From The Guardian: “First contact or false alarm? New Richter-like scale for alien signals”

From The Guardian

Rio 2.0 rates potential signs of extraterrestrial life from 0 to 10, with 10 equivalent to ‘an alien shaking your hand’.

Alien seeker … Jodie Foster as Ellie Arroway in the 1997 movie Contact, based on Carl Sagan’s novel. Photograph: Rex/Shutterstock

When a team of Russian astronomers reported in 2015 that a telescope in the Caucasus region had intercepted a mysterious signal from a distant star, talk of extraterrestrials was not far behind. As some asked: was this proof aliens were trying to contact us?

The answer came soon enough. Follow-up observations from other telescopes failed to confirm the signal and researchers came to the conclusion that the source of the signal was far closer to home. The chances are it came from a passing plane or a person on a citizens band radio, or was down to a glitch in the telescope’s electronics.

It was not the first time public excitement had been whipped up by signals that turned out to be proof of something far less exciting than an advanced extraterrestrial civilisation. And in expectation that more false signals will come, scientists have now created their own Richter-like scale to explain whether a finding is a damp squib or has truly seismic implications.

The new scale allows scientists to rate interesting signals detected in searches for extraterrestrial intelligence from 0 to 10, where 0 is nothing to get excited about and 10 is equivalent to “an alien space probe orbiting the Earth or an alien shaking your hand,” said Duncan Forgan, who worked on the project, at the University of St Andrews Centre for Exoplanet Science.

There are many alternative explanations that need to be considered when evaluating a potential extraterrestrial signal. “There could be a problem with your telescope or a radio frequency coming from something on Earth,” Forgan said. “You might think you found an alien but actually you found a taxi rank.”

Known as Rio 2.0, the scale is a proposed upgrade of an existing Rio scale that is already used by the alien-hunting community. It assigns scores to Seti (“search for extraterrestrial intelligence”) signals by taking into account both the potential implications of the signal and the likelihood that it is genuine, rather than down to natural or human-made phenomena.

“We are talking about extraordinary claims here and so you need extraordinary evidence to go with them,” Forgan said. “Ideally this means multiple observations from multiple instruments – as well as from different research teams using the same instruments.”

Under the proposals, scientists could issue their own Rio scale number for any interesting signals they detect, but so could fellow academics who review their work for publication. The rating system is also being made available to the public.

“It is clear from citizen science projects that the general public are able to complete similar classification tasks with relatively low amounts of training,” the scientists write in the International Journal of Astrobiology.

There are an estimated 400bn stars in the Milky Way, and evidence shows that most have planets circling them. But with so many stars being observed, there is a constant risk of technical glitches or spurious signals masquerading as potential alien transmissions.

In one of the most recent false alarms, the periodic dimming of a star led to speculation that an advanced extraterrestrial civilisation had built an “alien megastructure” around their star to harvest all of its energy. Thousands of headlines and closer observations later, the real cause turned out to be dust.

Jill Tarter, a co-founder of the Seti Institute in Mountain View, California, and an author of the paper, said the new scale could be used like the Richter scale, which describes the severity of earthquakes.

SETI’s Jill Tarter

SETI Institute

SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA, Altitude 986 m (3,235 ft)

Drake Equation, Frank Drake, Seti Institute

Frank Drake with his Drake Equation. Credit Frank Drake

A signal is scored immediately and then continuously updated as new data arrives. More credibility will be given to discoveries with multiple independent Rio scores.

Tarter, who was the inspiration for the alien-seeking Ellie Arroway in Carl Sagan’s novel Contact and the subsequent movie with Jodie Foster, spotted potential extraterrestrial signals three times in her career, but each time found mundane explanations for them. The group of astronomers behind Rio 2.0 say it could be tested on fictional scenarios such as the one in the film, as well as on historical “false alarms” such as the famous “Wow!” signal.

Wow! signal

Andrew Siemion, another co-author, and director at the Seti Research Center at the University of California, Berkeley, added: “We absolutely encourage wide assessment of the Rio scale for any purported discovery, particularly by independent scientists. It is critical in any scientific process to have independent review of methods and interpretation.”

The new Rio Scale has been submitted to the International Academy of Astronautics Permanent Committee on Seti for official ratification.

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From astrobites: “Citizen scientists in search of failed stars”

Astrobites

May 29, 2017
Ingrid Pelisoli

Title: The First Brown Dwarf Discovered by the Backyard Worlds: Planet 9 Citizen Science Project
Authors: Marc J. Kuchner, Jacqueline K. Faherty, Adam C. Schneider et al.
First Author’s Institution: NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics Laboratory

Status: Accepted to ApJL [open access]

Not everyone can be a star. Brown dwarfs, for example, have failed on their attempt.

