In the last two days we’ve looked at a discussion of a possible SETI observable, a ‘shielding swarm’ that an advanced civilization might deploy in the event of a nearby supernova. As with Richard Carrigan’s pioneering searches for Dyson swarms in the infrared, this kind of SETI makes fundamentally different assumptions than the SETI we’ve grown familiar with, where the hope is to snag a beacon-like signal at radio or optical wavelengths. So-called ‘Dysonian SETI’ assumes no intent to communicate. It is about observing a civilization’s artifacts.
Both radio/optical SETI and this Dysonian effort are worth pursuing, because we have no idea what the terms of any discovery of an extraterrestrial culture will be. The hope of receiving a deliberate signal carries the enthralling possibility that somewhere there is an Encyclopedia Galactica that we may one day gain access to, or at the least that there is a civilization that wants to talk to us. A Dysonian detection would tell us that civilizations can survive their youth to become builders on a colossal scale, pushing up toward Kardashev levels II and III.
Keeping both SETI tracks engaged is good science. It’s encouraging on the radio front to see that the Parkes radio telescope in Australia has now joined the Green Bank Telescope (West Virginia) and the Automated Planet Finder (Lick Observatory) in SETI observations funded by Breakthrough Listen. A key component of the Breakthrough Initiatives effort (which includes Breakthrough Starshot), Breakthrough Listen has just announced the activation of its SETI project at Parkes with observations of the newly discovered planet around Proxima Centauri.
About this study, several points. First, Parkes marks a welcome expansion of the northern hemisphere efforts. Situated about 20 kilometers north of the town of Parkes in New South Wales, the telescope can observe those parts of the sky that are not visible to its northern counterparts, making it a major component in any comprehensive SETI effort.
Image: The Parkes radio telescope in New South Wales. Credit: CSIRO.
As to Proxima Centauri, we now have an Earth-sized planet orbiting in what appears to be its habitable zone, meaning that temperatures could allow liquid water to exist on its surface. The discovery of Proxima b has enlivened the interstellar community as we examine ways to learn more about it, including the Breakthrough Starshot flyby probe studies. But I think we can agree that the chances of finding a civilization on any particular planet are low.
So says Andrew Siemion, director of the Berkeley SETI Research Center and leader of the Breakthrough Listen science program. And he adds:
“…once we knew there was a planet right next door, we had to ask the question, and it was a fitting first observation for Parkes. To find a civilisation just 4.2 light years away would change everything.”
It was in the same spirit that a number of SETI instruments have been turned to Boyajian’s Star (KIC 8462852), whose unusual light curves have drawn a great deal of attention because we have so far been unable to explain them. In both cases, we have a high-interest target, in the Proxima system because of its sheer proximity to Earth and in the Boyajian’s Star system because one explanation for those light curves is intelligent engineering.
So I am all for examining Proxima Centauri even though I think the real action there will be in one day analyzing its atmosphere for signs of biosignatures. 14 days of commissioning and test observations at Parkes led up to the first observation of Proxima on November 8 (local time). The broader strategy is to continue the SETI effort at radio wavelengths across a wide range of targets, as listed in this Breakthrough Initiatives news release.
- All 43 stars (at south declinations) within 5 parsecs, at 1-15 GHz. Sensitive to the levels of radio transmission at which signals ‘leak’ from Earth-based radar transmitters (with available receivers).
- 1000 stars (south) of all spectral-types (OBAFGKM) within 50 parsecs (1-4 GHz).
- One Million Nearby Stars (south). In 2016-2017, first 5,000 stars; 1 minute exposure (1-4 GHz).
- Galactic plane and Center (1-4 GHz).
- Centers of 100 nearby galaxies (south declinations): spirals, ellipticals, dwarfs, irregulars (1-4 GHz).
- Exotic sources will include white dwarfs, neutron stars, black holes, and other anomalous natural sources (1-4 GHz).
Bear in mind as these efforts proceed that Breakthrough Listen will also be coordinating searches with the FAST (Five hundred meter Aperture Spherical Telescope) in southwest China, exchanging observing plans, search methods and data. Thus we move toward a global SETI effort that can quickly share promising signals for analysis. Data from Parkes and the other Breakthrough Listen telescopes will be made available to the public online.
Given the apparent vulnerability of electronics to large solar flares (e.g. damage to telegraph systems during the Carrington Event), I have to wonder whether Proxima b would be a good prospect for maintaining a high-tech civilisation even if a species with sufficient technological aptitude were to exist there.
I wouldn’t count it out until we learned “more” (by which mean “something”) about Proxima’s planet and about extraterrestrial life in general.
I am curious, they state the following.
All 43 stars (at south declinations) within 5 parsecs, at 1-15 GHz. Sensitive to the levels of radio transmission at which signals ‘leak’ from Earth-based radar transmitters (with available receivers).
1000 stars (south) of all spectral-types (OBAFGKM) within 50 parsecs (1-4 GHz).
One Million Nearby Stars (south). In 2016-2017, first 5,000 stars; 1 minute exposure (1-4 GHz).
