Text "Between these constellations sits an unusual star, invisible to the naked eye, but visible to the Kepler Space Telescope, which stared at it for more than four years, beginning in 2009. “We’d never seen anything like this star,” says Tabetha Boyajian, a postdoc at Yale. “It was really weird. We thought it might be bad data or movement on the spacecraft, but everything checked out.” Kepler was looking for tiny dips in the light emitted by this star. Indeed, it was looking for these dips in more than 150,000 stars, simultaneously, because these dips are often shadows cast by transiting planets. Especially when they repeat, periodically, as you’d expect if they were caused by orbiting objects. The Kepler Space Telescope collected a great deal of light from all of those stars it watched. So much light that Kepler’s science team couldn’t process it all with algorithms. They needed the human eye, and human cognition, which remains unsurpassed in certain sorts of pattern recognition. Kepler’s astronomers decided to found Planet Hunters, a program that asked “citizen scientists” to examine light patterns emitted by the stars, from the comfort of their own homes. In 2011, several citizen scientists flagged one particular star as “interesting” and “bizarre.” The star was emitting a light pattern that looked stranger than any of the others Kepler was watching. The light pattern suggests there is a big mess of matter circling the star, in tight formation. That would be expected if the star were young. When our solar system first formed, four and a half billion years ago, a messy disk of dust and debris surrounded the sun, before gravity organized it into planets, and rings of rock and ice. But this unusual star isn’t young. If it were young, it would be surrounded by dust that would give off extra infrared light. There doesn’t seem to be an excess of infrared light around this star."
Text "It appears to be mature. And yet, there is this mess of objects circling it. A mess big enough to block a substantial number of photons that would have otherwise beamed into the tube of the Kepler Space Telescope. If blind nature deposited this mess around the star, it must have done so recently. Otherwise, it would be gone by now. Gravity would have consolidated it, or it would have been sucked into the star and swallowed, after a brief fiery splash. Boyajian, the Yale Postdoc who oversees Planet Hunters, recently published a paper describing the star’s bizarre light pattern. Several of the citizen scientists are named as co-authors. The paper 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. The paper finds each explanation wanting, save for one. If another star had passed through the unusual star’s system, it could have yanked a sea of comets inward. Provided there were enough of them, the comets could have made the dimming pattern. But that would be an extraordinary coincidence, if that happened so recently, only a few millennia before humans developed the tech to loft a telescope into space. That’s a narrow band of time, cosmically speaking. And yet, the explanation has to be rare or coincidental. After all, this light pattern doesn’t show up anywhere else, across 150,000 stars. We know that something strange is going on out there."
NASA's Kepler Space Telescope is tasked with finding small, rocky worlds orbiting distant stars. However, exoplanets aren't the only thing Kepler can detect — stellar flares, star spots and dusty planetary rings can also pop up in the mission's observations.
But there's also been speculation that Kepler may have the ability to detect more than natural phenomena; if they're out there, Kepler may also detect the signature of artificial structures orbiting other stars. Imagine an advanced civilization that's well up on the Kardashev scale and has the ability to harness energy directly from its star. This hypothetical alien civilization may want to construct vast megastructures, like supersized solar arrays in orbit around their host star, that could be so big that they blot out a sizable fraction of starlight as they pass in front.
When Kepler detects an exoplanet, it does so by sensing the very slight dip in starlight from a given star. The premise is simple: An exoplanet orbits in front of star (known as a "transit"), Kepler detects a slight dimming of starlight and creates a "lightcurve" — basically a graph charting the dip in starlight over time. Much information can be gleaned from the lightcurve, such as the physical size of the transiting exoplanet. But it can also deduce the exoplanet's shape.
By surrounding their star with swarms of energy-collecting satellites, advanced civilizations could create Dyson spheres. See full infographic Credit: by Karl Tate, Infographics Artist
Normally the shape of an exoplanet isn't particularly surprising because it's, well, planet-shaped. It's round. The physics of planetary formation dictate that a planetary body above a certain mass will be governed by hydrostatic equilibrium. But say if Kepler detects something that isn't round. Well, that's when things can get a bit weird.
For the most part, any dip in star brightness can be attributed to some kind of natural phenomenon. But what if all possibilities are accounted for and only one scenario is left? What if that scenario is — this object appears to be artificial? In other words, what if it's alien?
In a chilling article written by Ross Andersen of The Atlantic, at first glance, it seems we may be at this incredible juncture.
A star, named KIC 8462852, has been found with a highly curious transit signal. In a paper submitted to the journal Monthly Notices of the Royal Astronomical Society, astronomers, including citizen scientists from the Planet Hunters crowdsourcing program, report: "Over the duration of the Kepler mission, KIC 8462852 was observed to undergo irregularly shaped, aperiodic dips in flux down to below the 20 percent level."
The research paper is thorough, describing the phenomenon, pointing out that this star is unique — we've seen nothing like it. Kepler has collected data on this star steadily for four years. It's not instrumental error. Kepler isn't seeing things; the signal is real.
"We'd never seen anything like this star," Tabetha Boyajian, a postdoctorate researcher at Yale University and lead author, told The Atlantic. "It was really weird. We thought it might be bad data or movement on the spacecraft, but everything checked out."
The Planet Hunters volunteers are depended on to seek out transits in Kepler's stars in the direction of the constellation Cygnus. This is a huge quantity of data, from over 150,000 stars in Kepler's original field of view, and you can’t beat the human eye when identifying a true dip in starlight brightness. The Planet Hunters described KIC 8462852 as "bizarre," "interesting" and a "giant transit." They’re not wrong.
Follow-up studies focus on two interesting transit events at KIC 8462852, one that was detected between days 788 and 795 of the Kepler mission and between days 1510 to 1570. The researchers have tagged these events as D800 and D1500 respectively.
The D800 event appears to have been a single transit causing a star brightness drop-off of 15 percent, whereas D1500 was a burst of several transits, possibly indicating a clump of different objects, forcing a brightness dip of up to 22 percent. To cause such dips in brightness, these transiting objects must be huge.
The researchers worked through every known possibility, but each solution presented a new problem. For example, they investigated the possibility of some kind of circumstellar disk of dust. However, after looking for the infrared signal associated with these disks, no such signal could be seen.
Also, the star is a mature F-type star, approximately 1.5 times the size of our sun. Circumstellar disks are usually found around young stars.
The researchers also investigated the possibility of a huge planetary collision: could the debris from this smashup be creating this strange signal? The likelihood of us seeing a planetary collision is extremely low. There is no evidence in data taken by NASA's Wide-field Infrared Survey Explorer (WISE) that a collision happened, creating a very tiny window of opportunity between WISE’s mission end and the beginning of Kepler's mission (of a few years) for an astronomically unlikely cosmic event like this to occur.
The only natural explanation favored by the researchers seems to focus on an intervening clump of exocomets.
"One way we imagine such a barrage of comets could be triggered is by the passage of a field star through the system," write the researchers.
Indeed, they argue, there’s a nearby star that might have tidally disturbed otherwise dormant comets in the outermost regions of the KIC 8462852 star system. This small star is located around 1,000 AU from KIC 8462852 and whether it’s a binary partner or an interstellar visitor, its presence may have caused some cometary turmoil. Like the other scenarios, however, the exocomet explanation still falls short of being fully satisfactory.
This research paper focuses only on natural and known possible causes of the mystery transit events around KIC 8462852. A second paper is currently being drafted to investigate a completely different transit scenario that focuses around the possibility of a mega-engineering project created by an advanced alien civilization. This may sound like science fiction, but our galaxy has existed for over 13 billion years, it’s not such a stretch of the imagination to think that an alien civilization may be out there and evolved to the point where they can build megastructures around stars.
"Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build," Jason Wright, an astronomer from Penn State University, told The Atlantic.
Indeed, hunting down huge structures that obscure the light from stars is no new thing. The Search for Extraterrestrial Technology (SETT) is one such project that does just this. Only recently, a survey of the local universe focused on the hope of detecting the waste heat generated by a technologically advanced civilization, specifically a Type II Kardashev civilization.
On the Kardashev scale, a Type II civilization has the ability to utilize all the available energy radiating from a star. Using a vast shell or series of rings surrounding a star, a Dyson spherelike structure may be constructed. This has the effect of blotting out the star from view in visible wavelengths, but once the solar energy has been used by the alien civilization, the energy is shifted to longer wavelengths and likely lost as infrared radiation. This recent search for aliens’ waste heat drew a blank, reaching the conclusion that as there appears to be no alien intelligence cocooning stars to harvest their heat, there’s likely no Type II civilization nearby.
