extraterrestrial intelligence

sk-2017_04_article_main_desktop — Sadly, not aliens (NASA/Getty/Ian O’Neill)

If you were hoping that the bizarre transit signals coming from Tabby’s Star were signs of a massive alien construction site, you’d better sit down.

A new study published in Astrophysical Journal Letters today documents a highly-detailed astronomical study of the star, concluding that this stellar oddity is driven by natural phenomena and most likely not caused by an extraterrestrial intelligence.

Since citizen scientists of the exoplanet project Planet Hunters identified the odd transit signal of KIC 8462852 from publicly-available data collected by NASA’s Kepler Space Telescope in 2015, the world has been captivated by what it means. Though KIC 8462852 is a fairly average star as stars go, it exhibited inexplicable dimming events that have never been seen before.

Finding something extraordinary in deep space is often followed by extraordinary explanations, including the possibility that some super-advanced alien civilization is building a “megastructure” around its star. Over time, more rational hypotheses have been ruled out, but how do you rule out aliens fiddling with their star’s brightness? Well, that’s taken a little more time.

Now, thanks to a study headed by astronomer Tabetha Boyajian of Louisiana State University in Baton Rouge, it seems the alien megastructure hypothesis has bitten the dust, literally.

“Dust is most likely the reason why the star’s light appears to dim and brighten,” Boyajian said in a statement. “The new data shows that different colors of light are being blocked at different intensities. Therefore, whatever is passing between us and the star is not opaque, as would be expected from a planet or alien megastructure.”

As you’d expect, if something solid (like a massive Alien Made™ solar energy collector) were to pass in front of a star, all wavelengths of light would be stopped at the same time. The fact that the dimming events are wavelength (brightness) dependent suggests that whatever is blocking the starlight isn’t a solid mass.

Boyajian, Tabby’s Star’s namesake who led the team that discovered the stellar dimming phenomenon, and her team of over 100 astronomers carried out an unprecedented observation campaign on the star from March 2016 to December 2017 using the Las Cumbres Observatory network. The project was supported by a Kickstarter campaign that raised $100,000 from 1,700 backers.

During the campaign, four distinct dimming events were detected at Tabby’s Star and each were given names by the project’s crowdfunding community. Starting in May 2017, the first two dips were named “Elsie” and “Celeste,” and the second two were named after the lost cities of Scotland’s “Scara Brae” and Cambodia’s “Angkor.”

“They’re ancient; we are watching things that happened more than 1,000 years ago. They’re almost certainly caused by something ordinary, at least on a cosmic scale. And yet that makes them more interesting, not less. But most of all, they’re mysterious.” — from “The First Post-Kepler Brightness Dips of KIC 8462852,” ApJL, 2018

Although the story of the alien megastructure may be coming to an end, this astronomical saga has been an incredible success for science outreach and public engagement with citizen science projects, like Planet Hunters. In this incredible age of astronomy where there’s simply too much data to analyse, scientists are increasingly turning to the public for help in making groundbreaking discoveries.

“If it wasn’t for people with an unbiased look on our universe, this unusual star would have been overlooked,” added Boyajian. “Again, without the public support for this dedicated observing run, we would not have this large amount of data.”

So, the search continues and I, for one, am excited for the next “alien megastructure” mystery …

It’s an “out there” hypothesis, but radiation from alien spacecraft zooming around space could account for the strange bursts of radio waves coming randomly from the deep cosmos.

Powerful bursts of radio waves have been observed at random all over the sky and astronomers are having a hard time figuring out what the heck could be causing them. Many natural phenomena have been put forward as candidates — from massive stellar explosions to neutron star collisions — but none seem to fit the bill. It’s a mystery in its purest sense.

Pulling the alien card will likely raise some eyebrows in some academic circles, but if these so-called fast radio bursts (FRBs for short) end up lacking a satisfactory explanation, according to Avi Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA), an artificial source (e.g. advanced extraterrestrial intelligence) could become the prime suspect.

“Fast radio bursts are exceedingly bright given their short duration and origin at great distances, and we haven’t identified a possible natural source with any confidence,” said Loeb in a statement. “An artificial origin is worth contemplating and checking.”

