A Jupiter size planet has blocks 1% of a Stars light, but this has some dips of 15% and 22% and hundreds of other non periodic smaller dips.
KIC 8462852 is a star somewhat more massive, hotter, and brighter than the Sun.
It is 1480 light-years away. The Kepler data for the star are pretty bizarre: There are dips in the light, but they aren’t periodic. They can be very deep; one dropped the amount of starlight by 15 percent, and another by a whopping 22 percent.
Straight away, we know we’re not dealing with a planet. Even a Jupiter-sized planet only blocks roughly 1 percent of this kind of star’s light, and that’s about as big as a planet gets. It can’t be due to a star, either; we’d see it if it were. And the lack of a regular, repeating signal belies both of these as well. Whatever is blocking the star is big, though, up to half the width of the star itself.
There are lots of these dips in the star’s light. Hundreds. And they don’t seem to be periodic at all. They have odd shapes to them, too. A planet blocking a star’s light will have a generally symmetric dip; the light fades a little, remains steady at that level, then goes back up later. The dip at 800 days in the KIC 8462852 data doesn’t do that; it drops slowly, then rises more rapidly. Another one at 1,500 days has a series of blips up and down inside the main dips. There’s also an apparent change in brightness that seems to go up and down roughly every 20 days for weeks, then disappears completely. It’s likely just random transits, but still. It’s bizarre.
Comets are a good guess, but it’s hard to imagine a scenario where they could completely block 22 percent of the light from a star; that’s a huge amount. Really huge.
What is a Dyson Swarm ?
A Dyson Swarm has the function of a Dyson sphere to collect most solar energy, but a Dyson swarm can be built with reasonably near term materials and technology while a Dyson Sphere needs materials beyond carbon nanotubes.
A "Dyson swarm" consists of a large number of independent constructs (usually solar power satellites and space habitats) orbiting in a dense formation around the star. This construction approach has advantages: components could be sized appropriately, and it can be constructed incrementally. Various forms of wireless energy transfer could be used to transfer energy between components and Earth. It is the most technically feasible method of gathering most of the power from a star.
Three astronomers want to point a radio dish at the star to look for wavelengths associated with technological civilisations. And the first observations could be ready to take place as early as January, with follow-up observations potentially coming even quicker.