But as KIC 8462852 is showing us, there may be something else out there — possibly an alien intelligence that is well on its way to becoming a Type II civilization, which is setting up some kind of artificial structure around its star.
Of course, these mystery transit events are nowhere near "proof" of an alien civilization. In fact, it's barely evidence and a lot more work needs to be done.
The next step is to point a radio antenna at KIC 8462852, just to see whether the system is generating any artificial radio signals that could indicate the presence of something we'd define as "intelligent." Boyajian and Wright have now teamed up with Andrew Siemion, the Director of the SETI Research Center at the University of California, Berkeley, to get a radio telescope to listen into the star and if they detect an artificial signal, they will request time on the Very Large Array (VLA) to deduce whether any radio signals from that star are the chatter of an alien civilization. It might be a long shot, and the phenomenon is more likely a clump of comets or some other natural phenomenon that we haven’t accounted for blocking star light from view, but it’s worth investigating, especially if there really is some kind of alien intelligence building structures, or perhaps, ancient structures of a civilization long-gone, around a star only 1,500 light-years away from Earth.
Search For Intelligent Aliens Near Bizarre Dimming Star Has Begun
by Mike Wall, Space.com Senior Writer October 19, 2015
The search for signs of life in a mysterious star system hypothesized to potentially harbor an "alien megastructure" is now underway.
Astronomers have begun using the Allen Telescope Array (ATA), a system of radio dishes about 300 miles (483 kilometers) northeast of San Francisco, to hunt for signals coming from the vicinity of KIC 8462852, a star that lies 1,500 light-years from Earth.
NASA's Kepler space telescope found that KIC 8462852 dimmed oddly and dramatically several times over the past few years. The dimming events were far too substantial to be caused by a planet crossing the star's face, researchers say, and other possible explanations, such as an enormous dust cloud, don't add up, either.
The leading hypothesis at the moment involves a swarm of comets that may have been sent careening toward KIC 8462852, possibly after a gravitational jostle by a passing star. But it's also possible, astronomers say, that the signal Kepler saw was caused by huge structures built by an alien civilization — say, a giant assortment of orbiting solar panels.
That latter possibility, remote though it may be, has put KIC 8462852 in the crosshairs of scientists who hunt for signals that may have been generated by intelligent aliens.
"We are looking at it with the Allen Telescope Array," said Seth Shostak, a senior astronomer at the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, California.
"No problem with that; I think we ought to, for sure," Shostak told Space.com. But, he added, people "should perhaps moderate their enthusiasm with the lessons of history."
Shostak cited the example of pulsars, fast-spinning, superdense stellar corpses that emit beams of high-energy radiation. These beams are picked up by instruments on and around Earth as regular pulses, because they can only be detected when they're fired straight at the planet (an event that occurs at predictable intervals because of pulsars' rotation).
Astronomers know all this now. But in the 1960s, when the first pulsar signals were discovered, some scientists interpreted them as possible alien transmissions.
"So history suggests we're going to find an explanation for this that doesn't involve Klingons, if you will," Shostak said of the KIC 8462852 mystery.
But until such an explanation is found, the intelligent-aliens hypothesis will still be on the table, even if the ATA and other instruments like it come up empty. The lack of a detectable signal, after all, does not establish that KIC 8462852 is a lifeless system.
The star may support lifeforms that do not emit signals we can pick up, for example. Or it may once have hosted a civilization that has since gone extinct, leaving the strange megastructure as a sort of monument.
Kepler's main planet-hunting work suggests that the Milky Way galaxy teems with billions of rocky, potentially habitable planets. So KIC 8462852 is far from the only lead that Shostak and his colleagues will be chasing down in the coming years.
"It almost doesn’t matter where you point your telescope, because there are planets everywhere," Shostak said. "If there's somebody out there, there are going to be so many of them out there that I do think there's a chance."
If alien civilizations are broadcasting from around a strangely behaving star, they aren't chatting loud enough for humans to hear them from Earth, new observations show.
The star KIC 8462852 garnered popular attention in October, when scientists announced that it showed evidence of periodically dimming by 20 percent or more, which some people theorized could be caused by the shadow of an alien megastructure. However, observations of KIC 8462852 by researchers at the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, California, have so far picked up no radio signals that could indicate extraterrestrial chatter.
"The history of astronomy tells us that, every time we thought we had found a phenomenon due to the activities of extraterrestrials, we were wrong," SETI Institute astronomer Seth Shostak said in a statement. "But although it's quite likely that this star's strange behavior is due to nature, not aliens, it's only prudent to check things out." [13 Ways to Hunt Intelligent Alien Life]
"No clear evidence"
The Kepler Space Telescope searches for planets around distant stars by looking for drops in the stars' brightness that could have been created when orbitng planets pass in front of them. Observations of KIC 8462852 showed that it was dimming in a very peculiar way — not the smooth, regular dimming that would be created by a planet. (This unexplainable behavior has earned the star the colloquial nickname the "WTF" star, which stands for "What the Flux.")
Several natural explanations were proposed, including the presence of a swarm of comets orbiting the star, which lies about 1,400 light-years from Earth. What seized the public imagination, however, was the idea that the Kepler-studied star may host a swarm of alien megastructures in orbit, built by technologically advanced civilizations.
With this possibility in mind, the SETI Institute turned the Allen Telescope Array (ATA) on the star, studying it for more than two weeks. The ATA's dishes examined the star for two types of radio signals. Narrowband signals, which make up most SETI searches, are considered plausible for advanced societies to use as a "hailing signal" to announce their presence to other civilizations. Broadband signals might come from spacecraft servicing any alien projects around the star, and could leak from spacecraft propelled by intense microwave beams.
That bizarre-looking star just got a lot weirder, and yes — it could be aliens
By Jessica Orwig 3 hours ago Business Insider
Three months ago, news broke that a giant "alien megastructure" could exist around a bizarre-looking star 1,500 light years away.
While the prospect of aliens was first launched by Penn State astronomer Jason Wright, almost everyone in the astronomy community agreed that the chances that this was the case were "very low."
Now, the latest investigations into this strange star by Louisiana State University astronomer Bradley Schaefer have re-ignited the alien theory, New Scientist reported.
What makes this star, called KIC8462852, so bizarre is the drastic changes in light we see from it over time. Many stars experience temporary fluctuations in brightness, increasing and decreasing in luminosity over time, but KIC8462852's changes are severe by comparison.
Between 2009 and 2013, astronomers using the Kepler space telescope discovered that it would sometimes lose up to 20% of its brightness. What's more, the changes didn't follow any obvious pattern.
That would suggest something gigantic must be blocking the light at random times, meaning it couldn't be a planet or other regular orbiting object because that would generate a distinct pattern of dimming light. It must be something that changes shape over time, thereby blocking different levels of light at random intervals. Surprise: It's probably not comets An alien megastructure, called a Dyson sphere, was suggested as one explanation for what scientists have observed, but the most likely reason astronomers came up with was comets — a giant family of them.
But Shaefer says not so fast.
“The comet-family idea was reasonably put forth as the best of the proposals, even while acknowledging that they all were a poor lot,” Schaefer told New Scientist. “But now we have a refutation of the idea, and indeed, of all published ideas.”
To make his discovery, Schaefer had to dig deep down into the astronomy archives at Harvard. It turns out, astronomers have data on KIC8462852 dating back as far as 1890.
By analyzing over 1,200 measurements of this star's brightness taken from 1890 through 1989, Schaefer found that the irregular dimming of KIC8462852 has been going on for over 100 years. Schaefer published his findings in the online pre-print server arxiv.org.
What's more, he explains in his paper that this "century-long dimming trend requires an estimated 648,000 giant comets (each with 200 km diameter) all orchestrated to pass in front of the star within the last century," which he said is "completely implausible."
So what is it? By killing the comet-theory, Schaefer has brought us one step closer to finding out what is really happening around KIC8462852.
At the same time, he's also reignited the possibility that the source could be an alien megastructure that an advanced alien civilization has been slowly building over time. One thing's certain for Schaefer: The bizarre dimmings are probably caused by a single, physical mechanism that's undergoing some type of ongoing change.
