21 Oct 2015

Are megastructures a mad idea?

2:29 pm on 21 October 2015

What are these alien megastructures of which you speak?

According to one hypothesis, a swarm of alien megastructures may have been assembled around KIC 8462852.

Wow. And what is KIC 8462852?

KIC 8462852 is a star, in the direction of the northern constellation of Cygnus, a very, very long way away.

Wow. Why might it be home to an alien megastructure?

It's all about the flickering.

The flickering? Wow.

Data returned by Nasa's Kepler Space Telescope reveals a unique light pattern emitted by the star. Unlike the other 150,000 or so stars monitored by the telescope the light flickered and dimmed so dramatically it couldn't be some bog-standard orbiting planet. And not only that: the intervals appear to be utterly irregular.

OK. Still waiting to hear about the alien megastructures.

The light patterns are the sort of thing you might expect to see produced by a "swarm of megastructures", reckons Jason Wright, an astronomer from Penn State University. The data struck him as "crazy", he told the Atlantic. "Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilisation to build."

For the last time: what are alien megastructure?

Elaborate constructions that soak up energy from a star - something like a massive set of solar panel clusters - not unlike a Dyson Sphere.

A Dyson Sphere?

The Dyson Sphere is a hypothetical concept, popularised by the acclaimed physicist Freeman Dyson, describing a structure that might encircle a star, so capturing just about all of its energy. Dyson postulated that advanced civilisations, requiring energy sources for survival, may endeavour to create these megastructures; and were humans to identify such things it could offer a clue to the existence of intelligent life, or aliens.

No. Probably not. Let's just say no.

Is the Lorde song Yellow Flicker Beat about alien megastructures?

No, it's about Katniss Everdeen, lead character in The Hunger Games. But some people on the internet do think Lorde is an extra-terrestrial and when you think about it she's a New Zealander and this article appears on a New Zealand website, so there's definitely something suspicious about the whole business.

Why did Wright start chasing this star?

He was alerted by Tabetha Boyajian, a postdoctoral fellow at Yale, who has co-authored a paper about the star with colleagues. She considered a range of explanations, such as: what if it is simply great wads of mass orbiting close to the star, much like our solar system in its infancy, before gravity organised it into shape?

That sounds persuasive. What about it?

This star is not young. If it was young there'd be a shell of dust emitting oodles of infrared light. There isn't. Obviously.

What then did Boyajian conclude?

That "the scenario most consistent with the data is the passage of a family of exocomet fragments, all of which are associated with a single previous breakup event".

The what, now?

A group of comets might have been re-routed by another interfering star, hurling swarms of ice and rock towards KIC 8462852. It would be quite a coincidence for this to have taken place in the small period of observation, but it's plausible.

So there's no need for wild alien theories after all.

Boyajian's approach specifically proscribed considering non "natural" explanations, but no. Alien megastructures is an almighty long shot.

How was the star identified?

It was discovered via Planet Hunters, a crowd-source programme overseen by Boyajian. Kepler data on the brightness patterns of some 150,000 stars is examined by volunteers. Typically they're looking for information suggesting a planet is in the neighbourhood.

How up to date is our information?

The star was identified as a bit special in 2011, but data was recorded between 2009 and 2013.

So we don't know what's gone on up there since 2013?

We don't know what's gone on up there since the middle of the sixth century. The star is about 1,481 light-years from Earth.

What next?

Wright, Boyajian and someone from the US SETI (search for extraterrestrial intelligence) Research Centre are hoping to train a radio dish on the star, to see whether it is issuing radio waves at frequencies consistent with technological activity. If that goes well, then they want to try with the Very Large Array, situated in New Mexico, in the hope of identifying more about the source.

Isn't the whole quest to find aliens self-indulgent and silly?

You may think so. But it's taken seriously by plenty of top scientists.

Like whom?

In launching a new $100 million project earlier this year, Stephen Hawking said, "Somewhere in the cosmos, perhaps intelligent life might be watching these lights of ours, aware of what they mean. Or do our lights wander a lifeless cosmos, unseen beacons announcing that, here on one rock, the universe discovered its existence? Either way, there is no better question. It's time to commit to finding the answer, to search for life beyond Earth."

Wow. Sum it up in 25 earthly words.

Invisible to the naked eye, a distant flickering light makes mystery. Might it be giant solar panels built by aliens? Very, very unlikely. And yet.

And in five words?

KIC 8462852 is Out There.

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*This column is part of a weekly series, which is published every Wednesday, by graphic artist Toby Morris and journalist Toby Manhire.