Mystery of the 'alien megastructure' SOLVED? Bizarre object is more likely to be a lopsided star than a Dyson sphere.

A curious star more than 1,400 light-years from Earth has completely baffled astronomers.
It's so unlike anything we've ever seen, scientists can't entirely discount that it's evidence of an alien civilization.
The star, called KIC 8462852, is so distant the only information we have about it comes from its light curves — the amount of light from the star that makes it back to Earth.
Astronomers have noticed strange blobs around the star blocking out some of its light. The blobs don't seem to be planets because they follow a random pattern rather than a predictable, planet-like orbit.
A giant swarm of comets or a broken-up planet might cause the strange phenomenon, but no particularly convincing astronomical explanations have emerged. That's why some believe the weird blobs might be a Dyson sphere — an enormous group of solar panels orbiting a star to harvest its energy — therefore implying that we may be observing a technological "megastructure" built by aliens.
As Penn State astronomer Kimberly Cartier told Business Insider, however, the media coverage has "gotten a bit out of hand."
Tech Insider has spotted what we think is the best explanation yet for KIC 8462852, and it doesn't involve aliens at all.
Jim Galasyn, a writer for the blog Desdemona Despair, saw a 2013 research paper posted by commenter "Michael" on a story from Centauri Dreams. That paper explains how some stars don't have a uniform brightness level because they're irregularly shaped and "oblate" discs.
As the researchers write in that study:

When a star is oblate, it has a larger radius at its equator than it does at its poles. As a result, the poles have a higher surface gravity, and thus higher temperature and brightness. Thus, the poles are "gravity brightened", and the equator "gravity darkened."
The star becomes oblate (and hence gravity darkening occurs) because the centrifugal force resulting from rotation creates additional outward pressure on the star.

This creates patches of darker and lighter regions within these kinds of stars, so the light curves that make it back to Earth won't look completely uniform. What's more, planets often orbit "obliquely" from Earth's perspective and do not pass directly in front of a star.
So those especially weird light curves from KIC 8462852 could easily be caused by planets passing in front of darker and lighter regions — not alien artifacts floating around it.
In the image from the research paper below, the red sphere represents an oblate star, and the smaller circles illustrate the path that a planet might take around the star. As the planet crosses into darker and lighter patches of the star, it creates the abnormal light curves that you can see below:
Barnes et al/The Astrophysical Journal
For comparison, here is a light curve from KIC 8462852:
T.S. Boyajian et al./arXiv.orgLight intensity (left) and days of observation (bottom) show how KIC 8462852's light fluctuates over time.
Our overlay of both graphics (below), inspired by one of Galasyn's illustrations, isn't scientific. However, it shows how an oblate star and planets orbiting it would better explain the light curves:
T.S. Boyajian et al. (arXiv.org)/J.W. Barnes et al. (The Astrophysical Journal)/Tech Insider
This seems like a more likely explanation than aliens, but just in case it's off, the Search for Extraterrestrial Intelligence (SETI) Institute, an organization that searches for signs of life beyond Earth, is still closely examining the star.
Researchers there have been pointing the ground-based Allen Telescope Array in California at the bizarre star for the past several days.
SETI researcher Doug Vakoch told Business Insider that we should know if it's aliens within the next week or so.

"We are looking at it with the Allen Telescope Array," Seth Shostak, a senior astronomer at the SETI (Search for Extraterrestrial Intelligence) Institute in the US told Mike Wall at Space.com. "I think we ought to, for sure," he added, but said we should prepare ourselves to be disappointed, because newsflash: it’s probably not actually aliens. "[people] should perhaps moderate their enthusiasm with the lessons of history", he said.

But whatever is causing these seriously strange dips in brightness around KIC 8462852 will still make for some fascinating research, because it's defied any reasonable explanation so far. The most obvious explanation is a colossal dust cloud, but scientists have ruled this out as unlikely because space dust gives off infrared light, and no excess of infrared light has been detected around the star. 

So a swarm of comets then? In this scenario, another star passed into KIC 8462852's system and the disturbance of gravity caused a huge mass of comets to be pulled in towards it before being expelled back out again. And there just so happens to be another star close enough to KIC 8462852 to make this a possibility. 

But as we explained last week, we would have had to have been extraordinarily lucky to witness this specific event in cosmic history, which brings its likelihood into question too.

And, of course, the most fun explanation for that giant shadow is the beginnings of an enormous floating structure being built by an advanced alien civilisation. We can dream, right? 

The Allen Telescope Array won’t be looking at the brightness dips around KIC 8462852, but will instead be listening out for radio signals emanating from the vicinity, which are considered to be a good indication of international broadcasts. SETI Institute researcher Doug Vakoch told Alan Boyle at Geekwire that it’s currently analysing KIC 8462852’s radio signals in 9 billion channels, over wavelengths ranging from 1 to 10 GHz. "We hop along one hertz at a time … focusing on a search for narrowband signals," he said.

If the ATA picks up anything of note, the SETI researchers hope to follow up with the Very Large Array (VLA) near Socorro in New Mexico, Deborah Byrd reports for Earthsky.org. And they hopefully won't be the only ones investigating the mystery of everyone’s new favourite star. The team that discovered those "crazy light curves" is right now making a pitch to have big radio dishes like the VLA or the Green Bank Telescope in West Virginia trained in on the star.

In the meantime, be sure to check out this account of the discovery by Jason Wright, the Penn State astronomer who made the original "aliens?!" comment. It’s a fascinating look into what he and his colleagues have experienced so far, and gives a really interesting insight into how SETI researchers decide what to focus their attention and resources on.

As Wright says, it's probably - almost definitely - not aliens, but it's still in SETI's interest to investigate as-yet-unexplained cosmic phenomena such as this:

"One should focus one’s resources on the best targets. Looking for astronomical anomalies is a reasonable way to focus one’s search. There is no inconsistency between assuming purely natural explanations for all phenomena, and targeting SETI efforts at the most astrophysically inexplicable phenomena."

We can't wait to see what they find. Watch this space.