Artist’s concept of a Brown dwarf [not quite a] star. NASA/JPL-Caltech

These objects have masses below the necessary amount to reach pressure and temperature high enough to burn hydrogen into helium in their cores and thus earn the classification “star”. It’s not very long since we’ve learned of their existence. They were proposed in the 1960s by Dr. Shiv S. Kumar, but the first one was only observed many years later, in 1988 – and we are not even sure it is in fact a brown dwarf! We’ve only reached a substantial number of known brown dwarfs with the advent of infrared sky surveys, such as the Two Micron All Sky Survey (2MASS) and the Wide-field Infrared Survey Explorer (WISE).

Caltech 2MASS Telescopes, a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center (IPAC) at Caltech, at the Whipple Observatory on Mt. Hopkins south of Tucson, AZ, and at the Cerro Tololo Inter-American Observatory near La Serena, Chile.

NASA/WISE Telescope

Discovering and characterising cold brown dwarfs in the solar neighbourhood is one of the primary science goals for WISE. There are two ways of doing that: 1) identifying objects with the colours of cold brown dwarfs; 2) identifying objects with significant proper motion. Brown dwarfs are relatively faint objects, so they need to be nearby to be detected. We can detect the movement of such nearby targets against background stars, which are so distant that they appear to be fixed on the sky. This movement is called proper motion. As the signal-to-noise ratio is not very good for such faint objects, the second method is the preferred one. However, single exposure WISE images are not deep enough to find most brown dwarfs. This is where today’s paper enters. The authors have launched a citizen science project called “Backyard Worlds: Planet 9” to search for high proper motion objects, including brown dwarfs and possible planets orbiting beyond Pluto, in the WISE co-add images. Co-add images are simply a sum of the single exposures images taking into account corrections to possible shifts between them. This increases signal-to-noise ratio and helps to detect faint targets. On today’s paper, they report the first discovery of their project: a new brown dwarf in the solar neighbourhood, which was identified only six days after the project was launched!

Citizen science: a promising approach

The idea behind citizen science is to engage numerous volunteers to tackle research problems that would otherwise be impractical or even impossible to accomplish. The Zooniverse community hosts lots of such projects, in disciplines ranging from climate science to history. Citizen science projects have made some remarkable discoveries in astronomy, such as KIC 8462852 (aka “Tabby’s Star”, “Boyajian’s star” or “WTF star”).

Tabby’s Star is mysteriously dimming again as reported by Fairborn Observatory in Arizona.
(Photo : Unexplained/YouTube screenshot)

In “Backyard Worlds: Planet 9”, volunteers are asked to examine short animations composed of difference images constructed from time-resolved WISE co-adds. The difference images are obtained subtracting the median of two subsequent images from the image to be analysed. This way, if an object does not significantly move, it will disappear from the analysed image with the subtraction, leaving only moving objects to be detected. The images are also divided into tiles small enough to be analysed on a laptop or cell phone screen. The classification task consists in viewing one animation, which is composed of four images, and identifying candidates for two types of moving objects: “movers” and “dipoles”. Movers are fast moving sources, that travel more than their apparent width over the course of WISE’s 4.5 year baseline. Dipoles are slower-moving sources that travel less than their apparent width, so that there will be a negative image right next to a positive image, since the subtraction of the object’s flux will only be partial. An online tutorial is provided to show how to identify such objects and distinguish them from artifacts such as partially subtracted stars or galaxies, and cosmic rays.

The discovery: WISEA 1101+5400

Figure 1: Two co-adds of WISE data separated by 5 years showing how WISEA 1101+5400 has moved. The region shown is 2.0” x 1.6” in size. [Figure 2 from the paper]

Five users reported a dipole on a set of images, which can be seen here, the first report taking place only six days after the project was launched. The object, called WISEA 1101+5400, can be seen on Figure 1. This source would be undetectable in single exposure images, while in these co-adds it is visible and obviously moving. Follow-up spectra were obtained 9 using the SpeX spectrograph on the 3 m NASA Infrared Telescope Facility (IRTF).

NASA Infrared Telescope facility Mauna Kea, Hawaii, USA

The average spectrum is shown on Figure 2. Both the object’s colours and the obtained spectra are consistent with a field T dwarf, a type of brown dwarf.

Figure 2: In black, the spectrum for WISEA 1101+5400. A field T5.5 brown dwarf, SDSS J0325+0425, is shown in red for comparison. Atomic and molecular opacity sources that define the T dwarf spectral class are indicated. [Figure 3 from the paper]

Assuming WISEA 1101+5400 is the worst case scenario, i.e. about as faint an object as this survey is able to detect and with the minimum detectable proper motion, the authors estimate that “Backyard Worlds: Planet 9” has the potential to discover about a hundred new brown dwarfs. If WISEA 1101+5400 is not the worst case scenario, but objects even fainter or with lower proper motion can be found, this number could go up.

