SETI@home software was released to the public on May 17, 1999,[5][6][7][8] making it the third large-scale use of volunteer computing over the Internet for research purposes, after Great Internet Mersenne Prime Search (GIMPS) was launched in 1996 and distributed.net in 1997. Along with MilkyWay@home and Einstein@home, it is the third major computing project of this type that has the investigation of phenomena in interstellar space as its primary purpose.
In March 2020, the project stopped sending out new work to SETI@home users, bringing the crowdsourced computing aspect of the project to a stop.[9] At the time, the team intended to shift focus onto the analysis and interpretation of the 20 years' worth of accumulated data. However, the team left open the possibility of eventually resuming volunteer computing using data from other radio telescopes, such as MeerKAT and FAST.[10]
As of November 2021, the science team has analysed the data and removed noisy signals (Radio Frequency Interference) using the Nebula tool they developed and will choose the top-scoring 100 or so multiplets to be observed using the Five-hundred-meter Aperture Spherical Telescope, to which they have been granted 24 hours of observation time.[11]
Scientific research
The two original goals of SETI@home were:
to do useful scientific work by supporting an observational analysis to detect intelligent life outside Earth[12]
to prove the viability and practicality of the "volunteer computing" concept[13]
The second of these goals is considered to have succeeded completely. The current BOINC environment, a development of the original SETI@home, is providing support for many computationally intensive projects in a wide range of disciplines.
The first of these goals has to date yielded no conclusive results: no evidence for ETI signals has been shown via SETI@home. However, the ongoing continuation is predicated on the assumption that the observational analysis is not "ill-posed." The remainder of this article deals specifically with the original SETI@home observations/analysis. The vast majority of the sky (over 98%) has yet to be surveyed, and each point in the sky must be surveyed many times to exclude even a subset of possibilities.
Procedure details
SETI@home searches for possible evidence of radio transmissions from extraterrestrial intelligence using observational data from the Arecibo radio telescope and the Green Bank Telescope.[14] The data is taken "piggyback" or "passively" while the telescope is used for other scientific programs. The data is digitized, stored, and sent to the SETI@home facility. The data is then parsed into small chunks in frequency and time, and analyzed, using software, to search for any signals—that is, variations which cannot be ascribed to noise, and hence contain information. Using volunteer computing, SETI@home sends the millions of chunks of data to be analyzed off-site by home computers, and then have those computers report the results. Thus what appears a difficult problem in data analysis is reduced to a reasonable one by aid from a large, Internet-based community of borrowed computer resources.
The software searches for five types of signals that distinguish them from noise:[15]
There are many variations on how an ETI signal may be affected by the interstellar medium, and by the relative motion of its origin compared to Earth. The potential "signal" is thus processed in many ways (although not testing all detection methods nor scenarios) to ensure the highest likelihood of distinguishing it from the scintillating noise already present in all directions of outer space. For instance, another planet is very likely to be moving at a speed and acceleration with respect to Earth, and that will shift the frequency, over time, of the potential "signal." Checking for this through processing is done, to an extent, in the SETI@home software.
The process is somewhat like tuning a radio to various channels, and looking at the signal strength meter. If the strength of the signal goes up, that gets attention. More technically, it involves a lot of digital signal processing, mostly discrete Fourier transforms at various chirp rates and durations.
Results
To date, the project has not confirmed the detection of any ETI signals. However, it has identified several candidate targets (sky positions), where the spike in intensity is not easily explained as noise spots,[16] for further analysis. The most significant candidate signal to date was announced on September 1, 2004, named Radio source SHGb02+14a.
While the project has not reached the stated primary goal of finding extraterrestrial intelligence, it has proved to the scientific community that volunteer computing projects using Internet-connected computers can succeed as a viable analysis tool, and even beat the largest supercomputers.[17][failed verification] However, it has not been demonstrated that the order of magnitude excess in computers used, many outside the home (the original intent was to use 50,000–100,000 "home" computers),[18] has benefited the project scientifically. (For more on this, see §Challenges below.)
