# Why are scientists considering the ETI explanation for Tabby's star?

When Yale astronomer Tabetha Boyajian located star KIC 8462852 ("Tabby’s star"), some U.S. scientists proposed artificial megastructure(s), such as a Dyson sphere/swarm, instead of discussing more likely explanations.

Tabetha is also found giving a talk on TEDx in which she presents:

Something massive, with roughly 1,000 times the area of Earth, is blocking the light coming from a distant star known as KIC 8462852, and nobody is quite sure what it is. As astronomer Tabetha Boyajian investigated this perplexing celestial object, a colleague suggested something unusual: Could it be an alien-built megastructure?

It is amazing to see how these U.S. scientists proposed completely unusual and insignificant theory which attracts people's attention.

Usually, it is expected that a scientist proposes some reasonable theory instead of science fiction because they are utilizing tax money.

Normally, this type of arugement is supported by Drake Equation:

The Drake equation is: $$N$$ = $$R$$ ∗ ⋅$$f_{_p}$$$$n_{_e}$$$$f_{_l}$$$$f_{_i}$$$$f_{_c}$$$$L$$

where:

N = the number of civilizations in our galaxy with which communication might be possible (i.e. which are on our current past light cone); and

R∗ = the average rate of star formation in our galaxy

$$f_{_p}$$ = the fraction of those stars that have planets

$$n_{_e}$$ = the average number of planets that can potentially support life per star that has planets

$$f_{_l}$$ = the fraction of planets that could support life that actually develop life at some point

$$f_{_i}$$ = the fraction of planets with life that actually go on to develop intelligent life (civilizations)

$$f_{_c}$$ = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space

$$L$$ = the length of time for which such civilizations release detectable signals into space

I believe the Drake Theory is entirely based on preposterous arguments. Anyone can come up with such an equation and you can't counter or argue it because they say it is a probabilistic argument. Out of 7 variables given on R.H.S there are 6 variables which are utterly unverifiable.

Disclaimer: I have presented the facts best know to me. Here I have not presented an iota of speculation or my personal thoughts.

• What’s your evidence that US scientists are more inclined toward artificial/alien explanations than natural ones? Simply advancing the hypothesis doesn’t mean they think it’s the most likely explanation. Jul 22, 2018 at 13:49
• I've voted to re-open this question, and reversed my vote to "up". I think there are some really important space exploration issues addressed here (that apply equally to exploration of solar-system and extra-solar phenomenon) and I'd like the opportunity to demonstrate this by posting an answer, as well as issues about interaction between science and the public. I've also done some comment cleanup. Once issues are resolved, it's always appreciated when comments that have served their purpose are removed, so that the focus remains on the questions and their answers.
– uhoh
Jul 23, 2018 at 1:15
• Comments are not for extended discussion; this conversation has been moved to chat. Jul 23, 2018 at 11:30
• Better question is why does this person think that 1 scientist's speculation somehow represents an entire nations accepted outlook.
– anon
Jul 23, 2018 at 11:32
• "t is amazing to see how U.S. scientists are allowed to direct thoughts towards a completely unusual and insignificant theory which attracts people's attention. " You present no evidence that more than one scientist does this. Also, there are no rules anywhere that I know of concerning where people are allowed to direct their thoughts. Jul 23, 2018 at 13:35

Edit: added some more details on the scientific method.

KIC 8462852 is unusual. It exhibits dimming, but unlike other variable stars this dimming follows an irregular pattern.

Several hypotheses have been proposed to explain the star's large irregular changes in brightness as measured by its light curve, but none to date fully explain all aspects of the curve. One explanation is that an "uneven ring of dust" orbits KIC 8462852.[8][9][10][11][12][13] In another explanation, the star's luminosity is modulated by changes in the efficiency of heat transport to its photosphere, so no external obscuration is required.[14] A third hypothesis, based on a lack of observed infrared light, posits a swarm of cold, dusty comet fragments in a highly eccentric orbit,[15][16][17] however, the notion that disturbed comets from such a cloud could exist in high enough numbers to obscure 22% of the star's observed luminosity has been doubted.[18] Another hypothesis is that a large number of small masses in "tight formation" are orbiting the star.[6] Furthermore, spectroscopic study of the system has found no evidence for coalescing material or hot close-in dust or circumstellar matter from an evaporating or exploding planet within a few astronomical units of the mature central star.[15][19]

So scientists first tried to find natural phenomena that could explain the dimming. Using e.g. Occam's razor, scientists go with the simplest, most likely explanation first, and move on to more complex hypotheses only if the simple one does not match the observations.