Although the discovery of only one brown dwarf might not seem worthy of celebration, this discovery demonstrates the ability of citizen scientists to identify moving objects much fainter than the WISE single exposure limit. It is yet another proof that science could use the help of enthusiasts. So if you’re not doing anything now, why not take your pick at https://www.zooniverse.org/ and help a scientist?

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Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
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Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

From Seeker: “Kepler’s ‘Alien Megastructure’ Star to Spill SETI Secrets?”

SEEKER

Oct 26, 2016 [I missed this, but it is important]
IAN O’NEILL

GBO – Green Bank Radio Telescope, Green Bank, West Virginia, USA

The star KIC 8462852 — informally known as Tabby’s Star — has been the focus of the worlds’ attention for months now, and for good reason. Its strange behavior could be a sign that there’s a super-advanced alien civilization carrying out the mother of all engineering projects in orbit. But the mysterious dips in observed light from the star could alternatively just be a huge swarm of comets or some other as-yet-to-be-understood stellar phenomenon.

Although astronomers are generally skeptical that there really is an extraterrestrial civilization constructing a starlight-blocking megastructure only 1,480 light-years from Earth, the Breakthrough Listen SETI (Search for Extraterrestrial Intelligence) project is committing radio telescope time of one of the most powerful observatories on the planet to at least test the intelligent alien hypothesis.

The project is a part of the $100 million Breakthrough Prize Foundation that’s funded by Russian entrepreneur Yuri Milner and backed by British theoretical physicist Stephen Hawking and Facebook founder Mark Zuckerberg.

Starting Wednesday (Oct. 26), a team of astronomers will use the renowned 100-meter Green Bank Telescope (pictured above) that is located deep in a radio-silent corner of West Virginia to study Tabby’s Star. For eight hours per night for three nights over the next two months, a special instrument attached to the huge radio telescope will be used to carry out an unprecedented observation campaign of the star.

“The Breakthrough Listen program has the most powerful SETI equipment on the planet, and access to the largest telescopes on the planet,” said Andrew Siemion, director of the Berkeley SETI Research Center and co-director of Breakthrough Listen, in a statement. “We can look at it with greater sensitivity and for a wider range of signal types than any other experiment in the world.”

Although other projects have tried to eavesdrop on the star before, SETI campaigns have typically been limited by the number of radio frequencies that can be recorded simultaneously and the amount of time committed to just one star in the sky. This new instrument [new only to the project, the telescope began regular science operations in 2001.] is able to record a huge amount of data across a range of frequencies at the same time, potentially allowing us to detect the radio transmissions from any transmitting intelligent aliens at Tabby’s Star.

“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,” said Siemion. “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.”

It’s estimated that up to one petabyte of data may be collected over the observing run — that’s enough data to fill a thousand computer hard drives (assuming each can store one terabyte). The researchers say that it could be over a month before we know whether or not a signal was detected because it will take a long time to process all the observations.

With Siemion, Tabetha Boyajian, from Louisiana State University, and visiting UC Berkeley astronomer Jason Wright will be heading the study. Boyajian was the first to report on KIC 8462852’s peculiar light-curve in September 2015, which was initially flagged by citizen scientists participating in the Planet Hunters project. Tabby’s Star is so-named in honor of Boyajian.

The project asks for the help of the public to look at candidate exoplanet transits from NASA’s Kepler Space Telescope. Kepler has confirmed hundreds of worlds orbiting other stars by detecting the dip in brightness of a star (described by the star’s “light-curve”) by an exoplanet passing in front — an event known as a “transit.” And the transit signal produced by Tabby’s star was as dramatic as it was bizarre.

Typically, an exoplanet signal might dim a star’s light by around 2%. But several of the irregular transits of Tabby’s Star caused the starlight to drop by up to 22%. This means that something very big must be passing in front. What’s more, it seems the star’s brightness has been dimming for hundreds of years according to historical astronomical records, only adding to the intrigue. Although several ideas have been put forward to explain the signal, the key one being the possibility of a huge cloud of comets drifting in front of the star, all have fallen short of fully explaining the Kepler observation.

After the weirdness of Tabby’s Star was known, Jason Wright discussed the possibility of Tabby’s Star’s dimming not being caused by natural phenomena; could the dimming be caused by an advanced alien intelligence creating a “megastructure” around the star? Could this be the first observational evidence of a huge solar array (like a Dyson Sphere) being built?

For now, this is pure speculation, but Breakthrough Listen hopes to investigate further. If this hypothetical alien civilization is transmitting powerful radio signals into space, perhaps we’ll detect it. Though it is highly unlikely an artificial radio signal will be detected, the mere chance Tabby’s Star might spill its secrets in the form of transmissions from an advanced alien race is enough for us to at least try.

[Also participating are Parkes Radio Telescope in Australia, and the Automated Planet Finder at UCO Lick, Mt Hamilton, California.

CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA]

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From GBO via Popular Science: “World’s Biggest Alien-Hunting Project Takes Aim At Mysterious Star”

Green Bank Radio Telescope, West Virginia, USA

Green Bank Observatory

Popular Science

Starting tonight, the Green Bank Telescope in West Virginia will point its large dish toward Tabby’s Star to listen for radio communications of any aliens potentially living there.

Tabby’s star. No image credit

Even as they acknowledge that it’s not likely, legitimate scientists are speculating about the possibility of alien life around a star named KIC 8462852 (a.k.a. “Tabby’s Star”). Today they’re going to start searching for those hypothetical aliens using the most powerful alien-hunting equipment available.

Every now and then, Tabby’s Star dims by as much as 22 percent. There’s no good explanation for what might cause such a dramatic eclipse. Even a Jupiter-sized planet would only block a tiny fraction of that. A family of extra-large comets is currently the best explanation, but even that doesn’t quite fit–scientists would expect to see more infrared (heat) coming from Tabby’s Star if comets were the case. Penn State astronomer Jason Wright proposed that a huge structure built by aliens to harvest light from the star could cause a similarly large blockage, but the lack of extra infrared radiation pours cold water on this hypothesis as well.

Regardless, Tabby’s Star is one of the most mysterious stars in the universe, so amateur and professional astronomers have been pointing their scopes toward it. They’ve searched for light and radio communications coming from any potential mega-civilizations living in the area, but to no avail so far.

Now they’re giving it everything they’ve got. The star’s discoverer, Tabetha Boyajian, is teaming up with the Breakthrough Listen project to search the radio waves around KIC 8462852 in the most thorough search for an alien presence yet.

Breakthrough Listen is the $100 million baby of Silicon Valley entrepreneur Yuri Milner. The project is working with several radio telescopes around the globe, including the Green Bank Telescope in West Virginia, the Parkes Observatory in Australia, and FAST, China’s giant alien-hunting scope. Milner’s team has developed technology that hooks up to the telescopes and can simultaneously scan billions of different radio channels to search for patterns that might indicate intelligent life.

Starting tonight, Boyajian, Wright, and astronomer Andrew Siemion (the latter two are part of the Breakthrough Listen initiative) will use the Green Bank telescope to listen for alien life around KIC 8462852. They’ll observe the star for eight hours per night on three separate nights over the next two months. Analyzing all those billions of channels will take some time–a month at least.

In tonight’s observations, the team will be scanning the 1-12 gigahertz range, which covers the frequencies that cell phones and satellite television operates, among other technologies. The scans will be “sensitive enough to a detect signal with about the same energy as a powerful aircraft surveillance radar that we have here on this planet,” said Siemion in a webcast this afternoon. “We would be sensitive to technology no more advanced than our own if indeed it exists on Tabby’s Star.”

If aliens are noisily living around Tabby’s Star, this is our best shot at finding them. However, even the scientists on this team agree that’s very, very, incredibly unlikely. Past events suspected to be alien occurrences–like the startlingly regular radio pulses that come from pulsars–have always turned out to have natural explanations. Aliens should always be the last guess, but the team thinks it’s worth giving Tabby’s Star a scan just in case.

Unfortunately, the search for alien life doesn’t have a way to prove that aliens don’t exist–there’s always the possibility that we’re not looking in the right place, at the right time, on the right wavelengths, or for the correct patterns.

“As long as Tabby’s star remains a mystery, and a possible explanation–although perhaps a remote one–is that there is an advanced civilization inhabiting the area around the star, we’re going to conduct SETI observations,” said Siemion. “This is absolutely not the end of the story with SETI and Tabby’s Star.”

Until scientists can find out what previously undiscovered phenomenon is causing the star’s mysterious blinking, aliens are pretty much as good an explanation as we’ve got.

See the full article here .

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Mission Statement

Green Bank Observatory enables leading edge research at radio wavelengths by offering telescope, facility and advanced instrumentation access to the astronomy community as well as to other basic and applied research communities. With radio astronomy as its foundation, the Green Bank Observatory is a world leader in advancing research, innovation, and education.

History

60 years ago, the trailblazers of American radio astronomy declared this facility their home, establishing the first ever National Radio Astronomy Observatory within the United States and the first ever national laboratory dedicated to open access science. Today their legacy is alive and well.

From SPACE.com: “Monster Chinese Telescope to Join Tabby’s Star Alien Hunt”

SPACE.com

FAST Chinese Radio telescope , Guizhou Province, China

The world’s largest single-dish radio telescope will join the hunt for intelligent aliens that could be building a “megastructure” around the star KIC 8462852 — otherwise known as “Tabby’s Star.”

The recently completed Five-hundred-meter Aperture Spherical radio Telescope, or “FAST,” occupies a valley in the southwestern Guizhou province of China. With a diameter of 500 meters, this monstrous telescope is almost 200 meters wider than the famous Arecibo Observatory in Puerto Rico.

