The world’s largest radio telescope, in southwestern China, is joining an international search for extraterrestrial intelligence focused on a mysterious, flickering star that has sparked unprecedented curiosity in recent months.
“The dips found by Kepler are real. Something seems to be transiting in front of this star and we still have no idea what it is.” confirms German astronomer Michael Hippke. Even if aliens are not involved, Tabby’s star remains “the most mysterious star in the universe” as Yale astronomer Tabetha Boyajian described it in a TED talk.
The results of a new study make it far less likely that KIC 8462852, popularly known as Tabby’s star, is the home of industrious aliens who are gradually enclosing it in a vast shell called a Dyson sphere.
Media interest went viral last October 2015 when a group of astronomers from Pennsylvania State University released a preprint that cited KIC 8462852’s “bizarre light curve” as “consistent with” a swarm of alien-constructed megastructures.
Public interest in the star, which sits about 1,480 light-years away in the constellation Cygnus, began last fall when (“Tabby”) Boyajian and colleagues posted a paper on an astronomy preprint server reporting that “planet hunters” – a citizen science group formed to search data from the Kepler space telescope for evidence of exoplanets – had found unusual fluctuations in the light coming from the otherwise ordinary F-type star (slightly larger and hotter than the sun).
Space researchers in Beijing involved in the new joint effort said however that they hoped to use FAST to search for aliens as soon as possible, but it was extremely difficult to find a free time slot in the telescope’s busy schedule.
“The schedule is full. So full, in fact, I don’t think we can do anything within two years,” said the researcher, who declined to be named.
Mainstream astronomical research topics such as pulsars were given priority on FAST’s schedule, the researcher said. Looking for aliens was not regarded as an urgent task because all previous efforts had failed, and it was relatively difficult to get a SETI paper published in a top research journal.
The Berkeley center’s Breakthrough Listen project, a US$100 million initiative founded last year by internet investor Yuri Milner to conduct a 10-year search for intelligent life in space, is leading the hunt.
FAST – short for five-hundred-meter aperture spherical telescope – has a dish bigger than 30 soccer fields and a diameter almost 200 meter greater than the world’s second-biggest radio telescope, operated by the United States at Arecibo in Puerto Rico.
Observations by NASA’s Kepler space telescope showed the star dimming considerably and irregularly for days at a time – unlike the dimming of other stars caused by planets or comets.
But the pattern was a good match for the blocking that would be caused by a Dyson structure, a massive array of solar collectors that could be built by a highly developed civilization to surround a star to capture energy, first proposed by American physicist Freeman Dyson in 1960.
“Everyone, every SETI program telescope, I mean every astronomer that has any kind of telescope in any wavelength that can see Tabby’s star has looked at it,” Siemion said. “It’s been looked at with Hubble [Space Telescope], it’s been looked at with Keck [Observatory in Hawaii], it’s been looked at in the infrared and radio and high-energy [spectrums] and every possible thing you can imagine, including a whole range of SETI experiments. Nothing has been found.”
“The FAST telescope will be absolutely incredible for conducting extremely sensitive searches of Tabby’s star for evidence of technologically produced radio emissions,” Siemion said. “We are very excited to work with our colleagues in China on conducting SETI observations with FAST, including of Tabby’s star. Within its frequency range, FAST is the most sensitive telescope in the world capable of conducting SETI observations of Tabby’s star, and will be able to detect the weakest signals.”
Even buying a few hours of time on FAST would be prohibitively expensive. While SETI observation overseas was funded by many private organisations, in China the funding for astronomical observation came almost exclusively from the government, the researcher added, which also limited astronomers’ efforts to search for extraterrestrial intelligence.
Beijing Planetarium director Zhu Jin said he had confirmed with the FAST team that Tabby’s star fell well within FAST’s detection zone.
The FAST telescope had a very wide viewing angle, and its reflective panels were individually steerable, allowing it to focus on a specific spot in the universe to collect the most delicate signals, he said.
“Looking at Tabby’s star on FAST will be a very easy thing to do,” Zhu said. “When the telescope was proposed, SETI was listed as a major goal. I don’t think we can turn a blind eye to Tabby’s star.”
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Peking University astronomer Professor Zhuang Huawei, who is also deputy director of the Beijing Astronomical Association, said the biggest challenge to SETI research was the lack of scientific tools to interpret the signals that were received.
“Even if you pick up an interesting signal, there is no way to confirm that it was produced by an intelligent species,” Zhuang said. “Most of the weird things we see in space were caused by nature.”
Source: The Daily Galaxy