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Hawking wirbt für Lauschangriff auf Außerirdische
Zehn Jahre, 100 Millionen Dollar und hoffentlich ein Signal von Außerirdischen: Starphysiker Stephen Hawking macht sich für eine private Initiative zur Suche nach Leben im All stark.
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Das Projekt "Breakthrough Listen" (Durchbruch Zuhören) unter Leitung renommierter Astronomen wird von dem russischen Investor Yuri Milner finanziert, der über das kommende Jahrzehnt 100 Millionen US-Dollar investieren will. "Wir glauben, dass sich das Leben auf der Erde spontan entwickelt hat", sagte Hawking am Montag in London. In einem unendlichen Universum müsse es deswegen anderes Leben geben. "Wir sind lebendig, wir sind intelligent, wir müssen es wissen."
Beteiligt an dem Projekt ist unter anderem Frank Drake, ein Pionier der Suche nach außerirdischem Leben mit modernen Mitteln, und Geoff Marcy von der Universität Berkeley, ein führender Planetenforscher. Für "Breakthrough Listen" soll das All mit zwei der größten und leistungsstärksten Teleskope der Welt unter die Lupe genommen werden, im Green-Bank-Observatorium in West Virginia und im Parkes-Observatorium in Australien.
Alle erfassten Daten und Erkenntnisse sollen öffentlich zugänglich sein, sagte Milner, der nach eigenen Angaben nach dem ersten Mann im All, Yuri Gagarin, benannt ist. An einem einzigen Tag werde "Breakthrough Listen" mehr Daten sammeln, als bisher in einem ganzen Jahr zusammen gekommen seien. "Das Ausmaß unserer Suche wird beispiellos sein."
Abgehorcht werden sollen unter anderem eine Million Sterne in der Nähe, die Milchstraße und etwa 100 nahe gelegene Galaxien, und zwar auf allen möglichen Frequenzen. Davon gebe es immerhin zehn Milliarden, erklärte Geoff Marcy. Parallel soll es einen Wettbewerb dazu geben, welche Botschaft man Außerirdischen von der Erde aus schicken sollte.
Zu den Erfolgsaussichten konnten die Wissenschaftler am Montag keine konkreten Angaben machen. "Es ist natürlich ein riesiges Wagnis", sagte der Astrophysiker Martin Rees, der früher einen Lehrstuhl in Cambridge hatte und zum Leitungsteam gehört. "Niemand zählt auf Erfolg, aber der Lohn wird so kolossal sein, wenn man erkennt, dass es anderswo Leben gibt, dass diese Investition sich sehr lohnt." Geplant sei, dass die Mitarbeiter nebenher andere Projekte verfolgen, "damit sie nicht deprimiert werden".
Stephen Hawking, der wegen einer schweren Erkrankung gelähmt ist und sich nur über einen Computer verständigen kann, wies darauf hin, dass auch Erfolglosigkeit einer solch riesigen Suchaktion ein interessantes Ergebnis wäre. "Es ist wichtig für uns, zu wissen, ob wir alleine im Dunklen sind."
Quelle: t-online
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“Breakthrough Listen”: Giant Leap for SETI
Fascination with SETI — the search for extraterrestrial intelligence — waxes and wanes in cycles. Are other technological civilizations broadcasting their existence to the stars? It's the most important question we know about our position in the cosmos and humanity's long-term future. Are we merely like ants, hopelessly outclassed by vastly older, superior species among the stars? If so, might they help, harm, or ignore us? Or are we alone, holding in our own hands the future of conscious life itself?
Yesterday, in an announcement at the Royal Society in London, a tech billionaire and a group of eminent scientists announced a great leap forward in the search to find out. Russian investor Yuri Milner announced that he will commit $100 million to the Breakthough Prize Foundation to carry out radically ambitious SETI projects for the next 10 years under the name Breakthrough Listen.
"It's just a miracle," SETI pioneer Frank Drake told the New York Times. Said Dan Werthimer, SETI researcher and originator of the SETI@home project, "This is beyond my wildest dreams."
The Breakthrough Listen team intends to use about a third of the money to buy some 20 percent of the time on the 100-meter Green Bank radio telescope in West Virginia, as well as substantial time on the 64-meter Parkes radio dish in Australia, for the next 10 years. These purchases will help ensure a future for both financially imperiled telescopes. Other radio telescopes might be added.
Another third of the funds will go toward developing powerful, sensitive, new receivers and processors to examine billions of narrow frequency channels from 1 to 10 gigahertz. This range spans most of the best radio frequencies: those that get through Earth's atmosphere and are not swamped by cosmic background noise. No protracted search has ever has ever successfully covered such a wide range of frequencies.
The radio project will use two opposite search strategies. The first is a "targeted search." We now know that most stars have planets. The telescopes will examine the nearest 1 million stars in case other civilizations are relatively common — meaning they currently inhabit more than one in a million solar systems — but none broadcasts its existence to the cosmos at terribly high power. Looking even closer, the Breakthrough Listen team claims that the project would be able to hear an ordinary air-traffic control radar aimed our way from the nearest thousand stars.
On the other hand, many who have studied SETI search strategies conclude that the most prominent alien signals in our sky are likely to be extremely powerful transmitters extremely far away. So a "wide sky" sweep is more likely to succeed than a targeted search of individual stars nearby. The logic behind this conclusion seems impeccable even if we know nothing about alien civilizations or their technologies.
To cover this possibility, Breakthrough Listen will also sweep the plane of the Milky Way and the galactic center to encompass some 100 billion stars for shallower listens. And it will take protracted stares at 100 of the nearest galaxies to cover tens of trillions of stars much farther still. Just one very old supercivilization among all these stars, choosing to display its existence with sufficiently extreme power, would answer the question of whether we're alone right away. Failure to find one would be strong evidence that supercivilizations of this kind don't exist.
Breakthrough Listen also plans to carry out an optical SETI search. This project will enhance the sifting of spectroscopic data from Lick Observatory's 2.4-meter Automated Planet Finder telescope (at left) to carry out the deepest search yet for continuous laser signals that might be aimed at our solar system from specific stars.
All these projects will gather vast amounts of raw data. Some of its analysis will probably be farmed out to volunteers donating their computers' spare time by way of an app such as SETI@home, which began analyzing data from the Arecibo radio telescope in 1999 and continues going strong today.
SETI's Long Perspective
But don't get your hopes up too soon. The Breakthrough Listen planners claim that they'll speed up the search for intelligent life by 100 times over current and recent searches. That's a big improvement, but settling the question of whether we're alone is likely to take generations. The "search space" to be sifted is enormous: many billions of radio, infrared and optical frequencies at each of many billions of locations on the sky. And that's not considering such complications as intermittence, frequency drifts, and other factors. In 2004, Guillermo Lemarchand (University of Buenos Aires) calculated that all the SETI searches up to then had scanned only a hundred-trillionth of the cosmic haystack that's waiting to be searched for the needle of an artificial signal.
Scientists with careers to build, and funding agencies with donors to satisfy, prefer to see a return on investment within years or decades, not centuries. So enthusiasm for SETI waxes and wanes, with each new wave of fascination being followed by disillusionment with the boredom of seeing no result. Humanity isn't yet good at projects with very long time horizons.
But for SETI, Breakthrough Listen will help pave the way to getting there.
Quelle: Sky&Telescope
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