AstronomerSeth Shostak stated in 2004 that he expects to get a conclusive signal and proof of alien contact between 2020 and 2025, based on the Drake equation.[19] This implies that a prolonged effort may benefit SETI@home, despite its (present) twenty-year run without success in ETI detection.
Technology
Anybody with an at least intermittently Internet-connected computer was able to participate in SETI@home by running a free program that downloaded and analyzed radio telescope data.
Observational data were recorded on 2-terabyteSATA hard disk drives fed from the Arecibo Telescope in Puerto Rico, each holding about 2.5 days of observations, which were then sent to Berkeley.[20] Arecibo does not have a broadband Internet connection, so data must go by postal mail to Berkeley.[21] Once there, it is divided in both time and frequency domainswork units of 107 seconds of data,[22] or approximately 0.35 megabytes (350 kilobytes or 350,000 bytes), which overlap in time but not in frequency.[20] These work units are then sent from the SETI@home server over the Internet to personal computers around the world to analyze.
Data was merged into a database using SETI@home computers in Berkeley. Interference was rejected, and various pattern-detection algorithms were applied to search for the most interesting signals.
The project used CUDA for GPU processing starting in 2015.[23]
The BOINC Manager working on the SETI@home project (v 7.6.22)Screenshot of SETI@home Classic Screensaver (v3.07)
The SETI@home volunteer computing software ran either as a screensaver or continuously while a user worked, making use of processor time that would otherwise be unused.
The initial software platform, now referred to as "SETI@home Classic", ran from May 17, 1999, to December 15, 2005. This program was only capable of running SETI@home; it was replaced by Berkeley Open Infrastructure for Network Computing (BOINC), which also allows users to contribute to other volunteer computing projects at the same time as running SETI@home. The BOINC platform also allowed testing for more types of signals.
The discontinuation of the SETI@home Classic platform rendered older Macintosh computers running the classic Mac OS (pre December, 2001) unsuitable for participating in the project.
On May 3, 2006, new work units for a new version of SETI@home called "SETI@home Enhanced" started distribution. Since computers had the power for more computationally intensive work than when the project began, this new version was more sensitive by a factor of two concerning Gaussian signals and to some kinds of pulsed signals than the original SETI@home (BOINC) software. This new application had been optimized to the point where it would run faster on some work units than earlier versions. However, some work units (the best work units, scientifically speaking) would take significantly longer.
In addition, some distributions of the SETI@home applications were optimized for a particular type of CPU. They were referred to as "optimized executables", and had been found to run faster on systems specific for that CPU. As of 2007[update], most of these applications were optimized for Intel processors and their corresponding instruction sets.[26]
The results of the data processing were normally automatically transmitted when the computer was next connected to the Internet; it could also be instructed to connect to the Internet as needed.
Statistics
With over 5.2million participants worldwide, the project was the volunteer computing project with the most participants to date[when?]. The original intent of SETI@home was to utilize 50,000–100,000 home computers.[18] Since its launch on May 17, 1999, the project has logged over two million years of aggregate computing time.[as of?] On September 26, 2001, SETI@home had performed a total of 1021floating point operations. It was acknowledged by the 2008 edition of the Guinness World Records as the largest computation in history.[27] With over 145,000 active computers in the system (1.4million total) in 233 countries, as of 23June2013[update], SETI@home had the ability to compute over 668 teraFLOPS.[28] For comparison, the Tianhe-2 computer, which as of 23June2013[update] was the world's fastestsupercomputer, was able to compute 33.86 petaFLOPS (approximately 50 times greater).
Project future
There were plans to get data from the Parkes Observatory in Australia to analyze the southern hemisphere.[29] However, as of 3June2018[update], these plans were not mentioned in the project's website. Other plans include a Multi-Beam Data Recorder, a Near Time Persistency Checker and Astropulse (an application that uses coherent dedispersion to search for pulsed signals).[30] Astropulse will team with the original SETI@home to detect other sources, such as rapidly rotating pulsars, exploding primordial black holes, or as-yet unknown astrophysical phenomena.[31] Beta testing of the final public release version of Astropulse was completed in July 2008, and the distribution of work units to higher spec machines capable of processing the more CPU intensive work units started in mid-July 2008.
