Freeman Dyson, who passed away at the age of 96 on February 28, recalled in a 2003 interview in which he told when and how he first put forward his theory of the "Dyson sphere", which gave a serious impetus to the search for an advanced extraterrestrial civilization. This happened in 1960, when Science published an article entitled "Search for artificial stellar sources of infrared radiation."
Dyson wrote the article when scientists from all over the world began to search for distant civilizations using radio telescopes. In his article, Dyson noted that radio is an excellent search tool, but only if civilizations want to communicate. Otherwise, you need to look for heat emissions using infrared sensors.
One of Dyson's daughters sent a 1987 videotape of Star Trek: The Next Generation to the physicist, entitled Relics. In the story, the team follows a distress signal heard by the famous USS Enterprise starship. The crew travels through space in search of the source of the signal and discovers a huge Dyson sphere, which was displayed as some kind of solid object around the star. If we were to move this sphere into our solar system, it would be so large that it would reach the orbit of Venus, according to the Star Trek fan site Memory Alpha.
He added that the name Dyson Sphere is a misnomer, as it originally took inspiration from the 1930s science fiction writer Olaf Stapledon, who first wrote about the concept in Star Creator.
Physicist Freeman Dyson died at 96.
Promotional video:
Movies like Star Trek have given us a modern understanding of the Dyson sphere, which involves a giant structure surrounding a star designed to capture its energy.
So, imagine the surprise of scientists when in 2015 they announced a star that exhibits strange behavior, changing its brightness for no apparent reason. The research team has come up with a variety of ideas, including the idea that this is possibly Dyson's realm in action.
More star called KIC 8462852 is unremarkable. It is slightly hotter and larger than the Sun and lies about 1,480 light years away in the constellation Cygnus.
The researchers captured the star's strange light wobbles using NASA's Kepler Telescope, which was designed to search for exoplanets around distant stars. KIC 8462852 changed its brightness up to 22% within a few days.
The star KIC 8462852 in infrared (2MASS) and ultraviolet (GALEX) views.
A 2015 research team led by astrophysicist Tabeta "Tabby" Boyadjiana was initially unable to explain the change in star brightness through natural phenomena. They published their work in the Royal Astronomical Society's Monthly Notices and it went viral. The star was named Tabby's Star after the discoverer, although Boyajian attributes the idea of the Dyson sphere to one of his colleagues rather than himself.
She said that one of the best results of this article was that it has fostered increased collaboration between astronomers and those looking for signs of extraterrestrial intelligence.
Another pleasant side effect of the boom was that Boyajian's team was given time on the Allen Telescope Array (ATA), a network of 42 radio telescopes in Northern California operated by the Search for Extraterrestrial Intelligence Institute (SETI). Most telescopes have limited observing times and so teams should write suggestions on how they plan to use that time. These proposals are then reviewed by other astronomers to determine who will receive the telescope within a predetermined period of time.
The elusive star KIC 8462852 hides a great secret. This image shows only a small section of the sky, where Tabby's star is only one in millions.
Boyajian and colleagues wrote a one-page proposal that was initially turned down, but then they got an invitation to use ATA anyway. As she later said, this was done because of too much hype around this star. The bonus telescope time helped Boyajian's team. In 2017, the star dimmed and re-lit several times as a team of researchers looked at it closely.
It was then that the team discovered that more blue light was absorbed in the spectrum under study than red, which suggests that an eclipse of a star cannot be a solid object like a Dyson sphere.
By 2019, some astronomers had speculated that a swarm of comets or a cloud of dust was the source of the eclipse, although Boyajian believes the star deserves more study. She is currently working on several new articles about KIC 8462852.
According to Boyajana, some people hold the Dyson sphere hypothesis, suggesting that its construction could change the structure of light over time. She added that until the team can find another star like this for comparative studies, KIC 8462852 may remain a mystery.
Artistic representation of the star Tabby.
Amid all the hype about her find, Boyajian received an offer from a friend of Dyson's who wanted her to contact the famous physicist when Dyson was about 91 years old. She wrote Dyson an email briefly explaining her work and how the scientists had struggled to explain the behavior of KIC 8462852. To her delight, Dyson responded with congratulations 15 minutes later.
Dyson wrote in this email that one of the team members who discovered gamma-ray bursts said the researchers "hesitated to publish the discovery" because "the explosions seemed to defy the laws of physics." (In just a few seconds, gamma-ray bursts can produce as much energy as the Sun will produce in 10 billion years.)
An artistic vision of a supernova and a gamma-ray burst caused by a rapidly spinning neutron star. The new model suggests that small displacements between the rotational and magnetic axes of a neutron star could influence supernovae and gamma-ray burst phenomena.
Dyson urged researchers to be patient, saying that over time, explanations for this phenomenon will appear. Three decades later, in 1991, the Compton Gamma Ray Observatory was launched, detecting an average of one burst per day from all over the sky.
The observatory also found that bursts are of two types: long and short. The long flares come from very powerful supernova explosions known as hypernovae. Brief bursts occur when two remnants of stellar corpses (called neutron stars) crash into each other and form a black hole, or a black hole engulfs a neutron star.
Author: Dmitry Lyalin
