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posted by martyb on Sunday January 15 2017, @02:09PM   Printer-friendly
from the Burrrrrp! dept.

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

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

Tabby's Star Under Observation After Dimming Event Detected 24 comments

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

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  • (Score: 3, Funny) by Anonymous Coward on Sunday January 15 2017, @02:26PM

    by Anonymous Coward on Sunday January 15 2017, @02:26PM (#454083)

    Now the aliens are throwing planets into star, we really need to get on this, they seem hostile!

    • (Score: 2) by zocalo on Sunday January 15 2017, @05:17PM

      by zocalo (302) on Sunday January 15 2017, @05:17PM (#454120)
      I suppose that's one way to qualify as a Kardashev type 1 civilization, although using an entire planet as a battery does seem a rather environmentally unfriendly and non-renewable way of recovering 100% of the energy the planet received from its star... Peak Oil has nothing on Peak Planet...
      --
      UNIX? They're not even circumcised! Savages!
    • (Score: 2) by theluggage on Sunday January 15 2017, @09:51PM

      by theluggage (1797) on Sunday January 15 2017, @09:51PM (#454175)

      ...it only scored 30 points.

  • (Score: 0) by Anonymous Coward on Sunday January 15 2017, @02:49PM

    by Anonymous Coward on Sunday January 15 2017, @02:49PM (#454087)

    Nom nom nom!

  • (Score: 0) by Anonymous Coward on Sunday January 15 2017, @04:50PM

    by Anonymous Coward on Sunday January 15 2017, @04:50PM (#454113)

    They tossed a couple of planets in as they needed the extra output for their solar sails, to get to earth, to eat us.

    Either that, or they tried an old timelord trick of tossing a black hole into one, so they can talk to their friends in another dimension. And it may not have gone well.

  • (Score: 3, Informative) by Runaway1956 on Sunday January 15 2017, @05:15PM

    by Runaway1956 (2926) Subscriber Badge on Sunday January 15 2017, @05:15PM (#454119) Journal

    I've been messing with people's minds by turning the rheostat up and down randomly. I bought it at a yard sale, brought it home, and found Tesla's name scratched into the back side of it. It's almost like magic - science so advanced that I can't understand it!

    • (Score: 0) by Anonymous Coward on Sunday January 15 2017, @07:36PM

      by Anonymous Coward on Sunday January 15 2017, @07:36PM (#454137)

      Did you reply to the wrong thread? Cause it sure looks that way... However it would be so hilarious if aliens put such effort into screwing with humans :)

      • (Score: 2) by Runaway1956 on Sunday January 15 2017, @07:50PM

        by Runaway1956 (2926) Subscriber Badge on Sunday January 15 2017, @07:50PM (#454149) Journal

        Maybe this was the wrong thread. I was responding to a thread discussing why a star grows brighter and dimmer. And, the explanation is, my rheostat. Or, Tesla's rheostat, which came to be in my possession, much as most dead people's property ends up in other people's possession. Watch this - I turn it to the right, the star gets brighter - I turn it left, the star grows dimmer. I don't know what happens if I push the button above the dial, want me to try?

  • (Score: 2) by Sulla on Sunday January 15 2017, @06:07PM

    by Sulla (5173) on Sunday January 15 2017, @06:07PM (#454124) Journal

    Why is it so hard to just let it stand? Far better for the species to be forced to accept that there is another species out there vastly ahead of us. By pushing in popular culture would be an easy catylist to trigger thsat competitive spirit in man and get that space race going again. But I guess far easier to do as much as possible to prove we are alone in the universe and keep us fighting over petty shit here on Earth.

    https://archive.org/details/XMinus1_A [archive.org]
    See #37 - The Cave of Night

    --
    Ceterum censeo Sinae esse delendam
    • (Score: 3, Interesting) by takyon on Sunday January 15 2017, @07:44PM

      by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Sunday January 15 2017, @07:44PM (#454146) Journal

      Your fear will be warranted if the James Webb Space Telescope and a couple of other upcoming missions find nothing. Especially if we launch ATLAST [wikipedia.org] and find nothing. These missions would be imaging exoplanets and possibly finding evidence of vegetation.

      Is the situation so dire that we can't wait another 5-10 years to get it right? I doubt it.

      --
      [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
      • (Score: 3, Interesting) by Sulla on Sunday January 15 2017, @07:53PM

        by Sulla (5173) on Sunday January 15 2017, @07:53PM (#454152) Journal

        I wonder how many times a similar thing can be said. Will be nice to be able to tell my kids in 15 years that they just need to wait a bit longer, just as my dad assured me a decade ago that we were right on the edge and my grandfather told him that it wouldnt be long either.

        Fortunately we seem to be seeing some actual progress for the first time in a long time, but I am sure that means a lot to a kid growing up listening to radio SF who wont live long enough to see it.

        --
        Ceterum censeo Sinae esse delendam
  • (Score: 4, Insightful) by gman003 on Sunday January 15 2017, @11:26PM

    by gman003 (4155) on Sunday January 15 2017, @11:26PM (#454196)

    The reporting on this story has been generally atrocious, because apparently reporters never learn probability theory.

    The "alien megastructure" hypothesis came from Dr. Jason Wright, who was doing theoretical studies on what we would expect to see if there was an alien megastructure around a star. The data we have on KIC 8462852 was not inconsistent* with an alien megastructure, but every scientist - even Dr. Wright - considered that the least likely explanation. At the same time, though, KIC 8462852 is the best current candidate for an alien megastructure, because all other stars are either unstudied or are inconsistent with that hypothesis.

    Apparently very few reporters were able to distinguish "out of all the stars we have examined, KIC 8462852 has the highest probability of being an alien megastructure" from "out of all the hypotheses for KIC 8462852, an alien megastructure is the least probable". The reporting I saw usually represented the story as "this scientist says it's probably aliens, other scientists disagree", with the better sources giving it as "this scientist says it could be aliens, others disagree", which still isn't quite right, and the worse sources saying "we found aliens!", which is almost completely wrong.

    This kind of thing seems to happen a lot with reporting on low-probability unknown or future events. Reporters seem to have a knee-jerk "both sides of the story" reflex that turns every story into a conflict, even when it isn't. They also rarely show any grasp of probability - if it's describe by experts as "most likely", it's treated as being completely true, while everything else is either as good as false, or as being a fringe theory (which some people, bizarrely, treat as more true, but that's an entirely different problem).

    * I've been using the "not inconsistent" phrasing for stuff like this (where the data and/or hypothesis is weak) because it more explicitly leaves open the possibility that future data will be inconsistent, or that other hypotheses are also consistent with the data. If you just say "the data is consistent with this hypothesis", almost everyone seems to interpret it as "the data proves this hypothesis right".

    • (Score: 0) by Anonymous Coward on Monday January 16 2017, @12:33AM

      by Anonymous Coward on Monday January 16 2017, @12:33AM (#454206)

      or as being a fringe theory (which some people, bizarrely, treat as more true, but that's an entirely different problem).

      Oh, hell, you see that ALL the time here. Especially if it has anything to do with the "Evil Government".

    • (Score: 2) by esperto123 on Monday January 16 2017, @09:57AM

      by esperto123 (4303) on Monday January 16 2017, @09:57AM (#454326)

      Agreed it was a far fetched and every astronomer under the sun regarded as a very very low probability, but it was fun to speculate about.
      The idea that we might have seen evidence of a far more advanced life for is fascinating to the point of irresistible, but although some nut jobs took it seriously, most knew it was most likely a natural phenomenon, and use it to have some fun.