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posted by Fnord666 on Sunday May 21 2017, @03:54AM   Printer-friendly
from the megastructures dept.

Tabby's Star, speculated to be surrounded by a cloud of debris or alien megastructures, has dimmed yet again, causing multiple observatories to take notice:

Among the telescopes [Jason] Wright said researchers now hope to use to catch this dimming event in the act:

—The Green Bank Telescope in West Virginia, the world's largest fully steerable radio telescope
—The Automated Planet Finder at Lick Observatory near San Jose, Calif., a robotic optical telescope
—Both telescopes at the Keck Observatory in Hawaii, which operate in optical and near-infrared wavelengths
—The MMT Observatory in Arizona, an optical telescope
—NASA's Swift Gamma-Ray Burst Mission, which operates in gamma ray, x-ray, ultraviolet and optical wavelengths
—Las Cumbres Observatory, a worldwide network of robotic optical telescopes
—Fairborn Observatory in Arizona, which operates in optical wavelengths
—The Large Binocular Telescope in Arizona, which operates in optical and near-infrared wavelengths
—The Hobby–Eberly Telescope in Texas, an optical telescope

Also at The Verge.

One astronomer has proposed looking at the nearest 43 to 85 pulsars for megastructures (arXiv):

Osmanov estimates that the habitable zone around a relatively slowly-rotating pulsar (with a period of about half a second) would be on the order of 0.1 AU. According to his calculations, a ring-like megastructure that orbited a pulsar at this distance would emit temperatures on the order of 390 K (116.85 °C; 242.33 °F), which means that the megastructure would be visible in the IR band.

Previously: Mysterious Star May Be Orbited by Alien Megastructures
I'm STILL Not Sayin' Aliens. but This Star is Really Weird.
"Breakthrough Listen" to Search for Alien Radio Transmissions Near Tabby's Star
Non-Alien Explanation for Tabby's Star Dimming: It Ate a Planet


Original Submission

Related Stories

Mysterious Star May Be Orbited by Alien Megastructures 71 comments

Beginning in 2009, the Kepler Space Telescope began looking at approximately 150,000 stars for signs of objects orbiting with some recognizable pattern in an attempt to find exo-planets. Now Ross Anderson writes in The Atlantic that scientists who search for extraterrestrial civilizations are scrambling to get a closer look at KIC 8462852, a star that undergoes irregularly shaped, aperiodic dips in flux down to below the 20% level that can last for between 5 and 80 days.

"We'd never seen anything like this star," says Tabetha Boyajian. "It was really weird. We thought it might be bad data or movement on the spacecraft, but everything checked out." Dips in the light emitted by stars are often shadows cast by transiting planets especially when they repeat, periodically, as you'd expect if they were caused by orbiting objects. Boyajian, a Yale Postdoc who oversees Planet Hunters, recently published a paper describing KIC 8462852's bizarre light pattern and explores a number of scenarios that might explain the pattern—instrument defects; the shrapnel from an asteroid belt pileup; an impact of planetary scale, like the one that created our moon.

SETI researchers have long suggested that we might be able to detect distant extraterrestrial civilizations, by looking for enormous technological artifacts orbiting other stars. Jason Wright says the unusual star's light pattern is consistent with a "swarm of megastructures," perhaps stellar-light collectors, technology designed to catch energy from the star. "When [Boyajian] showed me the data, I was fascinated by how crazy it looked," says Wright. "Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build." Boyajian is now working with Wright and Andrew Siemion on a proposal to point a massive radio dish at the unusual star, to see if it emits radio waves at frequencies associated with technological activity.

If they see a sizable amount of radio waves, they'll follow up with the Very Large Array (VLA) in New Mexico, which may be able to say whether the radio waves were emitted by a technological source, like those that waft out into the universe from Earth's network of radio stations. "In the meantime, Boyajian, Siemion, Wright, the citizen scientists, and the rest of us, will have to content ourselves with longing looks at the sky," says Anderson, "where maybe, just maybe, someone is looking back, and seeing the sun dim ever so slightly, every 365 days."


