Let’s talk about the catchily named KIC 8462852. The star has got the scientific community all in a tizzy again by getting dim. Some think it’s obscured by something else, maybe another star but others have theorised that an alien megastructure is what is causing the anomaly.
Amateur astronomers have had their telescopes trained on the object to witness the, as yet, unexplained phenomena. For the uninitiated back in 2015 scientists noticed that this little star was flashing at us, well sort of. By that I mean it was experiencing large dips in its brightness.
Reasons for dimming
There are two potential reasons for these dips in brightness. The first is that there is something in front of it that is blocking its light and therefore making it appear dimmer than it actually is. The second is that there is some kind of process going on within the star causing it to actually dim. Think of it like a breeze interfering with a candle.
The star has the nickname Tabby’s star – hold on a minute, why can’t that just be its actual name? It received that moniker having been extensively studied by Dr Tabetha Boyajian. Scientists and the public alike have a wide range of theories on the causes of the dimming.
Perhaps the most famous of these theories is the idea that there is some kind of Megastructure surrounding the astral body. Similar to a Dyson sphere, a hypothetical structure that surrounds a star and “sucks up” its power.
Sci-fi writers have incorporated a Dyson Sphere into many of their works. The idea was popularised by Olaf Stapledon who came up with the concept in his book entitled: Star Maker. It was later studied by Freeman Dyson, hence the name. He wrote a paper on the subject entitled: Search for Artificial Stellar Sources of Infrared Radiation.
However, SETI has somewhat debunked this theory. They have focused their telescopes on the area and haven’t found any signals that suggest there is any kind of machinery in the area.
There are other theories that have gained popularity only to be shot down Such as the idea that a big bunch of comets sat in front of the star and caused the obstruction (hence the dimming). Of course, they eventually disintegrated.
That explains why it dimmed and then got brighter. Unfortunately, it doesn’t explain why the process seems to have repeated itself. Photographic evidence suggests it’s been doing it since at least 1890!
That could be the answer, but in order for that to be true, it would require about 648000 comets, all bigger than 125 miles across! Of course, that could happen. In an infinite universe, there are infinite possibilities! But it’s pretty unlikely.
Then there is the theory that Tabby’s star might be a variable star. There are two types of these. Firstly there’s a “pulsating variable” these stars grow and shrink quite dramatically. And there are “eclipsing binaries” these appear to shrink when a close by star moves in front of it.
Interestingly our own sun is actually an example of this. It dims by 0.1 per cent every 11 years.
The problem with this theory is that Tabby’s star is an F-Type star. These are stars that are very stable. Meaning that only a small change in brightness should ever be seen. But this star’s brightness has changed by 3 percent in just over 4 years.
There are other theories that have come and gone through the years. Some people have suggested that KIC8462852 is “consuming a planet”, some have hypothesised that there is a large dust cloud that obscures it making it appear dimmer but these have all fallen by the wayside.