NAIC/Arecibo Observatory, Puerto Rico, USA

And now FAST will join the Breakthrough Listen SETI project to “listen in” on the strange star.

Though the likelihood of actually finding any chatty aliens around the star is slim, great mystery still surrounds the cause of some dramatic dimming events. NASA’s Kepler space telescope recorded these events as transits that caused the star to dip in brightness of up to 22%.

“Planet transit. NASA/Ames

Kepler looks for exoplanets by detecting their transits (i.e. as a planet orbiting another star passes in front, blocking a tiny fraction of starlight). Typically, these transit events block a fraction of one percent of starlight.

NASA/Kepler Telescope

Add to these unprecedented transit events the fact the star has apparently been dimming for over a century, and astronomers have been presented with a quandary: what is blocking the light from Tabby’s Star?

One hypothesis put forward is that the dramatic transits were caused by a cloud of comets, but that explanation has fallen short of proving the source of the anomaly. Most likely is that Tabby’s Star’s weirdness is being caused by some overlooked phenomenon, or a completely new natural phenomenon that has yet to be understood.

But say if the cause isn’t natural? What if there’s an advanced alien civilization building some kind of “Dyson Sphere”-like structure — basically a star-enshrouding solar array that is designed to harness all the star’s energy? Unlikely as it may sound and, as Occam’s Razor dictates, aliens are the least likely explanation, Breakthrough Listen will study the star and it now has a powerful new tool to add to its growing arsenal of radio antennae.

It was announced that FAST would be joining Breakthrough Listen earlier this month, and now it looks like hopes are high that it will be committed specifically to the monitoring of Tabby’s Star despite a busy observing schedule.

“The FAST telescope will be absolutely incredible for conducting extremely sensitive searches of Tabby’s star for evidence of technologically produced radio emissions,” Andrew Siemion, director of the Berkeley SETI Research Center and co-director of Breakthrough Listen, told the South China Morning Post. “We are very excited to work with our colleagues in China on conducting SETI observations with FAST, including of Tabby’s star. Within its frequency range, FAST is the most sensitive telescope in the world capable of conducting SETI observations of Tabby’s star, and will be able to detect the weakest signals.”

Although it’s uncertain when FAST will be joining the effort to study Tabby’s Star — one unnamed source indicated it could be up to two years before FAST will focus on the effort — Beijing Planetarium director Zhu Jin pointed out that it wouldn’t be hard for FAST to participate as the telescope’s very wide viewing angle and individual steerable dish tiles would let it observe Tabby’s Star while carrying out other science.

“Looking at Tabby’s star on FAST will be a very easy thing to do,” said Zhu. “When the telescope was proposed, SETI was listed as a major goal. I don’t think we can turn a blind eye to Tabby’s star.”

See the full article here .

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From Earth Sky: “Astronomers to observe Tabby’s Star”

EarthSky

October 26, 2016
Deborah Byrd

Access mp4 video here .

Beginning tonight (October 26, 2016), and over two more nights more in the coming two months, astronomers will use the Green Bank radio telescope in rural West Virginia to observe Tabby’s Star.

GBO

Tabby herself – astronomer Tabetha Boyajian, formerly of Yale and now at Louisiana State University – will be there to help lead the observations. Her Ted Talk earlier this year created a sensation when she called this star “the most mysterious in the universe.” Beginning tonight, the Breakthrough Listen project at University of California Berkeley is devoting eight hours per night for three nights to observing Tabby’s Star with the Green Bank telescope. The astronomers admit it’s a long-shot, but they want to see if this telescope can detect signals from a possible extraterrestrial civilization that might – or might not – reside on a planet orbiting this star.

It’s the light of this star that has astronomers – and the rest of us – perplexed and interested. Although astronomers have wrangled over the details about Tabby’s Star throughout 2016 – there no denying that its light behaves in a way astronomers have never seen before. It dims for days at a time, by as much as 22 percent, at irregular intervals. Stars do dim, but not in the way this star does, astronomers say.

It appears that something is blocking the light of Tabby’s Star, which, by the way, is officially known as KIC 8462852. Astronomers know that – whatever that something is – it isn’t a planet.

They know that because whatever’s doing the blocking isn’t round and doesn’t appear to orbit the star in a fixed period of time.

Artist’s concept of cascading comets around a distant star. This scenario is one possible explanation for Tabby’s Star. Image via NASA/JPL/Caltech/Vanderbilt University.

An explanation for the strange dimming of Tabby’s Star, the explanation that has everyone so intrigued, is that an alien civilization may be building a megastructure – a Dyson sphere, designed to capture the energy of the star for the civilization’s use – around it.

This possibility is remote, but so far it can’t be dismissed. It’s the reason astronomers just can’t look away.

Andrew Siemion, director of the Berkeley SETI Research Center and co-director of Breakthrough Listen at Berkeley, will also be on hand at Green Bank tonight, helping with the Tabby’s Star observations. He said in a statement:

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. 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.