Original Submission

I’m STILL Not Sayin’ Aliens. but This Star is Really Weird. 54 comments

"The star KIC 8462852 (aka 'Tabby's Star') got a lot of press late last year because it was acting funny. It was undergoing a series of apparently random dips in brightness. Some of these dips were serious, with the amount of starlight dropping a staggering 22 percent.

That's a lot. It couldn't be a planet passing in front of the star, because the dips weren't periodic, and the amount of starlight blocked is different every time. Plus, even a planet as big as Jupiter (which is about as big as planets can get) would block less than one percent of the star's light at best.

[...] That left some speculation about, um, aliens. While it's incredibly unlikely, it does kinda fit what we're seeing.

[...] But still, the star is weird. We just found out it's even weirder than we thought.

Bradley Schaefer is an astronomer at Lousiana State University... [who] found that Tabby's Star has been photographed over 1,200 times as part of a repeated all-sky survey between the years 1890 – 1989.

What he found is rather astonishing: The star has been fading in brightness over that period, dropping by about 20 percent!

That's... bizarre. Tabby's Star is, by all appearances, a normal F-type star: hotter, slightly more massive, and bigger than our Sun. These stars basically just sit there and steadily turn hydrogen into helium. There have been times where the star has dimmed quite a bit, then brightened up again in the following years. On average, the star is fading about 16 percent per century, but that's hardly steady.

So it appears Tabby's Star dims and brightens again on all kinds of timescales: hours, days, weeks, even decades and centuries.

Again. That's bizarre. Nothing like this has ever been seen."

Above excerpted from Article: http://www.slate.com/blogs/bad_astronomy/2016/01/18/tabby_s_star_faded_substantially_over_past_century.html

They say it can't be caused by large dust cloud because they would see a known and detectable IR signature. So, aliens? Are they blinking at us in their 'morse code'? Building a hyperspace bypass? Got a better idea?

Schaefer's paper: KIC8462852 Faded at an Average Rate of 0.165±0.013 Magnitudes Per Century From 1890 To 1989 http://arxiv.org/pdf/1601.03256v1.pdf

F-type stars: https://en.wikipedia.org/wiki/F-type_main-sequence_star

Original about oddness in Oct 2015: http://www.slate.com/blogs/bad_astronomy/2015/10/14/weird_star_strange_dips_in_brightness_are_a_bit_baffling.html

FYI: The dimming is not caused by rapid rotation of star: https://twitter.com/Astro_Wright/status/689163586749333504


Original Submission

"Breakthrough Listen" to Search for Alien Radio Transmissions Near Tabby's Star 6 comments

UC Berkeley will use the Green Bank radio telescope to observe Tabby's Star (KIC 8462852) as part of the Breakthrough Listen initiative:

Breakthrough Listen, which was created last year with $100 million in funding over 10 years from the Breakthrough Prize Foundation and its founder, internet investor Yuri Milner, won't be the first to search for intelligent life around this star. "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," he said. "It's been looked at with Hubble, it's been looked at with Keck, it's been looked at in the infrared and radio and high energy, and every possible thing you can imagine, including a whole range of SETI experiments. Nothing has been found."

While Siemion and his colleagues are skeptical that the star's unique behavior is a sign of an advanced civilization, they can't not take a look. They've teamed up with UC Berkeley visiting astronomer Jason Wright and Tabetha Boyajian, the assistant professor of physics and astronomy at Louisiana State University for whom the star is named, to observe the star with state-of-the-art instruments the Breakthrough Listen team recently mounted on the 100-meter telescope. Wright is at the Center for Exoplanets and Habitable Worlds at Pennsylvania State University.

The observations are scheduled for eight hours per night for three nights over the next two months, starting Wednesday evening, Oct. 26. Siemion, Wright and Boyajian are traveling to the Green Bank Observatory in rural West Virginia to start the observations, and expect to gather around 1 petabyte of data over hundreds of millions of individual radio channels.

Also at BBC.

Previously:
Stephen Hawking and Yuri Milner Announce $100 Million "Breakthrough Listen" SETI Project
Mysterious Star May Be Orbited by Alien Megastructures
I'm STILL Not Sayin' Aliens. but This Star is Really Weird.


