Astropulse

Last updated
Astropulse
Developer(s) University of California, Berkeley
Initial releaseJuly 2008 (public release)
Platform Cross-platform
Available inEnglish
Type Volunteer computing
License GNU GPL [1]
Website setiathome.ssl.berkeley.edu

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.

Contents

Development

For about 6 years, Astropulse existed in an experimental beta testing phase not available to the general community. In July 2008, Astropulse was integrated into SETI@home, so that the massive network of SETI participants could also contribute to the search for other astronomical signals of value. Astropulse also makes contributions to the search for ET: first, project proponents believe it may identify a different type of ET signal not identified by the original SETI@Home algorithm; second, proponents believe it may create additional support for SETI by providing a second possible concrete result from the overall search project.

Final development of Astropulse has been a two-part endeavor. The first step was to complete the Astropulse C++ core that can successfully identify a target pulse. Upon completion of that program, the team created a trial dataset that contained a hidden pulse, which the completed program successfully found, thus confirming the ability of the Astropulse core to successfully identify target pulses. Since July 2008, research has focused on a series of refinements to the beta version which are then rolled out to the full universe of SETI participants. At the programming level, developers first seek to assure that new versions are compatible with a variety of platforms, after which the refined version is optimized for greater speed. As of April, 2009, Astropulse is testing beta version 5.05.

The future of the project depends on extended funding to SETI@home.

The BOINC idea is to divide (split) large blocks of data into smaller units, each of which can be distributed to individual participating work stations. To this end, the project then began to embed the Astropulse core into the SETI beta client and began to distribute real data, split into Astropulse work units, to a team of beta testers. The challenge has been to assure that the Astropulse core will work seamlessly on a broad array of operating systems. Current research focuses on implementing algorithm refinements that eliminate or reduce false positives.

Scientific research

Astropulse searches for both single pulses and regularly repeating pulses. This experiment represents a new strategy for SETI, postulating microsecond timescale pulses as opposed to longer pulses or narrowband signals. They may also discover pulsars and exploding primordial black holes, both of which would emit brief wideband pulses. The primary purpose of the core Astropulse algorithm is coherent de-dispersion of the microsecond radio pulses for which Astropulse is searching. Dispersion of a signal occurs as the pulse passes through the interstellar medium (ISM) plasma, because the high frequency radiation goes slightly faster than the lower frequency radiation. [2] Thus, the signal arrives at the radio-telescope dispersed depending upon the amount of ISM plasma between the Earth and the source of the pulse. Dedispersion is computationally intensive, thus lending itself to the distributed computing model.

Astropulse utilizes the distributed computing power of SETI@home, delegating computational sub-tasks to hundreds of thousands of volunteers' computers, to gain advantages in sensitivity and time resolution over previous surveys. Wideband pulses would be "chirped" by passage through the interstellar medium; that is, high frequencies would arrive earlier and lower frequencies would arrive later. Thus, for pulses with wideband frequency content, dispersion hints at a signal's extraterrestrial origin. Astropulse searches for pulses with dispersion measures ranging from 50  pc/cm3 to 800 pc/cm−3 (chirp rates of 7000  Hz to 400 Hz per microsecond), allowing detection of sources almost anywhere within the Milky Way.

Project proponents believe that Astropulse will either detect exploding black holes, or establish a maximum rate of 5×10−14  pc −3 yr −1, a factor of 104 better than any previous survey. [3]

Challenges

Any radio astronomy project confronts issues arising from interference, and the challenges are especially great when the target signals are weak or of transient duration. Military radar noise which is regularly occurring and of known duration can be "blanked" at the radio telescope source. A variety of techniques have been explored in the literature to develop algorithms that detect and account for radar sources that cannot be blanked in this way. [4]

Results

Astropulse started computing in mid-July 2008. As of January 2009, the results have been used in a variety of ways. Development staff, aided by volunteers, have worked to assure that the client works effectively on a broad array of operating systems. Code has been refined and optimized to reduce calculation time on the local work station. Results have been analyzed so that the algorithms can be adjusted to reduce false positives that may result from interference or from random background noise. To date, a target signal has not yet been found.