What can the Green Bank radio telescope bring to the table? Siemion said:

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. 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.

He said the results of the Green Bank observations made tonight will not be known for more than a month, because of the massive data analysis required to pick out patterns in the radio emissions.

Finder chart for Tabby’s Star, aka KIC 8462852. It’s located in the direction to the constellation Cygnus.

By the way, telescope time – and powerful new instruments – cost money, but, in this case, there’s money to be had. Russian internet investor Yuri Milner created the Breakthrough Prize Foundation, which funded Breakthrough Listen in 2015 to the tune of $100 million over 10 years.

Finally, Siemion added that he and his colleagues are skeptical that the star’s unique behavior is a sign of an advanced civilization, but that they just can’t not take a look.

Follow the Berkeley SETI Research Center and Breakthrough Listen via social media: @BerkeleySETI on Twitter, as well as Facebook, Instagram, and YouTube.

Read more via UC Berkeley.

Access mp4 video here .

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From New Scientist: “Triple signal of ‘alien megastructure’ star baffles astronomers”

New Scientist

8 August 2016
Shannon Hall

Comet swarms: just one suggested explanation for strange signals from the “alien megastructure” star. JPL-Caltech/NASA

The mystery of the so-called “alien megastructure” star just deepened.

KIC 8462852, as it is more properly known, flickers so erratically that one astronomer has speculated that nothing other than a massive extraterrestrial construction project could explain its weird behaviour. A further look showed it has been fading for a century. Now, fresh analysis suggests the star has also dimmed more rapidly over the past four years – only adding to the enigma.

“It seems that every time someone looks at the star, it gets weirder and weirder,” says Benjamin Montet at the California Institute of Technology, who led the study.

This space oddity was first spotted by NASA’s Kepler space telescope, which continually monitored 100,000 stars from 2009 to 2013. Any dip observed in a star’s light is a sign that an exoplanet has passed in front of it. These dips, which occur regularly, block at most 1 per cent of the star’s light and have revealed thousands of exoplanets.

But KIC 8462852, also known as Tabby’s star after its discoverer Tabetha Boyajian of Yale University, was an outlier. Its light dipped by as much as 20 per cent and didn’t conform to any regular time intervals – so the signature couldn’t have been caused by a planet.

Astronomers came up with an array of potential explanations, from the mundane to the bizarre. The star made headlines when Jason Wright, an astronomer at Pennsylvania State University, announced that an advanced extraterrestrial civilization could be responsible for the signal.

Curiouser and curiouser

But the plot thickened when Bradley Schaefer, at Louisiana State University in Baton Rouge, probed the star’s behaviour over the past century by looking at old photographic plates from 1890 to 1989. More than 1200 images revealed that Tabby’s star gradually dimmed by as much as 15 per cent over the course of a century.

Schaefer’s work was immediately called into question. However, with so few astronomers who have an expertise in these plates, no one seemed able to settle the debate. That is until Montet and his advisor Josh Simon realised that an answer might be hidden within the Kepler data.

They found that for the first 1000 days of the Kepler mission, Tabby’s star decreased in brightness at roughly 0.34 per cent a year – twice as fast as measured by Schaefer. What’s more, over the next 200 days, the star’s brightness dropped another 2.5 per cent before beginning to level out. It was a much more rapid change than before.

That means the star undergoes three types of dimming: the deep dips that first made it famous, the relatively slow decline observed by Schaefer and verified by Montet and Simon, and the intermediate rapid decline that occurred over a few hundred days.

“We can come up with scenarios that explain one or maybe two of these, but there’s nothing that nicely explains all three,” says Montet.

And the team doesn’t want to resort to creating three separate scenarios. “It would be much more satisfying to think of a single physical cause that could be responsible for all of the brightness variations that we observe,” says Simon. “But we’re still struggling to come up with what that might be.”

And Wright couldn’t be more thrilled. “I was always worried that the mystery would be solved with some really mundane explanation, like some overlooked instrumental effect, and that it would turn out to be a wild goose chase,” he says.

Explanations range from a swarm of comets orbiting the star to an intervening cloud in the interstellar medium – but none fit all the data.

An alien concept

What about that advanced alien megastructure? “Once you’re invoking arbitrary advanced aliens doing something with technology far beyond ours, then there isn’t very much that can’t be explained,” says Simon. “But we don’t really want to resort to that until we exhaust all of the possible natural explanations we can think of.”

Even Wright, the astronomer who postulated the alien megastructure in the first place, admits that it’s a last resort.

In the meantime, astronomers will continue to monitor the star. A successful crowdfunding campaign earlier this year raised over $100,000, allowing astronomers to secure time at the Las Cumbres Observatory Global Telescope Network, where they can observe the star for a year.