"The century-long dimming and the day-long dips are both just extreme ends of a spectrum of timescales for unique dimming events, so by Ockham's Razor, all this is produced by one physical mechanism," Shaefer stated in his paper. "This one mechanism does not appear as any isolated catastrophic event in the last century, but rather must be some ongoing process with continuous effects."
Schaifer isn't the only one interested in learning more about KIC8462852. Late last year, astronomer Doug Vakoch and his team at the new organization called SETI (Search for Extraterrestrial Intelligence) International — not to be confused with the SETI Institute — went hunting for aliens around KIC8462852.
They searched for signals that an alien civilization might be beaming toward Earth either in radio or visible wavelengths, but ultimately they came up empty handed. So, if it is aliens, then they're being awfully quiet.
How Astronomers Will Solve the 'Alien Megastructure' Mystery
Maddie Stone Today 9:00am
KIC 8462852 has quickly become one of the biggest astronomical mysteries of the decade. It’ll be months before we have any firm answers on this fitfully flickering star, but astronomers intend to get to the bottom of it. How?
“If we could catch it in the act of dimming again, that would really help,” Penn State’s Jason Wright told Gizmodo.
Wright’s the astronomer who made KIC 8462852 famous last fall, when he nonchalantly suggested that the star might be occluded by an alien megastructure. He, along with several other astronomers I spoke with this week, agrees that the way we’re going to figure this weird star out is to watch it doing something weird.
KIC 8462852, also known as “Tabby’s Star,” was first spotted in the Kepler Space Telescope’s dataset last September. Despite being an ordinary, main sequence F-type star—slightly hotter and larger than our sun—it caught astronomers’ attention. Over four years of observational data, the star’s light output intermittently tanked, something that isn’t consistent with any astronomical phenomenon we’re aware of. Explanations for the star’s unruly behavior ranged from a swarm of comets to gravity darkening to alien megastructures. You can imagine which of those possibilities sparked a global hysteria.
But KIC 8462852 wasn’t done surprising us. The mystery deepened last week when Louisiana State University’s Bradley Schaefer decided to look at KIC 8462852 in old photographic plates of the sky. When he did, he saw something astonishing: over the past century, the star’s total light output has dropped by about 19 percent. This star isn’t just sputtering—it’s fading out entirely.
“Observationally, there is zero precedent for any main sequence star to vary in brightness like this,” Schaefer told Gizmodo. “Seeing this star fade by 20 percent over a century is more than just startling.”
“We were baffled when it was just the Kepler data, and if it were just this we’d be baffled,” Wright said. “The comet hypothesis was great because it could explain almost anything, but it doesn’t really work for the new data.”
What we do know, according to Wright, is that whatever’s occluding the star isn’t emitting strongly in the infrared spectrum, meaning it isn’t very warm. That means we’re talking about something in a distant orbit, which doesn’t improve our odds of getting a good look at it.
But there is one way astronomers can learn what’s causing the star to sputter—and that’s to catch KIC 8462852 doing it again.
When Kepler watched KIC 8462852 flicker several years back, it was only collecting white light—aggregating information across the visible spectrum. All we can do with this data is pinpoint dimming events. But if it happened again, astronomers would be prepared to make precise measurements in a broader range of wavelengths. As KIC 8462852's starlight passes through whatever material is occluding it, certain colors will be absorbed more than others. This gives us a spectral fingerprint, which can be used to work out what type of material we’re looking at.
“From the spectrum, we might see absorption lines from any gas associated with the ‘occulter,’” Shaefer said. “We might see a reddening that would point to the occulter being mainly dust, or we might see a color neutral dip that would point to a solid body. This would greatly narrow down models.”
For the next few months, astronomers are sitting tight. KIC 8462852 is behind the Sun and only visible during daylight hours, making it impossible to observe from the ground. According to Tabetha Boyajian, the Yale astronomer who discovered the star, a few satellites are monitoring it, but the temporal coverage isn’t great. “Mainly, we are now using this time to prepare for what to do when the star becomes visible again in a few months,” she said.
This includes discussing different scenarios, and figuring out what data will be needed to confirm or refute each of them. “When the dipping begins again, we will be prepared to hit it with everything we have,” she said.
Wright added that although two independent surveys haven’t turned up any evidence of extraterrestrial technology, UC Berkeley’s SETI program is now working with the billionaire-backed alien hunting initiative Breakthrough Listen, and plans to conduct a very sensitive broadband sweep of the star’s neighborhood in the next few months. The prospect that we’re looking at a bona fide Dyson sphere is as unlikely as ever, but....well, it hasn’t been ruled out.
“The ET hypothesis has very little predicative power,” Wright said, noting that you can invoke it to explain just about anything—the so-called “aliens in the gaps” fallacy.
Nevertheless, you can bet astronomers won’t rest until they’re sure one way or the other.
Comets May Not Explain 'Alien Megastructure' Star's Strange Flickering After All
By Shannon Hall, Space.com Contributor February 3, 2016
It's looking less likely that a swarm of comets or an "alien megastructure" can explain a faraway star's strange dimming.
The star (nicknamed "Tabby's Star," after its discoverer, Tabetha Boyajian) made major headlines last October when Jason Wright, an astronomer at Pennsylvania State University, suggested that it could be surrounded by some type of alien megastructure. A more likely idea — one that's far less exciting — is that the star is orbited by a swarm of comets. But scientists can't be sure either way.
Now, Bradley Schaefer, an astronomer at Louisiana State University, has probed the star's behavior over the past century by looking at old photographic plates. Not only does the star's random dipping date back more than a century, but it also has been gradually dimming over that period — a second constraint that makes it even harder to explain.
The first signs of the star's oddity came from NASA's planet-hunting Kepler space telescope, which continually monitored the star (as well as 100,000 others) between 2009 and 2013. Astronomers, citizen scientists and computers could then search for regular dips in a star's light — a sign that an exoplanet has passed in front of that star. The largest planets might block 1 percent of a star's light, but Tabby's star dropped by as much as 20 percent in brightness. That, in and of itself, would be weird. But the periodic dimmings didn't occur at regular time intervals, either — they were sporadic. The signature couldn't be caused by a planet, scientists said.
In September, a team led by Boyajian, a postdoctoral fellow at Yale University, tried to make sense of the unusual signal. First, the researchers looked into any angles that might mean there was something wrong with the data itself. They even checked in with Kepler mission scientists. But everything came out clean. "The data that we were observing with Kepler is, in fact, astrophysical," Boyajian told Space.com.
Still, nothing about the observations indicated what might be causing the extreme interference. After considering many possible scenarios, Boyajian determined that dust from a large cloud of comets was the best explanation. But she admits that "it's a bit of a stretch to have comets that are large enough to block that much of the light from the star." With her paper published, she hoped that other astronomers would jump in with alternative solutions.
And they did. A month later, the star exploded into the public's eye when Wright announced that an advanced extraterrestrial civilization could be responsible for the signal, assuming this civilization built a megastructure, like solar panels, around the star. And Boyajian thinks the theory is definitely worth a follow-up.
"We have to look at every angle that we can — and that's one angle, as wild and crazy as it seems," she said. Slate blogger and astronomer Phil Plait, too, admits that "while it's incredibly unlikely, it does kinda fit what we're seeing."
A follow-up looking for alien signals, however, turned up empty-handed.
So Schaefer turned to old photographic plates from the Harvard College Observatory. Lucky for him, the star has been photographed more than 1,200 times as part of a repeated all-sky survey between the years 1890 and 1989. That many data points revealed that Tabby's star is acting strangely in more than one way: It's flickering on short timescales, as the Kepler and Harvard data show, and it's dimming over the course of a century, as the Harvard data show.
"Occam's razor [the simplest explanation is likely the best one] needs to be considered in a scenario like this," Boyajian said. A single phenomenon must be causing both behaviors, she added. But what is it?
Well, the results don't look good for a family of comets. It would take a vast number of comets to pass in front of the star for a century, astronomers say.
"It would be more mass than what we have in the whole Kuiper Belt" [the band of icy bodies in the vast region beyond Neptune], said Massimo Marengo, an associate professor of astronomy at Iowa State University who co-authored a paper supporting the comets theory in December.
"You can get out of that if you assume it's the same family of comets passing in front of the star over and over," Marengo told Space.com. But with the century-long dimming trend, too, that family of comets has to get bigger every time it passes the star. "It's a difficult thing to do," he said.