Potential pulse finds

One goal of Astropulse is to detect postulated mini black holes that might be evaporating due to "Hawking radiation". Such mini black holes are postulated [5] to have been created during the Big Bang, unlike currently known black holes. The Astropulse project hopes that this evaporation would produce radio waves that Astropulse can detect. The evaporation wouldn't create radio waves directly. Instead, it would create an expanding fireball of high-energy gamma rays and particles. This fireball would interact with the surrounding magnetic field, pushing it out and generating radio waves. [6]

Rotating radio transients (RRATs) are a type of neutron stars discovered in 2006 by a team led by Maura McLaughlin from the Jodrell Bank Observatory at the University of Manchester in the UK. RRATs are believed to produce radio emissions which are very difficult to locate, because of their transient nature. [7] Early efforts have been able to detect radio emissions (sometimes called RRAT flashes) [8] for less than one second a day, and, like with other single-burst signals, one must take great care to distinguish them from terrestrial radio interference. Distributing computing and the Astropulse algorithm may thus lend itself to further detection of RRATs.

Pulses with an apparent extragalactic origin have been observed in archived data. It is suggested that hundreds of similar events could occur every day and, if detected, could serve as cosmological probes. Radio pulsar surveys such as Astropulse-SETI@home offer one of the few opportunities to monitor the radio sky for impulsive burst-like events with millisecond durations. [9] Because of the isolated nature of the observed phenomenon, the nature of the source remains speculative. Possibilities include a black hole-neutron star collision, a neutron star-neutron star collision, a black hole-black hole collision, or some phenomenon not yet considered.

However, in 2010 there was a new report of 16 similar pulses from the Parkes Telescope which were clearly of terrestrial origin. [10]

Previous searches by SETI@home have looked for extraterrestrial communications in the form of narrow-band signals, analogous to our own radio stations. The Astropulse project argues that since we know nothing about how ET might communicate, this might be a bit closed-minded. Thus, the Astropulse survey can be viewed as supplementing the narrow-band SETI@home survey as a by-product of the search for physical phenomena.

RF radiation from outer space was first discovered by Karl G. Jansky (1905–1950), who worked as a radio engineer at the Bell Telephone Laboratories to studying radio frequency interference from thunderstorms for Bell Laboratories. He found "...a steady hiss type static of unknown origin", which eventually he concluded had an extraterrestrial origin. Pulsars (rotating neutron stars) and quasars (dense central cores of extremely distant galaxies) were both discovered by radio astronomers. In 2003 astronomers using the Parkes radio telescope discovered two pulsars orbiting each other, the first such system known. Explaining their recent discovery of a powerful bursting radio source, NRL astronomer Dr. Joseph Lazio stated: [11] "Amazingly, even though the sky is known to be full of transient objects emitting at X- and gamma-ray wavelengths, very little has been done to look for radio bursts, which are often easier for astronomical objects to produce." The use of coherent dedispersion algorithms and the computing power provided by the SETI network may lead to discovery of previously undiscovered phenomena.

Astronomy in the schools

Astropulse and its older partner, SETI@home, offer a concrete way for secondary school science teachers to involve their students with astronomy and computing. A number of schools maintain volunteer computing class projects.

Related Research Articles

<span class="mw-page-title-main">Search for extraterrestrial intelligence</span> Effort to find civilizations not from Earth

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.

Stellar radio sources, radio source stars or radio stars are stellar objects that produce copious emissions of various radio frequencies, whether constant or pulsed. Radio emissions from stars can be produced in many varied ways.

<span class="mw-page-title-main">SETI@home</span> BOINC based volunteer computing project searching for signs of extraterrestrial intelligence

SETI@home is a project of the Berkeley SETI Research Center to analyze radio signals with the aim of searching for signs of extraterrestrial intelligence. Until March 2020, it was run as an Internet-based public volunteer computing project that employed the BOINC software platform. It is hosted by the Space Sciences Laboratory at the University of California, Berkeley, and is one of many activities undertaken as part of the worldwide SETI effort.

An astronomical radio source is an object in outer space that emits strong radio waves. Radio emission comes from a wide variety of sources. Such objects are among the most extreme and energetic physical processes in the universe.

