The star system KIC 8462852 made headlines a few weeks ago for its mysterious dimming by 20 percent and more. That is a huge amount of dimming, and its irregularity also aroused interest, since the minute, but regular waxing and waning of light from stars is so commonly seen and studied. Astronomers proposed several natural explanations to explain KIC 8462852’s light, but the possibility that aroused everyone’s interest was that a technologically advanced, alien civilization has built megastructures – sometimes called Dyson spheres – in orbit around the star. Late yesterday (November 5, 2015), the SETI Institute announced it has now trained its Allen Telescope Array on this star, in the search for deliberate signals. It said it found “no clear evidence” for such signals within a certain range of frequencies.
Follow the links below to learn more:
What is a megastructure or Dyson sphere?
How did the SETI Institute conduct its search?
View larger. | A megastructure – or Dyson sphere – would consist of space-based solar panels for large-scale energy collection. Artist’s concept of a Dyson sphere via SentientDevelopments.com
What is a megastructure or Dyson sphere? A megastructure – or so-called Dyson sphere – would consist of swarm of solar panels for large-scale energy collection. There is the hypothetical, but intriguing, possibility that an advanced civilization might try to collect all the energy from its star.
Other possible structures include artificial space habitats, or a planet-sized or larger occulting object intended to provide a long-lasting signal to other galactic inhabitants.
Read more: what is a Dyson sphere?
The unfolding of the story of KIC 8462852 is very interesting in itself. You can read it here.
SETI Institute’s Allen Telescope Array, north of San Francisco.
How did the SETI Institute conduct its search? Several groups of astronomers have recently turned telescopes on this star, but the search by the SETI Institute is of high interest since, after all, SETI means “search for extraterrestrial intelligence.” They are the experts in this search, in other words.
The group of SETI astronomers used the Allen Telescope Array, which is is located approximately 300 miles (500 km) north of San Francisco, California in the Cascade Mountains. It consists of 42 antennas, each about 20 feet (6 meters) in size.
According to a November 5 statement from the SETI Institute, they sought two different types of radio signals:
1. Narrow-band signals, of order 1 Hz in width, such as would be generated as a “hailing signal” for societies wishing to announce their presence. This is the type of signal most frequently looked for by radio SETI experiments.
2. Broad-band signals that might be due to beamed propulsion within this star system. If astroengineering projects are really underway in the vicinity of KIC 8462852, one might reasonably expect the presence of spacecraft to service this activity. If these craft are propelled by intense microwave beams, some of that energy might manifest itself as broad-band radio leakage.
SETI Institute scientist Gerry Harp commented:
This is the first time we’ve used the Allen Telescope Array to look for relatively wide-band signals, a type of emission that is generally not considered in SETI searches.
Star KIC 8462852 in infrared (2MASS survey) and ultraviolet (GALEX). Image via Wikipedia.
What did the search reveal? The statement concluded:
Analysis of the Array data show no clear evidence for either type of signal between the frequencies of 1 and 10 GHz. This rules out omnidirectional transmitters of approximately 100 times today’s total terrestrial energy usage in the case of the narrow-band signals, and ten million times that usage for broad band emissions.
While these limits are relatively high – a fact due primarily to the large distance (>1400 light-years) of KIC 8462852 – one should note the following:
1. The required transmitter power for the narrow-band signals could be reduced enormously if the signal is being deliberately beamed in our direction.
2. Microwave propulsion schemes would undoubtedly be beamed as well, and that would also reduce the minimum transmitter power necessary for detection by the Array.
Finally, note that any society able to build a Dyson swarm would have access to energy at a level approaching 1027 watts. Even omnidirectional transmitters would be detectable if only a tiny percentage of this energy were used for signaling.
SETI Institute astronomer Seth Shostak added:
The history of astronomy tells us that every time we thought we had found a phenomenon due to the activities of extraterrestrials, we were wrong. But although it’s quite likely that this star’s strange behavior is due to nature, not aliens, it’s only prudent to check such things out.
The SETI Institute said observations will continue.