The results also change the requirements for the alien megastructure hypothesis. Plait pointed out that the general fading is actually what you'd expect to see if aliens were building a massive sphere around their star. But before you get your hopes up, consider this: Plait calculated that aliens would need to build a minimum of 750 billion square kilometers (290 billion square miles) of solar panels to account for the 20 percent drop in their star's brightness. "That's 1,500 times the area of the entire Earth," Plait wrote. "Yikes."
So astronomers now have to hope that future observations might shed light on this stellar oddity. "Nature can help us by creating another one of these events," Marengo said. "But sometimes, we don't get lucky."
Did scientists find a giant alien structure around KIC 8462852? Probably not, but if they did, what would these structures look like?
In the summer of 2015, astronomers announced a strange new discovery from NASA’s planet hunting Kepler space observatory. Some object was blocking out about 22% of the light from its parent star: KIC 8462852. Even the largest planet in the Solar System, Jupiter, would only block out 1% of a star’s light, so something much larger must be doing this. But what?
Astronomers proposed a few ideas: a cloud of comets, or a maybe the debris from a recently destroyed planet. But another idea was put on the table: an alien megastructure.
Now keep in mind, aliens are way down in the list of possibilities here. It’s almost certainly, for sure, probably not aliens. Seriously, every other possibility is a zillion times more likely than aliens. But there’s a remote, non-zero chance that it’s aliens, and their alien megastructures.
Are you having trouble imagining what an alien megastructure might look like, and why it would exist? No problem, join the club. All we’re doing is extrapolating from our current demand and growth for energy to its logical conclusion.
Imagine the future of humanity. We use more energy now than we did in the past. And in the future, we’ll want even more energy. Eventually we’ll use up all the energy on Earth, then we’ll figure out how to use up all the energy flowing out of the Sun. After that, we’ll use up all the energy in the entire Milky Way. Finally, we’ll use up all the energy within every single galaxy that we can get our hands on.
The story of that alien megastructure that may exist around a distant star, blocking its light for odd periods of time—well, things just got weirder. www.area51.org/aliens-at-work/
Scientists have been puzzling over what could be causing that distant star to dim 20% or more at a time, something that stars just don’t do. Stars dim their light sometimes, sure, but only a little. Not 20% or even more. The Story So Far: Comets or an Alien Race?
There have been two proposals so far: either it’s maybe a swarm of comets (something that has been dismissed as highly unlikely), or … maybe it’s aliens. Specifically, maybe aliens built a gigantic megastructure around the star, and that’s what’s responsible for the dimming of star KIC 8462852 (also known as “Tabby’s Star” after astronomer Tabetha Boyajian who noticed the phenomenon). Some scientists went as far as to speculate that the star may be encompassed by a Dyson Sphere, a hypothetical energy-gathering structure first proposed by physicist Freeman Dyson. A Dyson Sphere that was constructed by an alien race.
Astronomers still can’t rule out the presence of an alien megastructure around Kepler star KIC 8462852 — located nearly 1500 light years away in the constellation of Cygnus. Strange dips in the star’s luminosity over four years of observations with NASA ’s Kepler space telescope initially fueled such speculation, even though most of it was quickly dismissed.
But the currently most favored natural explanation for the strange light curves — a swarm of intervening planetary or cometary debris — remains largely unsatisfying. Thus, next month, a Kickstarter campaign will fund new ground-based observations to begin this summer that should bring more clarity to the situation.
“I don’t know a single professional [astronomer] that thinks this is an artificial structure, but until we look, we can’t rule it out,” Yale University astronomer Tabetha Boyajian, the crowdfunding project’s team leader, told me.
A planet transiting the star would cause a periodic dip that repeats regularly, Travis Metcalfe, a team member and astronomer at the Space Science Institute in Boulder, Colo., told me.
“But the observed dips didn’t repeat regularly, which is why continued observations from telescopes on the ground will be so helpful in narrowing down the cause,” said Metcalfe.
Two to three years of continuous observations using the Las Cumbres Observatory Global Telescope Network (LCOGT), will in theory enable to the team to spectroscopically-identify material around the star itself. “The most puzzling thing is that it looked like a normal star for most of the four years that Kepler observed it,” said Metcalfe. “But on a few occasions something eclipses up to 20% of the light for days at a time. It’s not like anything we’ve ever seen before.”
Metcalfe says that the prevailing natural explanation is that a comet could have been broken up by the gravity and/or the heat of the star so that when it returns on the next orbit it is in a bunch of smaller pieces, each of which causes a dip in the starlight at closely-spaced times.
But if the star’s dips in luminosity are caused by passing comets’ dusty tails, then that, in turn, should show up in the new spectroscopic observations, says Jason Wright, an astronomer at Penn State University and also a team member. Dust blocks blue light more efficiently than red light so, by comparing the dimming at different frequencies, we can get a handle on the amount and size of the dust in the putative comets’ tails. “If a very large number of very large comets passed between Earth and the star, they could each block enough light to be detectable,” said Wright.
And if the cause is artificial?
If it’s a big solid object or even a swarm of big objects, says Wright, then we expect to see all wavelengths dim equally — red and blue alike.
Metcalfe notes that the biggest luminosity dips happen roughly two years apart. He says it’s possible to imagine that they could be caused by a “massive artificial structure” surrounding an earth-like planet orbiting at a habitable distance from the star.
If such large dips continue to show up in future observations, says Metcalfe, it decreases the odds of a natural explanation. He says that’s because planetary collisions that could create such a swarm of transitory debris are few and far between.
Alien megastructures – aka Dyson spheres – around a star 1,500 light-years away?! Astronomers struggle to explain the most mysterious star in the universe.
KIC 8462852 – aka Tabby’s star – hit the headlines in October, 2015. That’s when astronomers from Pennsylvania State University released a preprint suggesting that observations of the star’s weirdly fluctuating light were consistent with a swarm of alien-constructed megastructures. This week, astronomers at Vanderbilt University in Nashville, and elsewhere, announced their new study of this star, in which they duke it out with a Louisiana State University astronomer over an aspect of the star’s story. The new study supports natural causes, not alien activity, to explain the mystery star. It’s one more study in what’s sure to be many, many studies to come on KIC 8462852.
The strange fluctuations in this star’s light are what caused Yale astronomer Tabetha (Tabby) Boyajian, who first noticed the star and who described it in a TED talk in February, to call it:
… the most mysterious star in the universe.
The Vanderbilt astronomers and their colleagues weren’t addressing the part of the story related to the star’s strange light-curve observed by the Kepler planet-hunting spacecraft. Everyone agrees that KIC 8462852’s light can appear strongly and weirdly irregular, with anywhere from a fraction-of-a-percent to around 20 percent of the star’s light sometimes apparently blocked. That’s why astronomers began talking about alien megastructures, aka Dyson spheres, in the first place. These vast hypothetical structures are one explanation – the most glamorous of the possible explanations – for what might be periodically blocking the star’s light.
Instead, the astronomers at Vanderbilt and elsewhere were addressing a study released in January, 2016 by astronomer Bradley E. Schaefer at Louisiana State University.
Schaefer’s work had suggested a long-term dimming in Tabby’s star, a brightness decrease by 20 percent over the last century. That finding difficult to explain by natural means but consistent with the idea that aliens were gradually converting the material in the star’s planetary system into giant megastructures. Schaefer’s study has now been accepted for publication in the peer-reviewed Astrophysical Journal.
The more recent study – whose lead author is German amateur astronomer Michael Hippke – is also accepted for publication in the Astrophysical Journal. It takes issue with Schaefer’s study and concludes in a statement from Vanderbilt:
… there is no credible evidence that the brightness of the star been steadily changing over this [100-year] period.
Vanderbilt doctoral student Michael Lund was the astronomer who first noted that Schaefer’s study was based on data from a unique resource: Digital Access to a Sky Century@Harvard. DASCH consists of more than 500,000 photographic glass plates taken by Harvard astronomers between 1885 and 1993.
Lund wondered if the apparent 100-year dimming of Tabby’s star might not be real, but instead caused by the fact that many different telescopes and cameras were used during the past century to study it. Keivan Stassun, Lund’s advisor, explained:
Whenever you are doing archival research that combines information from a number of different sources, there are bound to be data precision limits that you must take into account. In this case, we looked at variations in the brightness of a number of comparable stars in the DASCH database and found that many of them experienced a similar drop in intensity in the 1960s.
That indicates the drops were caused by changes in the instrumentation not by changes in the stars’ brightness.
