, which she was able to eliminate as Earth-based human interference. The last four unexplained signals turned out to be from passing satellites.

Siemion emphasized that the Breakthrough Listen team intends to analyze all the data released to date and to do it systematically and often.

"Of all the observations we have done, probably 20% or 30% have been included in a data analysis paper, " Siemion said. "Our goal is not just to analyze it 100%, but 1000% or 2000%. We want to analyze it iteratively."