The hope is that Tabby’s star will soon drastically dim and they will be able to swing different ground-based and space-based observatories towards it. Catching a transit in as many wavelengths as possible should help pin down what is interfering with the star – be it a swarm of comets, an alien megastructure, or something else entirely.

Reference: http://arxiv.org/abs/1608.01316

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From Discover: “How Astronomers Plan to Solve the Mystery of the ‘Alien Megastructure Star’ “

Discover Magazine

July 31, 2016
Corey S. Powell

In the constellation Cygnus, the faint star formally known as KIC 8462852 displays irregular, enigmatic changes in brightness. Something huge is passing in front of the star and blocking its light–but what? (Credit: Stellaruim, Boyajian et al)

If you look in enough places, eventually you’ll find something profoundly strange. That’s been a reliable rule of thumb through the history of science, and last year it proved dramatically true again for astronomer Tabetha Boyajian. While digging through data from NASA’s Kepler space telescope, which has been monitoring 150,000 stars for signs of orbiting planets, she realized that one of these things is not like the others. A single star in that set, formally catalogued as KIC 8462852 but informally known as Tabby’s Star, flickers in an inexplicable way: unlike the shadows produced by planets, unlike any known type of stellar pulsation, simply unlike anything seen before.

Tabby’s Star is so unusual that a few scientists, including Boyajian’s colleague Jason Wright, raised the possibility that its flickering is not natural but is due to the presence of an enormous artificial construct. That speculation quickly lent KIC 8462852 another nickname, the “alien megastructure star,” and prompted a flood of breathless news stories; it even got a shout out on Saturday Night Live. Boyajian’s subsequent TED lecture drew even more attention to her star.

Now Boyajian, who recently joined the faculty of Louisiana State University, faces the daunting task of sorting through a wide range of potential explanations, from mundane to bizarre. You will probably not be surprised to hear that she’s not a big fan of the space-alien theory, but even the more sober scientific ideas are plenty exotic. I spoke with Boyajian about how she intends to solve her mystery—and about the surprising ways that institutional science is stacked against exploratory research that is not guaranteed to lead to clear answers.

When did you realize you were dealing with something profoundly strange?

There all kinds of glitches that can come up in the data, and you don’t want to spend time on something that’s just a glitch. It’s one of those things that doesn’t excite you right away. To be honest, it was the Planet Hunters [a volunteer citizen science group] who found this. When they pointed it to me, I was like, “The data’s bad, I don’t even want to look at it.” But they said, “We did preliminary tests and it checks out.” I wouldn’t have given KIC 8462852 a second look if it weren’t for that.

Tabetha Boyajian described the story behind the enigmatic “megastructure star” in a TED talk last February. (Credit: TED

Then there were more checks that I did, that other people in my team did, that a few different folks at NASA did, and the Kepler team verified the data as well. It slowly built up into a love-hate relationship, because everything we learned about the star made it more difficult to understand it. Everything we observed made the star look very, very normal [except for its very, very abnormal changes in brightness]. It didn’t resemble any other class of stars that showed any kind of variability. It was a gradual learning process, learning about the star itself and checking out different theories.

What do you do when you are confronted with something like this, a star that seems to defy all the usual scientific explanations?

When you have something that doesn’t fall into any category, you start talking to people. That’s what I did, bouncing ideas off colleagues and testing out different theories. By the time we decided to write up the paper we didn’t really have any results, and this [anomalous behavior] in itself doesn’t really make an exciting paper. The way that scientists are trained, you get some data, you test out theories, you present it in a scientific paper. Writing up something like this that doesn’t have a result, only questions, is very frustrating with that mindset.

We spent a lot of time thinking about KIC 8462852. The idea was to write up everything we learned, every theory we thought of that could try to explain the star, and just present it like that. Which doesn’t make for a very exciting paper, but it is very exciting because this is something brand new. So like I said: love-hate relationship. It’s exciting but it’s frustrating at the same time. We’re looking at a new class of object, for all we know.

The tone of the news reports were not conflicted at all, of course; they were downright giddy, playing up the possibility that we were seeing an alien artifact around a distant star. How did you feel about that response?

I would definitely say it’s been overwhelming. Even in the very good articles that have been written about the star, the title is often leading. Some people don’t do responsible reporting and take it one step further. You know, it is what it is. I didn’t expect this level of excitement at all, but in retrospect I should have!

So is it this? (Credit: Danielle Futselaar/SETI International)

I was surprised that you didn’t approach NASA or some other big agency to help solve the mystery. Why not?

This star needs long-term, continuous monitoring, because there’s no way to predict when something’s going to happen. It’s not periodic. Government facilities don’t have the ability to do long-term monitoring. Public observatories are so well scheduled that you can get maybe three nights in a row; there’s no way to continuously monitor something on a daily basis. You could get government grants to buy time [on a private telescope network], but government grants take a long time. If I wrote a proposal now, and if we actually won, we’d get the money maybe by a year from now. Also, government grants are a very competitive process. There’s no guarantee of success, especially for a proposal like this. We’re looking at one star: high risk, high reward. That’s not something that’s appealing to the National Science Foundation.

