Astronomer Tabetha Boyajian discusses Tabby’s Star, “the most mysterious star in the universe,” during a TED talk in February 2016 in Vancouver, B.C. (TED via YouTube)
The astronomers who once speculated that an alien megastructure might be responsible for the weirdly fluctuating light from a distant star have now fully ruled out that way-out explanation.
The authors of the paper include Louisiana State University’s Tabetha Boyajian, who led the discovery team for the star known as KIC 8462852 or “Tabby’s Star”; and Penn State’s Jason Wright, who first proposed the alien-megastructure hypothesis.
This illustration depicts a hypothetical uneven ring of dust orbiting KIC 8462852, also known as Boyajian’s Star or Tabby’s Star. (NASA / JPL-Caltech Illustration)
Are aliens building a huge energy-generating megastructure around a weirdly dimming star? That way-out hypothesis has suffered another blow, thanks to a study that draws upon infrared as well as ultraviolet observations.
The star, known as KIC 8462852 or Tabby’s Star, first came to attention two years ago when citizen scientists sifting through data from NASA’s Kepler space telescope noticed some unusually drastic dips in its brightness. The star’s nickname comes from Tabetha “Tabby” Boyajian, the Yale astronomer who oversaw those observations.
Another astronomer, Penn State’s Jason Wright, mused that the data could be explained by the construction of a huge orbital structure known as a Dyson sphere — although he cautioned that “aliens should always be the very last hypothesis you consider.”
This illustration shows a star behind a shattered comet. (Credit: NASA / JPL-Caltech)
That mysterious “alien megastructure” star is still a mystery, but the most plausible explanations appear to be dense patches of interstellar gas or dust that just happened to pass in front of the star.
That’s the upshot of analyses conducted by the astronomer who first raised the idea of an extraterrestrial construction project a year ago.
In the Astrophysical Journal Letters, Penn State’s Jason Wright and a co-author, Steinn Sigurdsson, run through a wide range of hypotheses for the behavior of a star called KIC 8462852, also known as Boyajian’s Star or Tabby’s Star.
This illustration shows a star behind a shattered comet. Astronomers say it’s possible that such a phenomenon could explain some aspects of the dimming pattern for a mysterious star called KIC 8462852, but not all aspects. (Credit: NASA / JPL-Caltech)
It’s been almost a year since astronomers first speculated that a strangely dimming star called KIC 8462852 might harbor an alien megastructure, and newly reported observations are making the case even stranger.
KIC 8462852 is also known as Tabby’s Star, because Yale astronomer Tabetha Boyajian first brought the case to light, based on observations that were collected by NASA’s Kepler space telescope and analyzed by the Planet Hunters project. The somewhat sunlike star lies about 1,500 light-years from Earth in the constellation Cygnus.
Kepler’s data revealed an erratic pattern in the intensity of KIC 8462852’s starlight, including periods when the light dimmed as much as 20 percent. Penn State astronomer Jason Wright noted that the dimming could theoretically be caused by shifts in an alien megastructure surrounding the star – something like a giant energy-generating Dyson sphere.
An artist’s speculative representation shows a crumbling megastructure known as a Dyson sphere orbiting KIC 8462852. (Credit: Danielle Futselaar / SETI International)
He’s not saying it’s aliens – but an astronomer has raised new questions about KIC 8462852, the strange star that stirred up a debate about “alien megastructures” months ago.
In a paper submitted to Astrophysical Journal Letters, Lousiana State University’s Bradley Schaefer reviews archival photographic plates that show KIC 8462852 at various times going back to 1890. He reports that the star, which is 1,500 light-years away in the constellation Cygnus, faded by about 20 percent between the 1890s and the 1980s.
“This century-long dimming is completely unprecedented for any F-type main sequence star,” Schaefer writes.
KIC 8462852’s dimming was already worthy of note, due to observations by NASA’s Kepler space telescope that revealed unusual episodes during which the star faded by as much as 20 percent. That led Penn State astronomer Jason Wright to observe that such a pattern was consistent with what you’d expect if aliens were building an energy-generating megastructure known as a “Dyson sphere” around the star.
This color-coded representation of Ceres’ Occator Crater shows differences in surface composition, highlight bright patches inside the crater. (Credit: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA)
For months, scientists have puzzled over weirdly bright spots of material shining on the asteroid Ceres, but now they say the spots are probably made of salty ice.
That determination, based on a detailed analysis of spectral data from NASA’s Dawn orbiter, comes in a paper published today by the journal Nature. Dawn’s images highlight one particular patch in a 106-mile-wide impact basin known as Occator Crater, but other spots are spread across the surface of the 590-mile-wide dwarf planet.
“The global nature of Ceres’ bright spots suggests that this world has a subsurface layer that contains briny water-ice,” the study’s principal author, Andreas Nathues of the Max Planck Institute for Solar System Research, said in a NASA statement. He and his co-authors suggest that cosmic impacts dig up enough surface material to expose the shiny ice.
his illustration shows a star behind a shattered comet. Observations of the star KIC 8462852 by NASA’s Kepler and Spitzer space telescopes suggest that its unusual light signals are probably due to dusty comet fragments that blocked the light of the star. (Credit: NASA / JPL-Caltech)
Recent infrared observations of a star that once showed a pattern of weird dimming have turned up no anomalous readings, astronomers say – and that supports the view that a comet blitz rather than the construction of an alien megastructure was behind the earlier observations.
The latest evidence, laid out in a paper published in the Astrophysical Journal Letters, isn’t exactly surprising. The passing of a shattered comet was seen as the leading orthodox explanation for the star KIC 8462852’s strange behavior.
But there was also the unorthodox explanation. The readings from the star, gathered by NASA’s Kepler space telescope and analyzed by a citizen-science project known as the Planet Hunters, created a stir because of a potential alien connection.
The Allen Telescope Array looks for alien radio signals. (Credit: Seth Shostak / SETI Institute)
The SETI Institute says it hasn’t detected any alien radio signals coming from a star whose light seems to be dimming in a weird way, but it’s too early to determine what kind of phenomenon is behind the pattern.
The star, which is known as KIC 8462852 and lies about 1,500 light-years from Earth in the constellation Cygnus, has been the focus of otherworldly buzz for the past month due to anomalous observations gathered by NASA’s Kepler Space Telescope. Kepler’s data suggested that the star goes dramatically dim on an irregular schedule, at intervals ranging from five to 80 days.
Astronomers said the best natural explanation for the effect appeared to be a swarm of comets that just happened to be passing across the star’s disk when Kepler was looking. But one research team, led by Penn State astronomer Jason Wright, speculated that the effect could be caused by an alien megastructure that was being built around the star.