Original Submission

Non-Alien Explanation for Tabby's Star Dimming: It Ate a Planet 15 comments

Recently, some astronomers and others have excitedly pointed to Tabby's Star (KIC 8462852) as a possible example of alien megastructures causing a star to dim. A new study favors a more terrestrial explanation - a planetary collision with the star:

A new study set to be published Monday in the Monthly Notices of the Royal Astronomical Society suggests that smart aliens aren't responsible for KIC 8462852's dimming. Instead, the authors suggest, a planetary collision with Tabby's Star is to blame. This crash would explain not only why Tabby's Star has had wild fluctuations in brightness as of late, but why the star has been dimming gradually over the course of the last century.

It seems strange that a spectacular collision between a star and planet would cause a star to become dimmer, explains Ken Shen, a UC Berkeley astronomer and author on the study. But, says Shen, "the star has to eventually go back to being dimmer—the equilibrium state—the state that it was at before the collision."

KC 8462852's more recent and erratic dimming episodes, however, can be explained by a mess of debris moving around the star and absorbing its light, sometimes making it appear significantly dimmer to us Earthlings.

Previously:
Mysterious Star May Be Orbited by Alien Megastructures
I'm STILL Not Sayin' Aliens. but This Star is Really Weird.
"Breakthrough Listen" to Search for Alien Radio Transmissions Near Tabby's Star


Original Submission

Tabby's Star Dimming Could be Explained by a Saturn-Like Exoplanet 4 comments

Rather than debris or alien megastructures, Tabby's star may host a Saturn-like exoplanet:

The "alien megastructure" star that has been puzzling us for the past few years might have a more ordinary explanation: an orbiting Saturn-like planet, complete with wobbling rings. [...] Speculation abounded, with explanations ranging from exoplanetary comets to a vast orbiting "megastructure" built by an advanced alien civilisation.

Now Mario Sucerquia and his colleagues at the University of Antioquia in Colombia have proposed another possibility: a ringed planet, similar to Saturn, orbiting close to the star. Such a planet would dim the star's light in an irregular way during a transit.

First, the rings would block some of the star's light, followed by the planet, which would dim it further. Then, after the planet passes, the rings would block some light again. But because the rings would be at a different angle each time, the small dips at the beginning and end of the transits would be larger or smaller. Without seeing many transits, there would be no obvious pattern to this.

"Saturn-like" can mean a variety of things for the hypothetical object. For example, the rings of 1SWASP J1407b are about 200 times the diameter of the rings of Saturn.

Anomalous lightcurves of young tilted exorings

Related paper: KIC 8462852: Will the Trojans return in 2021?

Previously: Tabby's Star Under Observation After Dimming Event Detected


Original Submission

Dust the Likely Cause of Tabby's Star Dimming 11 comments

Tabby's star, aka KIC 8462852, is likely surrounded by orbiting dust grains that block ultraviolet light:

The bizarre long-term dimming of Tabby's star—also known as Boyajian's star, or, more formally, KIC 8462852—is likely caused by dust, not a giant network of solar panels or any other "megastructure" built by advanced aliens, a new study suggests.

Astronomers came to this conclusion after noticing that this dimming was more pronounced in ultraviolet (UV) than infrared light. Any object bigger than a dust grain would cause uniform dimming across all wavelengths, study team members said.

"This pretty much rules out the alien megastructure theory, as that could not explain the wavelength-dependent dimming," lead author Huan Meng of the University of Arizona said in a statement. "We suspect, instead, there is a cloud of dust orbiting the star with a roughly 700-day orbital period."

Aliens left to roam free once again.

Previously: Tabby's Star Under Observation After Dimming Event Detected
Tabby's Star Dimming Could be Explained by a Saturn-Like Exoplanet

Extinction and the Dimming of KIC 8462852 (DOI: 10.3847/1538-4357/aa899c) (DX) (arXiv)


Original Submission

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  • (Score: 0) by Anonymous Coward on Sunday May 21 2017, @04:36AM (1 child)

    by Anonymous Coward on Sunday May 21 2017, @04:36AM (#512880)

    The aliens have a human porn fetish.

