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from the they-are-just-constructing-a-Dyson-sphere dept.
"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
(Score: 1) by an Anonymous Coward on Wednesday January 20 2016, @05:24PM
Personally, I'm curious if this star's apparent brightness would be consistent between observatories located in different portions of our star system. The behavior makes me think of an object in between us and the star, but much further out than a planet, maybe even closer to us. As for the randomness: Irregular shape? Relatively small size/mass? Gravitational anomalies?
(Score: 2) by Bobs on Wednesday January 20 2016, @05:43PM
The behavior makes me think of an object in between us and the star, but much further out than a planet,...
Interesting idea, but if this were the case then either
1) the blocking object was close to Sol: then it would be dimming more than one star, particularly over long periods of time, or
2) the blocking object is close to KIC8462852: then it would have to be amazingly and uniquely massive to intermittently block for a century plus. Our solar systems have moved a bit since we first started taking pictures of it.
(Score: 4, Interesting) by VLM on Wednesday January 20 2016, @06:57PM
the blocking object was close to Sol: then it would be dimming more than one star, particularly over long periods of time, or
It would make a good lovecraftian horror type story to have the aliens so pissed off we're here, that they build and maintain a shield thing between us and them.
Imagine an infinite power civilization, maybe they write a self replicating virus that once unleashed spreads to all stars for X lightyears then builds and maintains a little shield between every star and the home world. It might even provide an interesting filtering effect, that once a culture is of a high enough cultural and technological level to mostly see around the shield, they don't feel so scared anymore, for better or worse.
Or maybe a 3rd party is hoping we're not going to get scared. Or that star is the interstellar empire equivalent of area 51 and they're going to be all bent out of shape that we're observing.
I'm not claiming this is true, but it would make an interesting sci fi novel plot.
(Score: 3, Interesting) by Webweasel on Thursday January 21 2016, @03:26PM
Greg Egan: Quarantine
ISBN-10: 0575081724
ISBN-13: 978-0575081727
It's more based on the multi universe quantum theory, but as part of the plotline the whole "quantum events must be observed" is played on.
The rest of the universe is populated by quantum beings and humanity causes mass genocide by collapsing the events when looking out and observing the universe.
As a result, there is a sphere around our solar system to stop us observing the real universe and killing everything!
Priyom.org Number stations, Russian Military radio. "You are a bad, bad man. Do you have any other virtues?"-Runaway1956
(Score: 0) by Anonymous Coward on Wednesday January 20 2016, @07:03PM
Alternatively it could simply be the first evidence of an orphan planet somewhere in between. Some models predict dozens of planets forming per star with unstable orbits and flung out to wander the darkness alone and difficult to detect.
(Score: 1) by an Anonymous Coward on Thursday January 21 2016, @01:07AM
I was going to mention the relative velocities involved in regards to the overall decline in apparent brightness. But, I was pressed for time and it was removed in the interest of brevity.
Looking at the data in the first article, the sudden dimming events seem to occur just shy of two years apart, which might be noteworthy. What if a relatively small object was located just so, so that it eclipsed that star at a particular point in our orbit, but not always since our path actually wobbles slightly due the effects of bodies other than the earth and sun. But, how would that account for the overall dimming?
For the overall dimming issue, there is also the possibility of a light emitting object beyond and partially eclipsed by the star in question. But, wouldn't the spectral line leave very obvious traces of two different star pattens, with one fading in and out with the variations in luminosity? The post mentions that they already ruled out a debris cloud by looking for unexplained IR output. I would assume the emission pattern in such a case would have been noticed long ago. It also would not explain the sudden dips.
The talk of aliens has an inverted version of "sometimes the light at the end of a tunnel is a train" rolling around in the back of my mind.