FRBs are super weird. First detected in 2007, several radio observatories on Earth — including the famous Arecibo Observatory in Puerto Rico and the Parkes Observatory in Australia — have serendipitously detected only a couple of dozen events. And they are powerful; in a fraction of a second, they erupt with as much energy as our sun pumps out in 10,000 years. These are lucky detections as they only occur when the radio dishes just happen to be pointing at the right place at the right time. Astronomers predict there could be thousands of FRB events across the entire sky every single day. There seems to be no pattern, they appear to originate from distant galaxies billions of light-years away and they have no known progenitor.

So far, FRBs have been mainly identified from looking back through historic radio data, but now, the Parkes Observatory has a real-time FRB detection system that will alert astronomers of their detection, allowing rapid follow-up investigations of source regions. This system resulted in a breakthrough last year when astronomers were able to work out that one FRB originated in an old elliptical galaxy some six billion light-years away. This single event helped researchers narrow down FRB sources — as the galaxy is old and exhibits little star formation processes, some production mechanisms could be ruled out (or at least determined to be less likely).

“This is not what we expected,” said Simon Johnston, Head of Astrophysics at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) which manages Parkes, at the time. “It might mean that the FRB resulted from, say, two neutron stars colliding rather than anything to do with recent star birth.”

But say if the source is a little more, well, alien; why would extraterrestrial intelligence(s) be blasting this incredibly powerful radiation into space in the first place?

In their research to be published in Astrophysical Journal Letters, Loeb and co-investigator Manasvi Lingam of Harvard University looked at a form of beamed energy that could be used to propel interstellar probes to the stars. Vast planet-sized solar receivers could collect the required energy and the power collected could be transferred into a laser-like device that is bigger than we can currently imagine. Although the technology required to create such a device is in the realms of science-fiction, according to the researchers’ work, it’s not beyond the realms of physics.

This hypothetical mega-laser could then be used to blast a huge solarsail-like spacecraft across interstellar — perhaps even intergalactic — distances. The photon pressure exerted by this kind of propulsion technique could accelerate spacecraft of a million tons to relativistic speeds. The engineering details of such a device are only known to these advanced hypothetical aliens, however.

Like this… kinda. (Credit: Walt Disney Studios Motion Pictures)

This form of beamed energy would need to be continuously aimed at the departing spacecraft, like a dandelion seed being constantly blown through the air by a steady breeze, to help it accelerate sufficiently to its desired destination — so why would such a technology manifest itself on Earth as a mere radio flash in the sky? Well, to keep the beamed energy on target (i.e. centered on the spacecraft’s sail), it will remain fixed on the spacecraft. But the spacecraft, planet and star will all be moving relative to us, sweeping the beam across the sky, so the beam will only briefly appear in our skies and then disappear as a random FRB. Even if there’s a permanent “beamed energy station” continuously firing spacecraft into deep space, we may only ever see one flash from that location — space is a big place, we’d need to lie directly in the firing line (over millions to billions of light-years away) for us to even glimpse it.

And if these FRBs are originating all over the sky, from many different stars in many different galaxies, it could mean that this beamed propulsion technology is a natural progression for sufficiently advanced civilizations. We could be in the middle of a vast intergalactic transportation network that we can only join when we are sufficiently advanced ourselves to build our own beamed energy station — like an intergalactic bus stop. Mind-bending stuff, right?

Alternatively, FRBs could just be a natural phenomena that our current understanding of the universe cannot explain, but it’s good to investigate all avenues, scientifically.

“Science isn’t a matter of belief, it’s a matter of evidence. Deciding what’s likely ahead of time limits the possibilities. It’s worth putting ideas out there and letting the data be the judge,” concludes Loeb.

And you know what? I couldn’t agree more.

Tag: extraterrestrial intelligence

Tabby’s Star Dust-Up: There’s No Alien Megastructure

Could Alien Spacecraft Propulsion Explain the Cosmic Mystery of Fast Radio Bursts?

It’s an “out there” hypothesis, but radiation from alien spacecraft zooming around space could account for the strange bursts of radio waves coming randomly from the deep cosmos.