This work can be found at http://ift.tt/1PdRbyb
Bottom line: After a two-week search with the Allen Telescope Array in California, no evidence has been found of deliberately produced radio signals from KIC 8462852. This is the star system that made headlines a few weeks ago for its possible alien megastructure, aka a Dyson Sphere.
from EarthSky http://ift.tt/1NwKnde
The star system KIC 8462852 made headlines a few weeks ago for its mysterious dimming by 20 percent and more. That is a huge amount of dimming, and its irregularity also aroused interest, since the minute, but regular waxing and waning of light from stars is so commonly seen and studied. Astronomers proposed several natural explanations to explain KIC 8462852’s light, but the possibility that aroused everyone’s interest was that a technologically advanced, alien civilization has built megastructures – sometimes called Dyson spheres – in orbit around the star. Late yesterday (November 5, 2015), the SETI Institute announced it has now trained its Allen Telescope Array on this star, in the search for deliberate signals. It said it found “no clear evidence” for such signals within a certain range of frequencies.
Follow the links below to learn more:
What is a megastructure or Dyson sphere?
How did the SETI Institute conduct its search?
View larger. | A megastructure – or Dyson sphere – would consist of space-based solar panels for large-scale energy collection. Artist’s concept of a Dyson sphere via SentientDevelopments.com
What is a megastructure or Dyson sphere? A megastructure – or so-called Dyson sphere – would consist of swarm of solar panels for large-scale energy collection. There is the hypothetical, but intriguing, possibility that an advanced civilization might try to collect all the energy from its star.
Other possible structures include artificial space habitats, or a planet-sized or larger occulting object intended to provide a long-lasting signal to other galactic inhabitants.
Read more: what is a Dyson sphere?
The unfolding of the story of KIC 8462852 is very interesting in itself. You can read it here.
SETI Institute’s Allen Telescope Array, north of San Francisco.
How did the SETI Institute conduct its search? Several groups of astronomers have recently turned telescopes on this star, but the search by the SETI Institute is of high interest since, after all, SETI means “search for extraterrestrial intelligence.” They are the experts in this search, in other words.
The group of SETI astronomers used the Allen Telescope Array, which is is located approximately 300 miles (500 km) north of San Francisco, California in the Cascade Mountains. It consists of 42 antennas, each about 20 feet (6 meters) in size.
According to a November 5 statement from the SETI Institute, they sought two different types of radio signals:
1. Narrow-band signals, of order 1 Hz in width, such as would be generated as a “hailing signal” for societies wishing to announce their presence. This is the type of signal most frequently looked for by radio SETI experiments.
2. Broad-band signals that might be due to beamed propulsion within this star system. If astroengineering projects are really underway in the vicinity of KIC 8462852, one might reasonably expect the presence of spacecraft to service this activity. If these craft are propelled by intense microwave beams, some of that energy might manifest itself as broad-band radio leakage.
SETI Institute scientist Gerry Harp commented:
This is the first time we’ve used the Allen Telescope Array to look for relatively wide-band signals, a type of emission that is generally not considered in SETI searches.
Star KIC 8462852 in infrared (2MASS survey) and ultraviolet (GALEX). Image via Wikipedia.
What did the search reveal? The statement concluded:
Analysis of the Array data show no clear evidence for either type of signal between the frequencies of 1 and 10 GHz. This rules out omnidirectional transmitters of approximately 100 times today’s total terrestrial energy usage in the case of the narrow-band signals, and ten million times that usage for broad band emissions.
While these limits are relatively high – a fact due primarily to the large distance (>1400 light-years) of KIC 8462852 – one should note the following:
1. The required transmitter power for the narrow-band signals could be reduced enormously if the signal is being deliberately beamed in our direction.
2. Microwave propulsion schemes would undoubtedly be beamed as well, and that would also reduce the minimum transmitter power necessary for detection by the Array.
Finally, note that any society able to build a Dyson swarm would have access to energy at a level approaching 1027 watts. Even omnidirectional transmitters would be detectable if only a tiny percentage of this energy were used for signaling.
SETI Institute astronomer Seth Shostak added:
The history of astronomy tells us that every time we thought we had found a phenomenon due to the activities of extraterrestrials, we were wrong. But although it’s quite likely that this star’s strange behavior is due to nature, not aliens, it’s only prudent to check such things out.
The SETI Institute said observations will continue.
This work can be found at http://ift.tt/1PdRbyb
Bottom line: After a two-week search with the Allen Telescope Array in California, no evidence has been found of deliberately produced radio signals from KIC 8462852. This is the star system that made headlines a few weeks ago for its possible alien megastructure, aka a Dyson Sphere.
from EarthSky http://ift.tt/1NwKnde
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