On March 31, 2020, UC Berkeley stopped sending out new data for SETI@Home clients to process, ending the effort for the time being. The program stated they were at a point of "diminishing returns" with the volunteer processing and needed to put the effort into hibernation while they processed the results.[32]
Competitive aspect
SETI@home users quickly started to compete with one another to process the maximum number of work units. Teams were formed to combine the efforts of individual users. The competition continued and grew larger with the introduction of BOINC.
As with any competition, attempts have been made to "cheat" the system and claim credit for work that has not been performed. To combat cheats, the SETI@home system sends every work unit to multiple computers, a value known as "initial replication" (currently 2). Credit is only granted for each returned work unit once a minimum number of results have been returned and the results agree, a value known as "minimum quorum" (currently 2). If, due to computation errors or cheating by submitting false data, not enough results agree, more identical work units are sent out until the minimum quorum can be reached. The final credit granted to all machines which returned the correct result is the same and is the lowest of the values claimed by each machine.
Some users have installed and run SETI@home on computers at their workplaces; an act known as "Borging", after the assimilation-driven Borg of Star Trek. In some cases, SETI@home users have misused company resources to gain work-unit results with at least two individuals getting fired for running SETI@home on an enterprise production system.[33]There is a thread in the newsgroup alt.sci.seti which bears the title "Anyone fired for SETI screensaver"[34] and ran starting as early as September 14, 1999.
Other users collect large quantities of equipment together at home to create "SETI farms", which typically consist of a number of computers consisting of only a motherboard, CPU, RAM and power supply that are arranged on shelves as diskless workstations running either Linux or old versions of Microsoft Windows "headless" (without a monitor).[35]
Challenges
Closure of Arecibo Observatory
Until 2020, SETI@home procured its data from the Arecibo Observatory facility that was operated by the National Astronomy and Ionosphere Center and administered by SRI International.
The decreasing operating budget for the observatory has created a shortfall of funds which has not been made up from other sources such as private donors, NASA, other foreign research institutions, nor private non-profit organizations such as SETI@home.
However, in the overall long-term views held by many involved with the SETI project, any usable radio telescope could take over from Arecibo (which completely collapsed in December 2020),[36][37] as all the SETI systems are portable and relocatable.
More restrictive computer use policies in businesses
In one documented case, an individual was fired for explicitly importing and using the SETI@home software on computers used for the U.S. state of Ohio.[38] In another incident a school IT director resigned after his installation allegedly cost his school district $1million in removal costs; however, other reasons for this firing included lack of communication with his superiors, not installing firewall software and alleged theft of computer equipment,[39] leading a ZDNet editor to comment that "the volunteer computing nonsense was simply the best and most obvious excuse the district had to terminate his contract with cause".[40]
As of 16October2005[update], approximately one-third of the processing for the non-BOINC version of the software was performed on work or school based machines.[41] As many of these computers will give reduced privileges to ordinary users, it is possible that much of this has been done by network administrators.
There is currently no government funding for SETI research, and private funding is always limited. Berkeley Space Science Lab has found ways of working with small budgets, and the project has received donations allowing it to go well beyond its original planned duration, but it still has to compete for limited funds with other SETI projects and other space sciences projects.
In a December 16, 2007 plea for donations, SETI@home stated its present modest state and urged donations of $476,000 needed for continuation into 2008.
Unofficial clients
A number of individuals and companies made unofficial changes to the distributed part of the software to try to produce faster results, but this compromised the integrity of all the results.[46] As a result, the software had to be updated to make it easier to detect such changes, and discover unreliable clients. BOINC will run on unofficial clients; however, clients that return different and therefore incorrect data are not allowed, so corrupting the result database is avoided. BOINC relies on cross-checking to validate data[47] but unreliable clients need to be identified, to avoid situations when two of these report the same invalid data and therefore corrupt the database. A very popular unofficial client (lunatic) allows users to take advantage of the special features provided by their processor(s) such as SSE, SSE2, SSE3, SSSE3, SSE4.1, and AVX to allow for faster processing.