  • (Score: 0) by Anonymous Coward on Sunday May 21 2017, @05:21AM (6 children)

    by Anonymous Coward on Sunday May 21 2017, @05:21AM (#512892)

    This would explain all those crazy stories in the bible, Bhagavad Gita, etc. They predicted it.

    • (Score: 0) by Anonymous Coward on Sunday May 21 2017, @06:54AM (3 children)

      by Anonymous Coward on Sunday May 21 2017, @06:54AM (#512913)

      Ancient aliens would be an explanation.

      However, a simpler explanation that also fits all the facts are humans who have either gone insane or are using any number of naturally occurring hallucinogenic drugs.

      When I was a kid, it was a common experience for religious people to hear voices in their heads. It was either an angel or their god commanding them to do something or another or alerting them to some danger. Unfortunately, humans like to use religion when they should be using mental health services.

      Occam's razor demands that we believe the simplest explanation that fits the facts.

      Once there are facts to demonstrate that it wasn't all just tall tales and hallucinations, then we can consider ancient aliens a bit more seriously.

      But whatever. Ancient aliens is a religion in its own right, complete with the usual signs of mental illness that go untreated because "muh religion!"

      • (Score: 0) by Anonymous Coward on Sunday May 21 2017, @07:02AM (2 children)

        by Anonymous Coward on Sunday May 21 2017, @07:02AM (#512915)

        I was making a sarcastic comment about how "aliens did it" is too vague an explanation to warrant more than a cursory "ok, maybe".

        • (Score: 0) by Anonymous Coward on Sunday May 21 2017, @09:29AM

          by Anonymous Coward on Sunday May 21 2017, @09:29AM (#512942)

          OK, maybe.

        • (Score: 0) by Anonymous Coward on Monday May 22 2017, @12:12AM

          by Anonymous Coward on Monday May 22 2017, @12:12AM (#513214)

          Oh, apologies. Here, borrow my sarcasm tags: <sarcasm> </sarcasm>. They're all yours!

    • (Score: 0) by Anonymous Coward on Sunday May 21 2017, @07:32AM (1 child)

      by Anonymous Coward on Sunday May 21 2017, @07:32AM (#512919)

      I see you're familiar with Erich von Däniken [wikipedia.org].

      • (Score: 2) by theluggage on Sunday May 21 2017, @12:41PM

        by theluggage (1797) on Sunday May 21 2017, @12:41PM (#512991)

        I see you're familiar with Erich von Däniken

        Who deserves immense request for two things:

        (1) Creating the textbook cautionary tale about the perils of confirmation bias.

        (2) His outstanding contribution to science fiction - if only he'd written his books as sci-fi instead of junk science... er, actually he'd probably have made less money.

        Although in the case of this Tabby's Star thing it's already been done at least twice ("Pandora's Star" and "A Deepness in the Sky").

  • (Score: 1) by khallow on Sunday May 21 2017, @05:26AM (4 children)

    by khallow (3766) Subscriber Badge on Sunday May 21 2017, @05:26AM (#512893) Journal

    One astronomer has proposed looking at the nearest 43 to 85 pulsars for megastructures

    While there might be some considerable value to a pulsar environment that I can't figure out, it would be a bad place for fleshy beings such as myself to hang out (though rad-hardened organisms might do just fine). On the other hand, the light is great for searching for car keys.

    • (Score: 2) by zocalo on Sunday May 21 2017, @10:49AM (3 children)

      by zocalo (302) on Sunday May 21 2017, @10:49AM (#512973)
      Actually, that could work out rather nicely. Pulsars are the remains of stars, so there would have been plenty of time for an advanced civilization to evolve before the star entered that stage of its life, which is a good start. Since the bulk of a pulsar's energy is emitted along a given axis, it might be possible to construct a Dyson structure with energy collection structures positioned along the axis of energy emission (the solar equator) and have the habitable / industrial areas of the structure at the solar poles. Whether the gravitational and radiation effects would be survivable at the necessary distances of the structure (both for the inhabitants and the structure itself), and how the inhabitants (or robotic ships) might transit the high-energy equatorial region for construction, maintenance work, etc. are likely to be problematic though.