<span class="mw-page-title-main">Wow! signal</span> 1977 narrowband radio signal from SETI

The Wow! signal was a strong narrowband radio signal detected on August 15, 1977, by Ohio State University's Big Ear radio telescope in the United States, then used to support the search for extraterrestrial intelligence. The signal appeared to come from the direction of the constellation Sagittarius and bore the expected hallmarks of extraterrestrial origin.

<span class="mw-page-title-main">Pulsar</span> Highly magnetized, rapidly rotating neutron star

A pulsar is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Earth, and is responsible for the pulsed appearance of emission. Neutron stars are very dense and have short, regular rotational periods. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of ultra-high-energy cosmic rays.

<span class="mw-page-title-main">Low-Frequency Array (LOFAR)</span> Radio telescope network located mainly in the Netherlands

The Low-Frequency Array, or LOFAR, is a large radio telescope, with an antenna network located mainly in the Netherlands, and spreading across 7 other European countries as of 2019. Originally designed and built by ASTRON, the Netherlands Institute for Radio Astronomy, it was first opened by Queen Beatrix of The Netherlands in 2010, and has since been operated on behalf of the International LOFAR Telescope (ILT) partnership by ASTRON.

<span class="mw-page-title-main">Allen Telescope Array</span> Radio telescope array

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.

Rotating radio transients (RRATs) are sources of short, moderately bright, radio pulses, which were first discovered in 2006. RRATs are thought to be pulsars, i.e. rotating magnetised neutron stars which emit more sporadically and/or with higher pulse-to-pulse variability than the bulk of the known pulsars. The working definition of what a RRAT is, is a pulsar which is more easily discoverable in a search for bright single pulses, as opposed to in Fourier domain searches so that 'RRAT' is little more than a label and does not represent a distinct class of objects from pulsars. As of March 2015 over 100 have been reported.

<span class="mw-page-title-main">Water hole (radio)</span> Relatively noiseless band of the electromagnetic spectrum in the interstellar radio noise background

The waterhole, or water hole, is an especially quiet band of the electromagnetic spectrum between 1420 and 1662 megahertz, corresponding to wavelengths of 21 and 18 centimeters, respectively. It is a popular observing frequency used by radio telescopes in radio astronomy.

SERENDIP is a Search for Extra-Terrestrial Intelligence (SETI) program originated by the Berkeley SETI Research Center at the University of California, Berkeley.

<span class="mw-page-title-main">Five-hundred-meter Aperture Spherical Telescope</span> Radio telescope located in Guizhou Province, China

The Five-hundred-meter Aperture Spherical radio Telescope, nicknamed Tianyan, is a radio telescope located in the Dawodang depression (大窝凼洼地), a natural basin in Pingtang County, Guizhou, southwest China. FAST has a 500 m (1,600 ft) diameter dish constructed in a natural depression in the landscape. It is the world's largest filled-aperture radio telescope and the second-largest single-dish aperture, after the sparsely-filled RATAN-600 in Russia.

<span class="mw-page-title-main">Gravitational wave</span> Propagating spacetime ripple

Gravitational waves are waves of the intensity of gravity generated by the accelerated masses of an orbital binary system that propagate as waves outward from their source at the speed of light. They were first proposed by Oliver Heaviside in 1893 and then later by Henri Poincaré in 1905 as waves similar to electromagnetic waves but the gravitational equivalent.

<span class="mw-page-title-main">Gravitational-wave astronomy</span> Branch of astronomy using gravitational waves

Gravitational-wave astronomy is an emerging field of science, blending astrophysics and observational astronomy. Scientists aim to utilize observations of gravitational waves to collect relatively unique data and make inferences about objects such as neutron stars and black holes, events such as supernovae, and processes including those of the early universe shortly after the Big Bang.

RRAT J1819-1458 is a Milky Way neutron star and the best studied of the class of rotating radio transients (RRATs) first discovered in 2006.

<span class="mw-page-title-main">PALFA Survey</span>

PALFA is a large-scale survey for radio pulsars at 1.4 GHz using the Arecibo 305-meter telescope and the ALFA multibeam receivers. It is the largest and most sensitive survey of the Galactic plane to date.

