Astronomy can occasionally be like high school. New discoveries spark curiosity and debate that sometimes can get ahead of itself, especially when the media gets involved. This past week has been the perfect example. In case you haven’t heard, the story goes like this: Scientists have found a new star and it’s weird. So weird in fact that one of the few explanations they are still considering to explain what is going on is that there might be an alien megastructure built around it.
Before we get too far into this, I want to point out that I am using the word “new” as in “we are now pay attention to this star.” It has always been in existence, minding its own business, 1500 light years from Earth. The star is named KIC 8462852, but for the sake of simplicity and a decent metaphor let’s call it Clint.
Clint is the kid who shows up for the first day of grade 12 and immediately catches everyone’s eye. He doesn’t dress like anyone else, doesn’t follow the same rules as everyone else, and doesn’t care that you can’t figure him out. He is mysterious, but you don’t know if he’s cool or just disturbed. Clint might even be a dork who goes home and plays with slide rulers all night, we just don’t know.
In real terms, the star we’re calling Clint is interesting because of what is going on around it. As you might recall from our discussion of exoplanets, astronomers detect planets outside our solar system by watching the light from distant stars. When a planet passes in front of a star, the light dims slightly. From this dimming, smart folks can work out the size, composition, location, and sometimes colour of the planet in question.
The problem with Clint, is that the dimming we’re seeing just doesn’t make sense. The thing with planets, is that they are generally pretty insignificant compared to their stars. As we learned in Sketchy Fact #100, over a million Earths could fit inside the Sun. The upshot is that even massive planets like Jupiter only block about 1% of their star’s light when they pass in front of it. However, scientists watching Clint have seen drops by as much as 22%! To understand how crazy that is, imagine being at the beach when a cloud moves in front of the sun and blocks a quarter of its light. The difference it makes is enough to make you want to layer up.
The other thing about the dimming of Clint (dibs on that album name) is that it is unpredictable. Planets orbit their stars at regular intervals. If you were watching the Earth pass in front of the Sun, you could reliably say that there will be a 365 day gap between so-called “transits.” Clint on the other hand is being blocked seemingly at random, and really frequently. Scientists have observed hundreds of dips in the light we’re receiving that indicate objects of all shapes and sizes. So what is going on?
Well, we are pretty sure we know what it isn’t. It’s not a problem with the Keplar space telescope that has been collecting the data and it’s not due to starspots (natural formation on the surface of a star that impact the light it gives off. It also probably isn’t a dust cloud caused by a collision between objects orbiting the star. Dust clouds of that sort gather and radiate infrared light, and that isn’t happening with Clint. So what is left?
There are two main theories astronomers are working with at this point:
1 Theory 1: It could be comets. It turns out there is another star that is relatively close to Clint. This star’s gravity could be disturbing Clint’s Oort cloud (most stars have a cloud of icy objects like comets in the far reaches of their solar systems.). If the neighbouring star passes close enough it could cause comets to fall into the inner solar system. As these comets melt they would release dust and occasionally explode, explaining the unpredictable nature of the dimming. In this case, it would be weird not to see excess infrared light, but not completely ridiculous since comets are made up of a lot more than just dust.
Theory 2: It might, slightly, possibly, potentially could be aliens. I know, I know. Most people are either going to laugh that off or accuse me of getting their hopes up. But the pattern of dimming the researchers are seeing is what you would expect if an alien civilization built a megastructure like an array of solar panels around their star to generate clean, reliable energy.
The next few months will tell us more as scientists use the massive radio telescopes we have on Earth to try and detect radio signals coming from Clint’s system. They are expecting more data as early as January.
In the meantime, we’ll just have to sit in science class with pondersome looks on our faces as we try to figure out if we should give Clint a wedgie or ask him to prom.