      Still, you've got to wonder, given a civilization that is not only capable of engineering all of that but also surviving the transition of their star into a pulsar in the first place (a supernova, no less!), why they wouldn't have just figured out a way to relocate to another star system instead.
      --
      UNIX? They're not even circumcised! Savages!
      • (Score: 2) by zocalo on Sunday May 21 2017, @10:57AM (2 children)

        by zocalo (302) on Sunday May 21 2017, @10:57AM (#512975)
        Oops! Just realised that the energy of a pulsar is along the magnetic axis, e.g. slightly offset from the poles, not along the "equator" - I'd been thinking of the accretion disk of a black hole. That actually makes it easier (relatively speaking), as the habitat area around the star would be in a ring away from the bulk of the energy emission, while energy collection could be closer to the perimeter of the emission zone, but not so far in that it would be blasted out of existance.
        --
        UNIX? They're not even circumcised! Savages!
        • (Score: 1) by khallow on Sunday May 21 2017, @01:07PM (1 child)

          by khallow (3766) Subscriber Badge on Sunday May 21 2017, @01:07PM (#513001) Journal
          I bet the magnetic pole moves around and might even cross the rotational equator of the pulsar on a repetitive basis. It seems a challenging environment to say the least.
          • (Score: 2) by zocalo on Sunday May 21 2017, @03:02PM

            by zocalo (302) on Sunday May 21 2017, @03:02PM (#513032)
            Probably, but perhaps not by all that much. My impression is that a star's magnetic axis is pretty similar to a planet's like our own - it wobbles around and might even flip from time to time, but generally stays within a given zone. Given that a pulsar has such a high spin rate, so perhaps it's something like a gyroscope - the faster the rotation the more stable the axis is, and the less likely the magnetic poles are to move around? Alternatively, if any such changes don't occur on a short timescale, perhaps it would be possible for its creators to re-align a Dyson construct with the shifting poles as required, assuming a swarm, rather than a solid object, then they might even be able to get away with just re-aligning the energy collecting components.
            --
            UNIX? They're not even circumcised! Savages!
  • (Score: 0) by Anonymous Coward on Sunday May 21 2017, @05:38AM (3 children)

    by Anonymous Coward on Sunday May 21 2017, @05:38AM (#512897)

    How old is this star? Is it on the main sequence? Seems like and important detail...

  • (Score: 0) by Anonymous Coward on Sunday May 21 2017, @12:38PM (2 children)

    by Anonymous Coward on Sunday May 21 2017, @12:38PM (#512990)

    Obviously, what we are seeing is due to pilot error: Their massive space ships weaving back and forth along the intended heading of a straight line between their star and ours. The dimming will increase in frequency and magnitude until we realize the invasion is imminent and too late for us to escape or defend ourselves.

    • (Score: 0) by Anonymous Coward on Sunday May 21 2017, @02:14PM (1 child)

      by Anonymous Coward on Sunday May 21 2017, @02:14PM (#513019)

      Can't be any worse than our current overloads.

      • (Score: 0) by Anonymous Coward on Sunday May 21 2017, @05:20PM

        by Anonymous Coward on Sunday May 21 2017, @05:20PM (#513071)

        Can't be any worse than our current overloads.

        That's a shocking statement.

  • (Score: 2) by kaszz on Sunday May 21 2017, @04:24PM (1 child)

    by kaszz (4211) on Sunday May 21 2017, @04:24PM (#513049) Journal

    Could it be a interplanetary cloud that causes the dimming?

    They can be random and do partial dimming thus fitting the description.

    • (Score: 2) by deimtee on Monday May 22 2017, @01:52AM

      by deimtee (3272) on Monday May 22 2017, @01:52AM (#513254) Journal

      Not interplanetary dust because the infrared would be detectable.
      Not interstellar dust because other stars along the same/similars sightlines are not showing any dimming or brightening.

      The reason it has all the astronomers worked up is that it doesn't fit any easy answers.

      --
      If you cough while drinking cheap red wine it really cleans out your sinuses.
  • (Score: 0) by Anonymous Coward on Monday May 22 2017, @05:12PM

    by Anonymous Coward on Monday May 22 2017, @05:12PM (#513597)

    is this like Supertitanium scaffolding around their star so they can repair the Reflecto Tiles?

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