Would they not be more prudent undertaking the 1-15GHz search on all Main Sequence stars within 100 parsecs (326 Ly) that are spectral classes K,M,G,F and no more than 1.5 Solar Masses? This would limit the number of stars, maximise the search criteria and mean that time, money and effort is not wasted on those stars which will clearly not host technically advanced civilisations as a result of stellar lifespans.
A 1.5 Solar Mass star is likely to be around F5 and have a life span of only ~3 Billion Years, about a third that of the Sun and 60% of the time the Sun has already existed. Even this may be too short a life, but we have to start somewhere, but taking in stars that clearly will not live long enough to perhaps even have life evolve on their worlds, let alone intelligence, seems a monumental waste of resources – which are limited anyway.
Good point. Yes, I think we should focus the search where the odds are best for intelligent life to have enough time to develop. Let’s find a true Earth twin that includes hunting for sun twins.
Unless the inhabitants of the F5 star are colonists from elsewhere :-)
Will the Square Kilometer Array be incorporated into the Breakthrough Listen effort, when it comes online?
Tom, I don’t have any information on that, but will report here if I learn anything about it.
A precursor instrument to the SKA, the MWA (http://www.mwatelescope.org), of which I am a team member, has been used to perform an ‘opportunistic’ search at low frequencies, (the MWA operates over 80 MHz – 300 MHz currently) – https://arxiv.org/abs/1607.08818 In this paper, mention is made of the SKA and SETI, quote: ‘A key science program for the SKA is the “cradle of life” (Hoare et al. 2015), including comprehensive and ambitious SETI experiments (Siemion et al. 2015).’
The MWA and Parkes have performed observations together previously, for example – https://arxiv.org/abs/1507.04830 This collaboration will grow with the advent of the SKA, particularly the low-frequency component to be built in Western Australia.
No ET’s, probably, but lightning flashes would be cool.
Looking through the Breakthrough Listen OPEN DATA ARCHIVE, they do not have Proxima Centauri’s – HIP 70890 listed as of today. I am wondering if there are going to be any optical searches – maybe this is something the more professional amateur astronomy community can do.
http://breakthroughinitiatives.org/OpenDataSearch
Here are some examples – the AAVSO has thousand’s of members!
Amateur Optical SETI
http://www.coseti.org/paper_02.htm
Optical SETI for Academics and Amateurs
frank.harvard.edu/~howard/papers/sleague.pdf
Optical SETI
http://meti.org/optical-seti
Thinking Out Loud: An Optical SETI Campaign Suitable for Amateur Astronomers?
adsabs.harvard.edu/full/2009SASS…28…67E
American Association of Variable Star Observers (AAVSO)
https://www.aavso.org/
Thinking Out Loud: An Optical SETI Campaign Suitable for Amateur Astronomers?
http://articles.adsabs.harvard.edu//full/2009SASS…28…67E/0000076.000.html
The Arrival arrives today. By all accounts it sounds like one of those sadly rare intelligent science fiction films about alien contact.
http://uproxx.com/movies/arrival-timely-trump-election/
https://backchannel.com/i-had-one-night-to-invent-interstellar-travel-b2466882ef5c#.r3mfng740
Quoting from the second article linked:
When I watch science fiction movies I have to say I quite often cringe, thinking, “someone’s spent $100 million on this movie?—?and yet they’ve made some gratuitous science mistake that could have been fixed in an instant if they’d just asked the right person.” So I decided that even though it was a very busy time for me, I should get involved in what’s now called Arrival and personally try to give it the best science I could.
There are, I think, several reasons Hollywood movies often don’t get as much science input as they should. The first is that movie makers usually just aren’t sensitive to the “science texture” of their movies. They can tell if things are out of whack at a human level, but they typically can’t tell if something is scientifically off. Sometimes they’ll get as far as calling a local university for help, but too often they’re sent to a hyper-specialized academic who’ll not-very-usefully tell them their whole story is wrong. Of course, to be fair, science content usually doesn’t make or break movies. But I think having good science content?—?like, say, good set design?—?can help elevate a good movie to greatness.
This Week’s Most Popular –Stephen Hawking: “I am More Convinced Than Ever That We are Not Alone”
November 12, 2016
“As I grow older I am more convinced than ever that we are not alone. After a lifetime of wondering, I am helping to lead a new global effort to find out,” Hawking says in the film while exploring Gliese 832c, a planet that lies 16 light-years away and could possibly harbor advanced alien life.
Stephen Hawking warns against our SETI efforts to contact advanced alien civilizations in a new online film called Stephen Hawking’s Favorite Places, which shows the famed scientist in a CGI spacecraft called the SS Hawking exploring his favorite destinations in the Universe.
“The Breakthrough Listen project will scan the nearest million stars for signs of life, but I know just the place to start looking. One day we might receive a signal from a planet like Gliese 832c, but we should be wary of answering back. If so, they will be vastly more powerful and may not see us as any more valuable than we see bacteria,” he says in the film.
Full article here:
http://www.dailygalaxy.com/my_weblog/2016/11/weeks-most-popular-stephen-hawking-i-am-more-convinced-than-ever-that-we-are-not-alone-.html
We still have far more to fear from members of our own species on this planet than any hypothetical aliens many light years away.