What inspired you to launch a Kickstarter campaign? That also surprised me.

Over the past few months–ever since October when the star started being in the spotlight, really–I’ve been getting tons of emails from people asking about how they can contribute. We had a Reddit AMA, and people were offering all kinds of services: “I know nothing about science, but I can do coding work.” They wanted to be involved. Then I gave a TED talk in February, and afterward I got approached by a lot of people interested in contributing. Kickstarter was actually founded by a TED fellow. One thing led to another and this project was born.

The Kickstarter campaign captures the best of all worlds, because it lets the public still be involved. It continues the theme of outreach science, since that’s how the star was discovered. It lets us update the community on how science really works. That’s a positive thing you don’t get through government grants, which are very private.

…or is it this? (Credit: NASA/JPL-Caltech)

So what’s the plan of attack? How will you figure out what the hell is happening around this star?

The plan is to observe the star through a full calendar year at the [private] Las Cumbres Observatory Global Telescope Network (LCOGT).

LCOGT Las Cumbres Observatory Global Telescope Network, Haleakala Hawaii, USA

We have the funds to cover that, and a little bit more. We’re observing now, running off time LCOGT has gifted us, 200 hours there. At the end of the summer, when the Kickstarter funds get transferred, we’ll be able to set up the process through August and probably through December of 2017.

We want to see the star’s brightness dip again—it’s as simple as that. When it dips, how long the dips are, if there are many dips, all of the stuff relevant to any theory that’s on the table. Also, we’ll be able to get more detailed observations of whatever stuff is passing in front of the star, because we have a system to notify us when it’s not at its normal brightness. LCOGT is set up so we can get a spectrum as soon as that trigger happens, and also more intense observations.

Planet transit. NASA/Ames

If it’s not an alien megastructure passing in front of Tabby’s Star, then what is it—and how will you know?

From our new observations, we’ll be able to tell a lot about the material that’s passing in front of the star: if it’s some kind of dusty thing, some kind of solid thing. [Boyajian’s working hypothesis is that the dimming is caused by a huge swarm of comets, set loose perhaps by some cataclysmic event around the star.] What’s also important is that we will also get a baseline of spectral observations so we can look at if there’s any radial velocity shift or if there’s any variable emission of the lines, things we’d expect comets to have.

If the dimming is caused by a transiting family of comets, that would be something completely new. We’ve never seen comets go in front of a star. The dust component of comets is what you’d see in the light curve. What you’d see in the spectral observation is the gas component of comets. It would be very exciting. We’ve never even seen anything like it in our solar system or around another star. We could learn a lot from that.

What kind of signal would tell you that a comet swarm is not the answer, that you need to consider something even more exotic?

We’ll look at the orbital period [as indicated by dimming episodes that repeat]. That might lead us to favor one theory over another. Comets move on very elliptical orbits, though, and if you’re talking about a whole family of comets then individual ones may or may not transit again. That complicates things. The more dips we get the better. If they’re deeper [than what we’ve seen before], if they last longer, any of those observations will help us test out which theory is the right one.

So far, Tabby’s Star seems to be unique. How will we find out if there are others like it, or if this star is really one of a kind?

We’ve searched through the Kepler dataset and we haven’t seen anything like this star, at any level, but Kepler has only looked a little over 0.2% of the sky. There are more surveys coming out that will look at huge amounts of the sky. Now that we have the amazing properties of this one star, will we be able to set up an AI to find another star like this? Or will the next one look completely different? We just don’t know. What we do know is that if we want to find another object similar to this, we’re going to need long-time baseline data. Kepler looked for four years, and the star was doing fun stuff for only a tiny portion of that time.

Well that raises an unsettling thought. What if you observe for a year and nothing happens? What if, by bad luck, you catch the star when it isn’t doing anything interesting?

We’re definitely starting to work that out. The longer we monitor the star, the better chance we have a chance to catch new details. Maybe we need something set up for the next 10 years! It’s going to take more work. The LCOGT observatory is working with us, and if we need to do another Kickstarter that can happen, even though it’s a lot of work. It’s a nail-biter.

It seems like there should be a way to carry out this kind of purely exploratory research without having to resort to Kickstarter or the like. What do you think?

Just to be clear, we have the support of tons of astronomers. Kickstarter doesn’t have to be peer reviewed, but nobody has said, this is bullshit, you can’t do that, you should be doing science. Everybody understands our point of view. The peer review process works really well overall, but it [isn’t appropriate when] the probability of having results at the end of the year is very low. Having a different, government-funded channel for scientists to do higher-risk proposals would definitely allow a lot of other cool science to get done.

See the full article here .

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