The Xinjiang Qitai 110m Radio Telescope (QTT) is a planned radio telescope to be built in Qitai County in Xinjiang, China. Upon completion, which is scheduled for 2023, it will be the world's largest fully steerable single-dish radio telescope. It is intended to operate at 300 MHz to 117 GHz. The construction of the antenna project is under the leadership of the Xinjiang Astronomical Observatory of the Chinese Academy of Sciences.

<span class="mw-page-title-main">Fast radio burst</span> Astronomical high energy transient pulse

In radio astronomy, a fast radio burst (FRB) is a transient radio pulse of length ranging from a fraction of a millisecond to 3 seconds, caused by some high-energy astrophysical process not yet understood. Astronomers estimate the average FRB releases as much energy in a millisecond as the Sun puts out in three days. While extremely energetic at their source, the strength of the signal reaching Earth has been described as 1,000 times less than from a mobile phone on the Moon. The first FRB was discovered by Duncan Lorimer and his student David Narkevic in 2007 when they were looking through archival pulsar survey data, and it is therefore commonly referred to as the Lorimer Burst. Many FRBs have since been recorded, including several that have been detected to repeat in seemingly irregular ways. Only one FRB has been detected to repeat in a regular way: FRB 180916 seems to pulse every 16.35 days.

<span class="mw-page-title-main">Breakthrough Listen</span> Initiative to search for intelligent extraterrestrial life

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.

<span class="mw-page-title-main">Berkeley SETI Research Center</span>

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.

References

  1. ↑ "Archived copy". Archived from the original on 2013-04-04. Retrieved 2012-05-30.{{cite web}}: CS1 maint: archived copy as title (link)
  2. ↑ "Pulsar Dispersion Measure". Centre for Astrophysics and Supercomputing - Swinburne. Archived from the original on 18 July 2010. Retrieved 2010-06-23.
  3. ↑ Joshua Von Korff (2007-12-04). "Searches for Exploding Black Holes" (PDF). UC Berkeley Astronomy Department. Archived from the original (PDF) on 2011-06-06. Retrieved 2010-06-23.
  4. ↑ S.W. Ellingson & G.A. Hampson (2003). "Mitigation of Radar Interference in L-Band Radio Astronomy". The Astrophysical Journal Supplement Series. 147 (1): 167. Bibcode:2003ApJS..147..167E. doi: 10.1086/375025 .
  5. ↑ "The case for mini black holes". Cern Courier. 2004-11-24. Retrieved 2010-06-23.
  6. ↑ "Primordial Black Holes" . Retrieved 2010-06-23.
  7. ↑ David Biello (2006-02-16). "New Kind of Star Found". Scientific American . Retrieved 2010-06-23.
  8. ↑ Jodrell Bank Observatory. "RRAT flash". Physics World. Retrieved 2010-06-23.
  9. ↑ Duncan Lorimer; Matthew Bailes; Maura McLaughlin; David Narkevic & Fronefield Crawford (October 2007). "A bright millisecond radio burst of extragalactic origin". Science. 318 (5851): 777–80. arXiv: 0709.4301 . Bibcode:2007Sci...318..777L. doi:10.1126/science.1147532. PMID   17901298. S2CID   15321890.
  10. ↑ Sarah Burke-Spolaor; Matthew Bailes; Ronald Ekers; Jean-Pierre Macquart; Fronefield Crawford III (2010). "Radio Bursts with Extragalactic Spectral Characteristics Show Terrestrial Origins". The Astrophysical Journal. 727 (1): 18. arXiv: 1009.5392 . Bibcode:2011ApJ...727...18B. doi:10.1088/0004-637X/727/1/18. S2CID   35469082.
  11. ↑ Andrea Gianopoulos; Shannon Wells; Michelle Lurch-Shaw; Janice Schultz; DonnaMcKinney (2005-03-02). "Astronomers Detect Powerful Bursting Radio Source Discovery Points to New Class of Astronomical Objects". National Radio Astronomy Observatory Press Release: 9. Bibcode:2005nrao.pres....9. Retrieved 2010-06-23.

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