“It is great to see data pouring in from observations of this novel and interesting source,” said Andrew Siemion, Director of Berkeley SETI Research Center. “Our team is excited to see what additional observations and analyses will reveal.”
Oumuamua was discovered by the Pan-STARRS project at the University of Hawaii in October 2017, passing Earth at about 85 times the distance to the Moon – a stone’s throw, in astronomical terms. Oumuamua is a Hawaiian name meaning “messenger” or “scout”. This scout may have been travelling through space for hundreds of millions, even billions, of years.
It is the first object discovered in the solar system that appears to originate from another star system. Its high speed – 196,000 mph at its peak – suggests it is not gravitationally bound to the Sun, but will continue its voyage back into interstellar space. It has a highly unusual structure for an asteroid – an elongated cigar shape, hundreds of meters in length but with width and height perhaps only one tenth as long.
Researchers working on long-distance space transportation have previously suggested that a cigar or needle shape is the most likely architecture for an interstellar spacecraft, since this would minimize friction and damage from interstellar gas and dust. While a natural origin is more likely, there is currently no consensus on what that origin might have been, and Breakthrough Listen is well positioned to explore the possibility that ‘Oumuamua could be an artifact.
Listen’s observation campaign will begin on Wednesday, December 13 at 3:00 pm ET. Using the Robert C. Byrd Green Bank Telescope (below), it will continue to observe ‘Oumuamua across four radio bands, from 1 to 12 GHz. Its first phase of observations will last a total of 10 hours, divided into four “epochs” based on the object’s period of rotation.
‘Oumuamua is now about 2 astronomical units (AU) away, or twice the distance between Earth and the Sun. This is closer by a factor of 50-70 than the most distant human artifact, the Voyager I spacecraft. At this distance, it would take under a minute for the Green Bank instrument to detect an omnidirectional transmitter with the power of a cellphone.
“‘Oumuamua’s presence within our solar system affords Breakthrough Listen an opportunity to reach unprecedented sensitivities to possible artificial transmitters and demonstrate our ability to track nearby, fast-moving objects,” said Listen’s Andrew Siemion, Director of Berkeley SETI Research Center. “Whether this object turns out to be artificial or natural, it’s a great target for Listen.”
Even if no signal or other evidence of extraterrestrial technology is heard, Listen observations will cover portions of the radio spectrum in which the object has not yet been observed, and could provide important information about the possibility of water/ice, or the chemistry of a coma (gaseous envelope), neither of which have yet been identified.
“No such signals have been detected” by its network of telescopes, the project said Thursday, adding: “the analysis is not yet complete.” No evidence of artificial signals emanating from the object so far detected by the Green Bank Telescope, but monitoring and analysis continue. Initial data are available for public inspection in the Breakthrough Listen archive.
The initial block of observations (the first of a planned four blocks) ran from 3:45pm to 9:45pm ET on Wednesday, December 13, using the Breakthrough Listen backend instrument on the Robert C. Byrd Green Bank Telescope in West Virginia. Listen observed ‘Oumuamua across four radio bands (corresponding to four of the radio receivers available at Green Bank, denoted L, S, X, and C), spanning billions of individual channels across the 1 to 12 GHz range.
In addition to calibration observations, the instrument accumulated 90 TB of raw data over a 2 hour observation of ‘Oumuamua itself. A search for signals that may be of artificial origin has begun, but despite the impressive computational power of the Breakthrough Listen computing cluster at Green Bank, the large data volumes mean that this will take some time to complete.
The Breakthrough Listen “turboSETI” pipeline combs the data for narrow bandwidth signals that are drifting in frequency. By matching the rate at which these signals drift to the expected drift due to the motion of ‘Oumuamua (in addition to rejecting interfering signals from human technology that do not match the sky position of the primary target), the software attempts to identify any signals that might be coming from ‘Oumuamua itself.
No such signals have been detected, although the analysis is not yet complete. So far, data from the S-band receiver (covering frequencies from 1.7 to 2.6 GHz) has been processed, and analysis of the remaining three bands is ongoing. A subset of the S-band data is now available for public inspection in the Breakthrough Listen archive, and additional data will be added as it becomes available.
The data is stored in specialized formats, and analyzing it may be challenging for non-experts. We invite those who are interested to study the tutorial material provided by the Breakthrough Listen science team at the University of California, Berkeley, SETI Research Center and to assist with the analysis not only of this intriguing object, but of the entire Breakthrough Listen dataset.
Breakthrough Listen is a scientific program in search for evidence of technological life in the Universe. It aims to survey one million nearby stars, the entire galactic plane and 100 nearby galaxies at a wide range of radio and optical bands.
The Breakthrough Initiatives are a suite of scientific and technological programs looking for life in the Universe.