When those hypotheses all failed to fully explain the irregular light curve, some scientists suggested we might be looking at a Dyson sphere being built.

It has also been hypothesized that the changes in brightness could be signs of activity associated with intelligent extraterrestrial life constructing a Dyson swarm.[6][20] The scientists involved are very skeptical, however, with others describing it as implausible.[18][21]

This is exactly how science is supposed to work.

In this case, the question is the dimming pattern of KIC 8462852. How can we explain the irregularities in that pattern?

From earlier observations of other stars, and the theoretical work that underpins them we have a series of possible causes for star dimming. These are our hypotheses.

Then you conduct tests (or calculations, simulations etc.) to see if your hypotheses match the observations.

When the hypothesis can explain everything in your observation, good. When it can't, that's one hypothesis you have to discard (at least for the time being). In the mean time, you try to get more observations so you can add more detail to your knowledge of the system.

In this case, there are several astrophysical phenomena that can explain dimming to some extent. Because these astrophysical phenomena all follow the laws of physics, you can calculate how they will behave and determine their limits. E.g. orbits are regular, so a planet obscuring part of its star will do so in a predictable pattern.

The team studying this star tested all known astrophysical phenomena and found that none of them are a good match for the observations. That's when it's time to formulate new hypotheses: is this something we've never seen before? If so, how is it caused? Can we find a physical process that causes this? Or do we have to conclude whatever's causing the dimming isn't caused by natural processes?

Note that these are just hypotheses, and will be analyzed the same way the original ones were. Nobody's saying "it must be aliens", they're saying, "we've run out of natural phenomena that can cause this, maybe something unknown is at work here".

It is amazing to see how U.S. scientists are allowed to direct thoughts towards a completely unusual and insignificant theory which attracts people's attention.

Attracting attention (and thus funding) is one possible way of looking at what happened. Another way is this: these scientists were going where the evidence took them.

The phrase "how U.S. scientists are allowed" is a dangerous one. One of the foundations of science is academic freedom: the freedom to think and say what you want without having to fear censorship. Censorship is a death sentence for science: how can progress be made if scientists can't discuss hypotheses that seem unlikely or offensive?
The world learned this the hard way through the centuries (Galilei's treatment is one example of how not to treat a scientist).

Dismissing a hypothesis out of hand by calling it 'unusual and insignificant' is not science. We've never found definitive proof that intelligent aliens exist, but we've found no proof that they don't exist either. We've only been looking for a few decades, so our sample size is very small compared to the 100 billion stars in our galaxy. That makes 'aliens' a valid hypothesis. It's unfortunate that this hypothesis attracts so much attention and nonsense, but that's no reason to discount the hypothesis.

Normally, this type of argument is supported by Drake Equation:

No it isn't. As you've found, at the moment, most of the terms in that equation can't be given a number with any certainty, we just don't know enough at the moment. We've only started finding extrasolar planets a few decades ago, and there still are many planets too small to see with current detection methods. The other terms are even harder to quantify. So Drake's equation is little more than a thought experiment, and not a basis on which we can build anything. So, you won't find scientists using it for that.

• @Hobbes "This is exactly how science is supposed to work."??? then why UFO sighting and alien abduction theories are mocked (I don't support these either), but just for science sake they should have accepted 1 out of so many UFO encounters. Isn't it? Jul 23, 2018 at 14:39
• @Looper UFO's haven't been scientifically disproven, they are mocked usually because of the religious zeal enthusiasts pursue in that explanation in lieu of facts and other possibilities. Bare in mind SETI has been funded for decades, so UFO's arent in the same bucket as witchcraft.
– anon
Jul 23, 2018 at 14:46
• @Looper I don't know what "pure" science you speak of that outright rejects possibilities without facts, frankly I'm glad we have moved passed the dark ages. But reality is, science progresses very slowly without money. The ISS wasn't built on hope and best wishes.
– anon
Jul 23, 2018 at 14:54
• @Looper: UFOs and alien abduction stories are mocked when they're presented (as they often are) without any supporting evidence. After hundreds of 'UFOs' that turned out to be insects, clouds or lens flares the scientific community is understandably sceptical when the next one is presented. Jul 23, 2018 at 15:26
• @Looper - Here's a big gap between Tabby's Star and UFOs. Tabby's Star is a series of unexplainable observations, and aliens are one theory presented to explain them. UFO sightings are a series of unconfirmed anecdotes, so proposing an alien theory is premature - we haven't agreed that the phenomenon even exists to begin proposing theories of origin/cause. Jul 23, 2018 at 16:45