Hardware and database failures
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SETI@home is a test bed for further development not only of BOINC but of other hardware and software (database) technology. Under SETI@home processing loads, these experimental technologies can be more challenging than expected, as SETI databases do not have typical accounting and business data or relational structures. The non-traditional database uses often do incur greater processing overheads and risk of database corruption and outright database failure. Hardware, software and database failures can (and do) cause dips in project participation.
The project has had to shut down several times to change over to new databases capable of handling more massive datasets. Hardware failure has proven to be a substantial source of project shutdowns, as hardware failure is often coupled with database corruption.
The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other planets.
Grid computing is the use of widely distributed computer resources to reach a common goal. A computing grid can be thought of as a distributed system with non-interactive workloads that involve many files. Grid computing is distinguished from conventional high-performance computing systems such as cluster computing in that grid computers have each node set to perform a different task/application. Grid computers also tend to be more heterogeneous and geographically dispersed than cluster computers. Although a single grid can be dedicated to a particular application, commonly a grid is used for a variety of purposes. Grids are often constructed with general-purpose grid middleware software libraries. Grid sizes can be quite large.
The Berkeley Open Infrastructure for Network Computing is an open-source middleware system for volunteer computing. Developed originally to support SETI@home, it became the platform for many other applications in areas as diverse as medicine, molecular biology, mathematics, linguistics, climatology, environmental science, and astrophysics, among others. The purpose of BOINC is to enable researchers to utilize processing resources of personal computers and other devices around the world.
LHC@home is a volunteer computing project researching particle physics that uses the Berkeley Open Infrastructure for Network Computing (BOINC) platform. The project's computing power is utilized by physicists at CERN in support of the Large Hadron Collider and other experimental particle accelerators.
Einstein@Home is a volunteer computing project that searches for signals from spinning neutron stars in data from gravitational-wave detectors, from large radio telescopes, and from a gamma-ray telescope. Neutron stars are detected by their pulsed radio and gamma-ray emission as radio and/or gamma-ray pulsars. They also might be observable as continuous gravitational wave sources if they are rapidly spinning and non-axisymmetrically deformed. The project was officially launched on 19 February 2005 as part of the American Physical Society's contribution to the World Year of Physics 2005 event.
Within the BOINC platform for volunteer computing, the BOINC Credit System helps volunteers keep track of how much CPU time they have donated to various projects. This ensures users are returning accurate results for both scientific and statistical reasons.
The Allen Telescope Array (ATA), formerly known as the One Hectare Telescope (1hT), is a radio telescope array dedicated to astronomical observations and a simultaneous search for extraterrestrial intelligence (SETI). The array is situated at the Hat Creek Radio Observatory in Shasta County, 290 miles (470 km) northeast of San Francisco, California.
David Pope Anderson is an American research scientist at the Space Sciences Laboratory, at the University of California, Berkeley, and an adjunct professor of computer science at the University of Houston. Anderson leads the SETI@home, BOINC, Bossa, and Bolt software projects.
Astropulse is a volunteer computing project to search for primordial black holes, pulsars, and extraterrestrial intelligence (ETI). Volunteer resources are harnessed through Berkeley Open Infrastructure for Network Computing (BOINC) platform. In 1999, the Space Sciences Laboratory launched SETI@home, which would rely on massively parallel computation on desktop computers scattered around the world. SETI@home utilizes recorded data from the Arecibo radio telescope and searches for narrow-bandwidth radio signals from space, signifying the presence of extraterrestrial technology. It was soon recognized that this same data might be scoured for other signals of value to the astronomy and physics community.
SETI@home beta, is a hibernating volunteer computing project using the Berkeley Open Infrastructure for Network Computing (BOINC) platform, as a test environment for future SETI@home projects:
SERENDIP is a Search for Extra-Terrestrial Intelligence (SETI) program originated by the Berkeley SETI Research Center at the University of California, Berkeley.