Brad Schaefer, on the other hand, stands by his claim that the star has dimmed over the past 100 years, by more than the team at Vanderbilt can explain. In an email on May 10, 2016, he told EarthSky:
The long-term dimming is alive and well.
Schaefer said that independent measures by “the most expert people in the world” show that Tabby’s star has indeed faded, saying:
I have heard on good authority that another group has found Tabby’s star to be fading with other datasets … The problem with the Hippke paper is that they have included stars and measures that no experienced person would use.
So the debate about the bizarre light of KIC 8462852 continues. And even Michael Hippke admits:
The dips found by Kepler are real. Something seems to be transiting in front of this star, and we still have no idea what it is!
Hippie also mentioned that “thousands” of amateur astronomers around the world are now joining the pros in turning their thoughts and pointing their telescopes toward Tabby’s star:
… snapping images and sending them to the American Association of Variable Star Observers in hopes of detecting further dips that will shed new light on this celestial mystery.
Bottom line: Astronomers are duking it out on the subject of whether mystery star KIC 8462852 – aka Tabby’s Star – has decreased in brightness by 20 percent over the past century.
"Why Does Star KIC 8462852 Keep Dimming?" --The Kepler-Mission Mystery Endures (VIDEO)
June 13, 2016
Why does star KIC 8462852 keep wavering? Nobody knows. A star somewhat similar to our Sun, KIC 8462852 was one of many distant stars being monitored by NASA's robotic Kepler satellite to see if it had planets. Citizen scientists voluntarily co-inspecting the data along with computers found this unusual case where a star's brightness dropped at unexpected times by as much as 20 percent for as long as months -- but then recovered. Common reasons for dimming -- such as eclipses by orbiting planets or stellar companions -- don't match the non-repetitive nature of the dimmings.
A currently debated theory is dimming by a cloud of comets or the remnants of a shattered planet, but these would not explain data indicating that the star itself has become slightly dimmer over the past 125 years. Nevertheless, featured here is a NASA/APOD artist's illustration of a planet breaking up, drawn to depict NGC 2547-ID8, a different system that shows infrared evidence of such a collision.
Recent observations of KIC 8462852 did not detect the infrared glow of a closely orbiting dust disk, but gave a hint that the system might have such a disk farther out. Future observations are encouraged and creative origin speculations are sure to continue.
KIC 8462852 is situated above the Milky Way, between the Cygnus and Lyra constellations. This past October, 2015, a group of citizen scientists from the Planet Hunters program were examining data obtained from NASA’s Kepler Space Telescope when they noticed the bizarre light pattern of the star, called KIC 8462852. Among the 150,000 stars examined by the Kepler Telescope, this is the only one to show light flickering irregularly with unparalleled dips in brightness.
“We’d never seen anything like this star,” Planet Hunters overseer Tabetha Boyajian told The Atlantic. “It was really weird. We thought it might be bad data or movement on the spacecraft, but everything checked out.”
Astronomers have raised $100,000 via Kickstarter to observe KIC 8462852, or Tabby’s Star, sometimes called the most mysterious star in the universe.
An artist’s concept of a Dyson sphere. Image via energyphysics.wikispaces.com.
Here’s something you might not realize about professional astronomical observations: they cost money. Telescope time at major professional observatories doesn’t run cheap. That’s why astronomers sounded so excited on June 16, 2016, when they announced the success of their ongoing Kickstarter campaign to raise $100,000 in order to conduct a year’s worth of continuous monitoring of a star officially called KIC 8462852, also known as Tabby’s Star for astronomer Tabetha Boyajian of Yale. Boyajian and her colleagues, and various others astronomers, think there’s a possibility (however remote) that this star might be surrounded by an alien megastructure in the process of being built – a Dyson sphere – created to harvest the star’s energy. Boyajian wrote on June 16:
"Y’all are amazing! WE DID IT! … Every single penny raised over the $100,000 goal will go to observing the star longer than the one year planned in the project’s description. In fact, the longer we can extend the observational monitoring of the star, better the chance we have at catching it when it dips, and catching it in a dip is critically important to understanding and characterizing what is happening in this system!"
The astronomers’ plan is to purchase telescope time on many small telescopes around the world, in order to monitor of Tabby’s Star continuously over a year (or more, depending on whether they can raise more funds now).
The star’s strange fluctuations, or dips, were first noticed in citizen scientist observations in the Planet Hunters project, using data collected by the Kepler spacecraft. The star’s light dips profoundly, randomly, in a way that suggests something sometimes blocks it.
But what? Alien megastructures are just one possibility.
Want to know more about Tabby’s Star? It’s surely one of the most intriguing objects to come along in astronomy for some time. Check out the video below!
By the way, do the astronomers really believe that an alien megastructure surrounds this star?
Of course they don’t. Scientists are, by nature, cautious people. They don’t typically believe something is so, unless they have evidence showing it’s so. What they have here is not evidence of an alien megastructure. What they have here, instead, is mysterious behavior from a star that might, possibly, be explained by an alien megastructure. As Boyajian wrote at Kickstarter:
"Today, there is still no widely accepted theory to what is behind this star’s strange behavior.
At this point, it’s safe to say this: Something unknown appears to be going on with Tabby’s Star. If an alien megastructure, or Dyson sphere, isn’t the answer, then something else is the answer. It might even be something we’ve never considered about the physics of stars or … something else.
Thus the year-long observations of Tabby’s Star, made possible by all of you who contributed to the Kickstarter campaign, should reveal something interesting, and maybe new, in astronomy."
Finder chart for KIC 8462852, aka Tabby’s Star. It’s located in the direction to the constellation Cygnus, which is part of the famous Summer Triangle asterism, visible at this time of year. Image via Tabetha Boyajian.
Bottom line: Astronomers have raised $100,000 via Kickstarter to conduct year-long, continuous observations of KIC 8462852, or Tabby’s Star, the mysterious star that might be surrounded by an alien megastructure, or Dyson sphere.
Natural causes, not aliens, explain mystery star’s behaviour
Vanderbilt University Press Release 10 May 2016
Artist’s impression of an orbiting swarm of dusty comet fragments, which are a possible explanation for the unusual light signal of KIC 8462852, popularly known as Tabby’s star, about 1,480 light-years away in the constellation Cygnus. Image creditNASA/JPL-Caltech.
Sorry, E.T. lovers, but the results of a new study make it far less likely that KIC 8462852, popularly known as Tabby’s star, is the home of industrious aliens who are gradually enclosing it in a vast shell called a Dyson sphere.
Public interest in the star, which sits about 1,480 light-years away in the constellation Cygnus, began last autumn when Yale astronomer Tabetha (“Tabby”) Boyajian and colleagues posted a paper on an astronomy preprint server reporting that “planet hunters” — a citizen science group formed to search data from NASA’s Kepler space telescope for evidence of exoplanets — had found unusual fluctuations in the light coming from the otherwise ordinary F-type star (slightly larger and hotter than the Sun).
The most remarkable of these fluctuations consisted of dozens of uneven, unnatural-looking dips that appeared over a 100-day period indicating that a large number of irregularly shaped objects had passed across the face of the star and temporarily blocked some of the light coming from it.
Media interest went viral last October when a group of astronomers from Pennsylvania State University released a preprint that cited KIC 8462852’s “bizarre light curve” as “consistent with” a swarm of alien-constructed megastructures.
The attention caused scientists at the SETI Institute to train its Alien Telescope Array on the star to see if they could detect any radio signals indicating the presence of an alien civilisation. In November it reported finding “no such evidence” of signals with an artificial origin.
Then a study released in January by a Louisiana State University astronomer threw even more fuel on the fire of alien speculation by announcing that the brightness of Tabby’s star had dimmed by 20 percent over the last century: a finding particularly difficult to explain by natural means but consistent with the idea that aliens were gradually converting the material in the star’s planetary system into giant megastructures that have been absorbing increasing amounts of energy from the star for more than a century. That study has now been accepted for publication in the peer reviewed Astrophysical Journal.
However, a new study — also accepted for publication in the Astrophysical Journal — has taken a detailed look at the observations on which the LSU study was based and concluded there is no credible evidence that the brightness of the star been steadily changing over this period.
When the LSU study was posted on the physics preprint server arXiv, it caught the attention of Vanderbilt doctoral student Michael Lund because it was based on data from a unique resource: Digital Access to a Sky Century@Harvard. DASCH consists of more than 500,000 photographic glass plates taken by Harvard astronomers between 1885 and 1993, which the university is digitising. Lund was concerned that the apparent 100-year dimming of Tabby’s star might just be the result of observations having been made by a number of different telescopes and cameras that were used during the past century.
Lund convinced his advisor, Professor of Physics and Astronomy Keivan Stassun, and a frequent collaborator, Lehigh University astronomer Joshua Pepper, that the question was worth pursuing. After they began the study, the Vanderbilt/Lehigh group discovered that another team — German amateur astronomer Michael Hippke and NASA Postdoctoral Fellow Daniel Angerhausen — were conducting research along similar lines. So the two teams decided to collaborate on the analysis, which they wrote up and submitted to the Astrophysical Journal.
“Whenever you are doing archival research that combines information from a number of different sources, there are bound to be data precision limits that you must take into account,” said Stassun. “In this case, we looked at variations in the brightness of a number of comparable stars in the DASCH database and found that many of them experienced a similar drop in intensity in the 1960’s. That indicates the drops were caused by changes in the instrumentation not by changes in the stars’ brightness.”
Even if aliens are not involved, Tabby’s star remains “the most mysterious star in the universe” as Boyajian described it in a TED talk she gave last February.
The planet hunters first detected something unusual in the star’s light curve in 2009. They found a 1 percent dip that lasted a week. This is comparable to the signal that would be produced by a Jupiter-sized planet passing in front of the star. But planets produce symmetric dips and the one they found was decidedly asymmetric, like something that would be produced by an irregular-shaped object like a comet.
The light from the star remained steady for two years, then it suddenly took a 15 percent plunge that lasted for a week.
Another two years passed without incident but in 2013 the star began flickering with a complex series of uneven, unnatural looking dips that lasted 100 days. During the deepest of these dips, the intensity of the light coming from the star dropped 20 percent. According to Boyajian it would take an object 1,000 times the area of the Earth transiting the distant star to produce such a dramatic effect.
“The Kepler data contains other cases of irregular dips like these, but never in a swarm like this,” said Stassun.
Boyajian and her colleagues considered a number of possible explanations, including variations in the star’s output, the aftermath of an Earth/Moon type planetary collision, interstellar clumps of dust passing between the star and earth, and some kind of disruption by the star’s apparent dwarf companion. However, none of their scenarios could explain all of the observations. Their best explanation was a giant comet that fragmented into a cascade of thousands of smaller comets. (This hypothesis took a hit when the LSU study was announced because it could not explain a century-long dimming.)
“What does this mean for the mystery? Are there no aliens after all? Probably not! Still, the dips found by Kepler are real. Something seems to be transiting in front of this star and we still have no idea what it is!” Hippke summarised.
The Kepler telescope is no longer collecting data in the Cygnus region, but Hippke reports that the mystery has captured the imagination of amateur astronomers around the world so thousands of them are pointing their telescopes at Tabby’s star, snapping images and sending them to the American Association of Variable Star Observers (AAVSO) in hopes of detecting further dips that will shed new light on this celestial mystery.
Yeah it's their job to deny what they don' understand. There was a book series that was pretty cool..Ringworld. I think Larry Niven will enjoy this A lot of what was science fiction might be science one day
the expedition's goal is to explore a ringworld: an artificial ring about one million miles (1.6 gigameters) wide and approximately the diameter of Earth's orbit (which makes it about 600 million miles (1,000 gigameters) in circumference), encircling a sunlike star. It rotates, providing artificial gravity that is 99.2% as strong as Earth's gravity through the action of centrifugal force. The ringworld has a habitable, flat inner surface equivalent in area to approximately three million Earth-sized planets. Night is provided by an inner ring of shadow squares which are connected to each other by thin, ultra-strong wire (shadow-square wire).
Tabby's Star (KIC 8462852) Featured in Popular Mechanics!
Scientists Are Now Even More Confused By Potential "Alien Superstructure"
After observing Tabby's Star for four years, results only provoke more questions.
By Sophie Weiner Aug 6, 2016
Within our own galaxy, some astronomers believe there may be a massive piece of alien technology, built to harvest energy from a distant star. The star, KIC 8462852, also known as Tabby's Star, exhibits strange behavior, flickering and dimming, that can't be explained by any known astronomical phenomena. A new, unpublished study posted to arXiv, reports the results of studying images of the star from the Kepler Telescope over the past four years. The paper shows shocking results: the star's luminosity varied, sometimes dipping by 20% over the course of the study period. Even more perplexingly, its total luminosity, or flux, diminished by 4% overall over that time.
"The part that really surprised me was just how rapid and non-linear [the dimming] was," study author Ben Montet of Caltech told Gizmodo. "We spent a long time trying to convince ourselves this wasn't real. We just weren't able to."
Tabby's Star was first observed in the 19th century, providing scientists plenty of data to reference in their search for answers. Another researcher, Bradley Schaefer of Louisiana State University, published a study earlier this year claiming that the light output of the star has decreased by 19% in 100 years. His claims were highly disputed. Now, this data seems to back up the assertion that the star is dimming at an astonishingly rapid rate, even if Schaefer's data is not totally accurate.
One of the explanations for this phenomena, and the one that has received the most press, is the idea that the star could be flickering and dimming due to an "alien superstructure" that extraterrestrial beings are building around their star as a way, perhaps, to collect energy (these hypothetical structure are known as Dyson spheres). Though there's been no proof of this hypothesis, it also can't be ruled out. The other theories, including that the star is blocked by the debris of a smashed planet, or what's known as "gravity darkening," would go towards explaining parts of the phenomenon, but no current theory could explain it entirely.
"The new paper states, and I agree, that we don't have any really good models for this sort of behavior," Jason Wright, the Penn State astronomer who first suggested the alien superstructure theory said. "That's exciting!"
Astronomer Brad Schaefer at LSU is one of my son's buddies. Tabetha Boyajian recently interviewed at LSU and has decided to join their astronomy team. Dave keeps me updated on any news from LIGO, (magnetic waves) or from "Tabby's Star".
If you follow such things, you'll remember when KIC 8462852, or Tabby’s star -- named after the woman who discovered it, Tabitha Boyajian -- first exploded onto the nerdscape in October of 2015. That's when scientists scouring through data from NASA's Kepler Mission first noticed its weird behavior. That star sure is weird The Kepler mission "is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planets in or near the habitable zone and determine the fraction of the hundreds of billions of stars in our galaxy that might have such planets."
It does it by measuring the light from far away stars, and noting as planets pass between the star and the Kepler photometer. So far, Kepler has discovered more than 2,700 stars that have planet candidates in their orbit, and it's just getting started.
But while one group of scientists was digging through the Kepler data, they discovered an anomaly: Tabby's star — 1,480 light years away in the constellation Cygnus — was not behaving at all like a star its size and age, but instead, was dimmer than it should be and also periodically flickering.
Those findings were published last October at the online site "arXiv" in an articled called "Planet Hunters X. KIC 8462852 – Where’s the flux?". The basic premise was: "We've noticed this happening, but we don't really have any idea why."
The team suggested a few of the most likely "whys" in that original paper.
"We presented an extensive set of scenarios to explain the occurrence of the dips," they wrote, "most of which are unsuccessful in explaining the observations in their entirety. However, of the various considered, we find that the break-up of a exocomet provides the most compelling explanation."
The article called for a lot more study and observation of Tabby's star so astronomers could unravel the mystery. Science scratched its head, said "that's a good idea" and agreed to take a closer look.
That would have been that, except for the fact that we humans are what we are.
Predictably, the web reacted in the same way as creationists trying to get intelligent design into public schools: "We don't know what it is" the web screamed, "IT MUST BE ALIENS!"
Whoa, Tex! But none of the scientific studies so far mention the possibility of aliens, or extraterrestrial civilizations. But that hasn't stopped sites like Sky and Telescope, and SETI (Search for ExtraTerrestrial Intelligence) Institute from at least entertaining the idea that it was an artificial construct.
It's fun to think about, but — buzz kill that science is — the answer to this puzzle isn't likely to be a Dyson sphere. Unfortunately, knowing what it isn't doesn't do us much good and, since the original article, there has been just a trickle of research about KIC 8462852. The most important advance on the story came out in November and threw big shade at the exocomet theory. Okay, that star is REALLY weird Last week, a new paper on Tabby's star came out and a new set of astronomers found new weirdness and came to the unsettling conclusion that "No known or proposed stellar phenomena can fully explain all aspects of the observed light curve."