BOINC client–server technology refers to the model under which BOINC works. The BOINC framework consists of two layers which operate under the client–server architecture. Once the BOINC software is installed in a machine, the server starts sending tasks to the client. The operations are performed client-side and the results are uploaded to the server-side.
Volunteer computing is a type of distributed computing in which people donate their computers' unused resources to a research-oriented project, and sometimes in exchange for credit points. The fundamental idea behind it is that a modern desktop computer is sufficiently powerful to perform billions of operations a second, but for most users only between 10–15% of its capacity is used. Common tasks such as word processing or web browsing leave the computer mostly idle.
Cosmology@Home is a volunteer computing project that uses the BOINC platform and was once run at the Departments of Astronomy and Physics at the University of Illinois at Urbana-Champaign. The project has moved to the Institut Lagrange de Paris and the Institut d'Astrophysique de Paris, both of which are located in the Pierre and Marie Curie University.
GridRepublic is a BOINC Account Manager. It focuses on creating a clean and simple way to join and interact with BOINC. GridRepublic was started with a mission to raise public awareness and participation in volunteer computing with BOINC. GridRepublic was formed in 2004 by Matthew Blumberg as a mechanism to control the multiple projects from one place. The code for the BOINC software had to be redesigned to allow for the Account Manager system to be implemented.
OProject@Home was a volunteer computing project running on the Berkeley Open Infrastructure for Network Computing (BOINC) and was based on a dedicated library OLib. The project was directed by Lukasz Swierczewski, an IT student at the College of Computer Science and Business Administration in Łomża, Computer Science and Automation Institute. As of 2016 it seems to have been abandoned.
theSkyNet was a research project that used volunteer Internet-connected computers to carry out research in astronomy. It was an initiative of the International Centre for Radio Astronomy Research (ICRAR), a joint venture of Curtin University and the University of Western Australia. theSkyNet had two projects, Sourcefinder and POGS. Both projects have been completed. theSkyNet Sourcefinder aimed to test and refine automatic radio sourcefinding algorithms in preparation for radio galaxy surveys using the Australian Square Kilometre Array Pathfinder and the Square Kilometre Array. theSkyNet POGS used Spectral Energy Distribution fitting to calculate characteristics of many galaxies using images taken by the Pan-STARRS PS1 optical telescope in Hawaii.
Breakthrough Listen is a project to search for intelligent extraterrestrial communications in the Universe. With $100 million in funding and thousands of hours of dedicated telescope time on state-of-the-art facilities, it is the most comprehensive search for alien communications to date. The project began in January 2016, and is expected to continue for 10 years. It is a component of Yuri Milner's Breakthrough Initiatives program. The science program for Breakthrough Listen is based at Berkeley SETI Research Center, located in the Astronomy Department at the University of California, Berkeley.
The Berkeley SETI Research Center (BSRC) conducts experiments searching for optical and electromagnetic transmissions from intelligent extraterrestrial civilizations. The center is based at the University of California, Berkeley.
Eric Korpela is a research astronomer at the University of California, Berkeley, He is the director of the SETI@home project, a distributed computing project that was launched in 1999 to use individuals computers to analyze data collected in the Search for Extraterrestrial Intelligence (SETI). Korpela notes that with modern-day mobile devices having greater capacities than personal computers did in 1999, SETI@home has developed an Android app to analyze data gathered by the Breakthrough Listen SETI project.
↑ Newport, Stuart, ed. (2005). "Largest Computation". Guinness World Records. HCI Entertainment. Archived from the original on November 28, 2005. Retrieved December 3, 2005.
Carrigan, Richard A. Jr. (2003). "The Ultimate Hacker: SETI Signals May Need to Be Decontaminated". Bioastronomy 2002: Life Among the Stars. 213. Astronomical Society of the Pacific: 519. Bibcode:2004IAUS..213..519C.
Sample, Ian (November 25, 2005). "Scientists be on guard..."The Guardian. London. Retrieved November 25, 2005.
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