Say what? The new research, authored by Caltech astronomer Ben Montet and Joshua Simon of the Carnegie Institute, adds a new layer of questions to Tabby's star.
"There are now three effects observed: the short term flickering from the original paper (Boyajian et al.)," Montet told VOA. "...a long-term dimming over the Kepler mission and possibly for a century, and a rapid decline in the overall flux by 2.5 percent, which wasn't previously observed before." So, Montet says, "Any model that wants to explain the observed light curve now has to explain all three of these." A tall order.
But Montet made this point to VOA: "I want to clarify that this is 'no known or proposed *stellar* phenomena,' meaning phenomena intrinsic to the star itself."
Darn science! That takes a lot of the fun out of the mystery, because Montet is suggesting that the answer is likely to be found between our telescopes and Tabby's star: "some material between us and the star blocking the light," a giant dust cloud perhaps, that dims the light like a sandstorm dims our sun.
"However, we don't know what that material is [maybe it's remnants from a collision of planetesimals], or why it's causing a long-term dimming," Montet added. "We've seen disintegrating planetesimals before, but never something that looks like this. Kepler is the first opportunity that has given us enough time resolution and photometric precision to see these events; it looked at 200,000 stars [approximately] and found one of these, so it's pretty rare."
That pretty much takes the air out of the alien idea, but not the mystery itself.
If it's a cloud of some kind, it "would need to be at impossibly large distances from the star or be slowly increasing in surface density." That's not likely, the paper says. "Moreover, such a model does not naturally account for the long-term dimming in the light curve ... suggesting that this idea is, at best, incomplete."
Everyone involved says the truth is out there, but science is hard. Wrap your head around the fact that we can find planets orbiting a star 1,500 light years away. And then marvel at the complexity of solving a real mystery like this one. But we're trying. Over the next year, Tabby's star is going to get a lot more telescope time, and the attention of astronomy's big brains who say they are determined to find an answer to the mystery.
It's just a matter of time, according to Montet.
"The way the light is blocked during a large dip at different wavelengths will tell us a lot about what the material doing the blocking is," he told VOA "...is it a solid body, or a cloud of diffuse gas and dust? The LCOGT [Las Cumbres Observatory Global Telescope Network] is planning observations, and there are already a network of amateur astronomers through the AAVSO [American Association of Variable Star Observers] obtaining observations, which will be very important for understanding this system."
Some astronomers think this star may have an alien megastructure – an energy-gathering Dyson sphere – around it. Here’s the latest.
Remember Tabby’s Star? It’s the star that astronomer Tabetha Boyajian – who reported its strangeness in a Ted Talk in February, 2016 – famously called “the most mysterious star in the galaxy.” It’s mysterious because astronomers have never seen another star do what this star does. One explanation for the strange dimming of its light is that the star has an alien-built megastructure – a Dyson sphere – around it. Does it? Will we ever know for sure? Those are unanswered questions, but, while you’re pondering it, here’s the latest on this wonderful star.
On August 3, 2016, two astronomers added more evidence that Tabby’s Star – also known as KIC 8462852 – is just plain strange. Benjamin Montet with the California Institute of Technology and Joshua Simon with Observatories of the Carnegie Institution of Washington have uploaded their paper to the arXiv preprint server detailing their study of the star by analyzing data from the NASA’s Kepler space telescope (a famed planet-finding telescope) over the past four years.
They found that the star has been decreasing in brightness at an unprecedented rate.
Finder chart for KIC 8462852. It’s located in the direction to the constellation Cygnus, which is part of the famous Summer Triangle asterism, visible at this time of year.
Now here’s some history. It’s the job of the Kepler spacecraft to look for tiny dips in a star’s light, caused by possible planets passing in front of the star. Professional astronomers analyzing data from Kepler, and citizen scientists from the Planet Hunters crowdsourcing program, noticed the star KIC 8462852 from among the 150,000 stars examined by Kepler. They noted that it is “strange” and “bizarre.” Tabitha Boyajian first reported anomalies in the unusual light curve of star KIC 8462852—over the years 2009 to 2013. Its light appeared to dip in ways that did not conform to what would be expected if it were due to a planet passing in front of it, temporarily blocking some of its light.
Her paper led to observations, commentaries and theories from others in the space community. In June, astronomers raised more than $100,000 from a Kickstarter campaign to be able to study the star further.
But no one has been able to come up with a reasonable explanation for Tabby’s Star. One idea is that comet swarms surround the star. Another is similar, but it’s planetary remnants, not comets. Then there’s the exceedingly satisfying and exciting idea that the dips in the star’s light might be due to an alien megastructure being built around the star. So far, none of the theories has been able to take into account all of the odd observations.
Earlier this year, Bradley Schaefer with Louisiana State University published results of his efforts studying photographic plates that had captured the star going back to the 19th century (see EarthSky’s article about Schaefer’s research here). He reported that a long-term dimming in the light from the star by nearly 20 percent over just the past century. That result might suggest a megastructure in the process of being built, hiding more and more of the star’s light from our view. His report was not received warmly by all, but Schaefer answered back that the criticisms were unfounded.
And now, using a different approach, Montet and Simon have found something similar to what Schaefer found. They studied images from Kepler and found that light from Tabby’s Star had decreased in brightness by approximately .34 percent a year for 1,000 days starting in 2009, which was actually twice the rate that Schaefer had found.
Even stranger, they found that over the next 200 days, the brightness of the star dimmed by another 2.5 percent before it finally leveled out.
Why don’t astronomers just turn their telescopes on this star, and figure it out? Because telescope time is expensive. Hence Boyajian’s recent and thankfully successful Kickstarter campaign.
So the mystery continues. Along with many in the astronomical community, we’ll be watching for more news!
Tabetha Boyajian, who helped bring mystery star KIC 8462852 to public attention. Image via exoplanets.astro.yale.edu
Latest study of Tabby's star offers more weirdness
August 9, 2016 by Bob Yirka weblog
A pair of researchers has added more evidence regarding the oddity of KIC 8462852, aka Tabby's Star. Benjamin Montet with the California Institute of Technology and Joshua Simon with Observatories of the Carnegie Institution of Washington have uploaded a paper to the arXiv preprint server detailing their study of the star by analyzing data from the Kepler space observatory over the past four years. They found that the star has been decreasing in brightness at an unprecedented rate.
The tale of Tabby 's Star began in September of last year when Louisiana State University astronomer Tabetha Boyajian reported anomalies in the unusual light curve of star KIC 8462852—over the years 2009 to 2013, its light appeared to dip in ways that did not conform to what would be expected if it were due to a planet passing in front of it, temporarily blocking some of its light. Her paper led to observations, commentaries and theories from others in the space community, though no one was able to come up with a reasonable explanation for what she had found. One researcher actually proposed that it might be due to alien activity. Then, earlier this year, Bradley Schaefer with Louisiana State University published results of his efforts studying photographic plates that had captured the star going back to the 19th century—he reported that the light from the star had dimmed 19 percent over just the past century. His report was not received warmly by all, as many suggested his data or approach was likely flawed.
But now, another team has found something similar. Montet and Simon studied images from the space-based Kepler observatory and found that light from Tabby's Star had decreased in brightness by approximately .34 percent a year for 1000 days starting in 2009, which was actually twice the rate that Schaefer had found. Even stranger, they found that over the next 200 days, the brightness of the star dimmed by another 2.5 percent before it finally leveled out.
Various scientists have offered possible explanations for the strange behavior of Tabby's star—from comet swarms to planetary remnants to the construction of a Dyson Sphere-like structure around the star to capture its energy by aliens—but so far, none of the theories has been able to take into account all of the odd observations. That may change soon, however, as Boyajian, the astronomer who first noticed the star's strange behavior, ran a successful crowdsourcing campaign to pay for time at the Las Cumbres Observatory Global Telescope Network over the course of a year—this will give her a chance to catch the star in the act of blinking, allowing her to alert the rest of the astronomy community, which will presumably its sights on the star at once, and in so doing, perhaps solve the mystery.
The bizarre object’s overall brightness has been gradually dimming for years
By Mike Wall, SPACE.com October 5, 2016
The more scientists learn about "Tabby's Star," the more mysterious the bizarre object gets.
Newly analyzed observations by NASA's planet-hunting Kepler space telescope show that the star KIC 8462852—whose occasional, dramatic dips in brightness still have astronomers scratching their heads — has also dimmed overall during the last few years.
"The steady brightness change in KIC 8462852 is pretty astounding," study lead authorBen Montet, of the California Institute of Technology in Pasadena, said in a statement.
"Our highly accurate measurements over four years demonstrate that the star really is getting fainter with time," Montet added. "It is unprecedented for this type of star to slowly fade for years, and we don't see anything else like it in the Kepler data."
KIC 8462852 hit the headlines last September, when a team of astronomers led by Tabetha Boyajian of Yale University announced that the star had dimmed dramatically several times over the past few years—in one case, by a whopping 22 percent.
These brightness dips are too significant to be caused by an orbiting planet, so scientists began suggesting alternative explanations. Perhaps a planet or a family of orbiting comets broke up, for example, and the ensuing cloud of dust and fragments periodically blocks the star's light. Or maybe some unknown object in the depths of space between the star and Earth is causing the dimming.
The brightness dips are even consistent with a gigantic energy-collecting structure built by an intelligent civilization—though researchers have been keen to stress that this "alien megastructure" scenario is quite unlikely.
The weirdness increased in January 2016, when astronomer Bradley Schaefer of Louisiana State University reported that KIC 8462852 also seems to have dimmed overall by 14 percent between 1890 and 1989.
This conclusion is based on Schaefer's analysis of photographic plates of the night sky that managed to capture Tabby's Star, which lies about 1,500 light-years from Earth. Some other astronomers questioned this interpretation, however, suggesting that differences in the instruments used to photograph the sky over that time span may be responsible for the apparent long-term dimming.
So Montet and co-author Joshua Simon, of the Observatories of the Carnegie Institution of Washington, decided to scour the Kepler data for any hint of the trend Schaefer spotted. And they found more than just a hint.
Kepler observed KIC 8462852, along with about 150,000 other stars, from 2009 through 2013. During the first three years of that time span, KIC 8462852 got nearly 1 percent dimmer, Montet and Simon found. The star's brightness dropped by a surprising 2 percent over the next six months, and stayed level for the final six months of the observation period. (Kepler has since moved on to a new mission called K2, during which the telescope is hunting for exoplanets on a more limited basis and performing a variety of other observations.)
"This star was already completely unique because of its sporadic dimming episodes," Simon said in the same statement. "But now we see that it has other features that are just as strange, both slowly dimming for almost three years and then suddenly getting fainter much more rapidly."
Montet and Simon said they don't know what's behind the weird behavior of Tabby's Star, but they hope their results, which have been accepted for publication in The Astrophysical Journal, help crack the case eventually.
"It's a big challenge to come up with a good explanation for a star doing three different things that have never been seen before," Montet said. "But these observations will provide an important clue to solving the mystery of KIC 8462852."
'Alien Megastructure' Star Targeted by $100 Million SETI Search
By Mike Wall, Space.com Senior Writer October 26, 2016
If intelligent aliens actually do live around Tabby's star, astronomers are determined to find them.
The Breakthrough Listen initiative, which will spend $100 million over the next 10 years to hunt for signals possibly produced by alien civilizations, is set to begin studying Tabby's star with the 330-foot-wide (100 meters) Green Bank Telescope in West Virginia, project team members announced Tuesday (Oct. 25).
"The Green Bank Telescope is the largest fully steerable radio telescope on the planet, and it's the largest, most sensitive telescope that's capable of looking at Tabby's star given its position in the sky," Breakthrough Listen co-director Andrew Siemion, who also directs the Berkeley SETI (Search for Extraterrestrial Intelligence) Research Center at the University of California, Berkeley, said in a statement.
"We've deployed a fantastic new SETI instrument that connects to that telescope, that can look at many gigahertz of bandwidth simultaneously and many, many billions of different radio channels all at the same time so we can explore the radio spectrum very, very quickly," Siemion added.
The observations will take place for 8 hours per night for three nights over the next two months, with the first observations set to take place Wednesday (Oct. 26), project team members said.
Tabby's star, officially known as KIC 8462852, lies about 1,500 light-years from Earth. Observations by NASA's Kepler space telescope showed that the star dimmed dramatically several times over the past half-decade or so, at one point by a whopping 22 percent. These occasional brightness dips — which were first reported last year by a team led by Yale University postdoc Tabetha Boyajian (hence the star's nickname) — are far too substantial to be caused by an orbiting planet, astronomers have said.
So researchers have offered up a number of alternative explanations for the dimming to date. Perhaps a cloud of comet fragments periodically blocks the star's light, for example, or maybe some unknown structure in the depths of space between Earth and Tabby's star is responsible.
It's even possible that the brightness dips are caused by an "alien megastructure" — an enormous collection of energy-gathering solar panels, for example.
Astronomers have stressed that the megastructure hypothesis is a long shot, but long shots shouldn't be dismissed out of hand, Breakthough Listen team members said.
"I don't think it's very likely — a one-in-a-billion chance or something like that — but nevertheless, we're going to check it out," Dan Werthimer, chief scientist at Berkeley SETI, said in the same statement. "But I think that E.T., if it's ever discovered, it might be something like that. It'll be some bizarre thing that somebody finds by accident … that nobody expected, and then we look more carefully and we say, 'Hey, that's a civilization.'"
A number of other research teams have already searched for signals coming from Tabby's star, and all of those searches have come up empty so far. Siemion, Boyajian and astronomer Jason Wright, who's based at Pennsylvania State University, will discuss the planned Tabby's star observations during a video chat from the Green Bank Telescope site on Wednesday at 4 p.m. EDT (2000 GMT). You can watch it live here: .
Mystery of 'Alien Megastructure' Star Testing Astronomers' Creativity
By Mike Wall, Space.com Senior Writer December 21, 2016
SAN FRANCISCO — Astronomers may have to think a little harder to solve the mystery of Boyajian's star.
In September 2015, Yale University's Tabetha Boyajian and her colleagues reported that the star KIC 8462852 has dimmed dramatically multiple times over the past seven years, once by an astounding 22 percent.
NASA's planet-hunting Kepler space telescope spotted these dimming events. But the brightness dips of "Boyajian's star," as it has come to be known, were far too significant to be caused by an orbiting planet, so astronomers began thinking of alternative explanations.
Researchers have come up with many possible causes for the dimming, including a swarm of broken-apart comet fragments, variability in the activity of the star itself, a cloud of some sort in the interstellar medium between Kepler and Boyajian's star, and, most famously, an orbiting "megastructure" built by an alien civilization to collect stellar energy.
Researchers are testing these hypotheses to the extent possible. For example, the $100 million Breakthrough Listen initiative is using the Green Bank Telescope in West Virginia to hunt for signals coming from Boyajian's star, which lies about 1,500 light-years from Earth.
The Green Bank observing run will wrap up next month, said team member Jason Wright, an astronomer at Pennsylvania State University. (Other research groups have used different instruments to search for signs of intelligent aliens around Boyajian's star, coming up empty to date.)
Wright has spent a fair bit of time over the past 15 months pondering what's happening with Boyajian's star; indeed, he's lead author of a recent study outlining the various possiblities.
The mystery has only deepened since Boyajian and colleagues' September 2015 paper. Early last year, for example, astronomer Bradley Schaefer of Louisiana State University determined that, in addition to the periodic brightness dips, the star dimmed overall by about 20 percent between 1890 and 1989. This result was bolstered by another 2016 study, which found that Boyajian's star dimmed by about 3 percent between 2009 and 2013.
Wright has said that the interstellar-cloud explanation seems the most likely of the proffered hypotheses. But he's not betting on it. "That would have to be some crazy interstellar cloud," he told Space.com here last week at the annual fall meeting of the American Geophysical Union.
Researchers may have to dig deeper to figure out exactly what's causing the strange dimming of Boyajian's star, Wright said.
"I think it's very likely that we haven't heard the right answer yet — that I haven't heard the right answer yet, anyway," he said.
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Aug 15, 2018 23:21:38 GMT -6
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Aug 31, 2018 2:08:32 GMT -6
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Sept 19, 2018 16:46:42 GMT -6
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lois: How did your Halloween night go this year?
Nov 15, 2018 23:54:58 GMT -6
skywalker: He posted on the Halloween thread this year.
Nov 25, 2018 18:33:36 GMT -6
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Sept 24, 2019 10:17:58 GMT -6