re: Alien megastructures? SETI Institute’s Allen Telescope Array targets weird star.

quote:

---

There is no way variability of the companion (star) can make an impression on KIC 8462852’s light curve at the observed level.

---

We don't have a lot of info about the companion star except that it's small and ~93 billion miles (1,000 AU) from KIC 8462852. One AU is ~93 million miles.

93 billion miles is extremely close by astronomical measurements but is it close enough to disrupt the orbits of other bodies circling KIC 8463852? Possibly, especially if the orbit is elliptical.

The star closest to our sun is the trinary star system, Alpha Centauri, at 4.3 light years distance. It can be predicted that the two bigger planets in that system, being only 11 AU apart and both similar to our sun in size, play havoc with anything trying to orbit them. The third star, Proxima Centauri, is a dwarf and is half a light year away so it doesn't affect the system much.

If our sun had a companion which was a significant fraction of the sun's size and on an elliptical orbit 93 billion miles away, it's fair to say that it would wield a dramatic gravitational effect on our system.

Of course, the 93 billion miles might be the closest approach, the middle distance or the farthest from KIC 8462852 as we see it now. So it will take much more observational data to determine if it's the reason for the strange transit data we're seeing.

The quandary is this: We've observed countless other binary star systems and have not seen anything similar to KIC 8462852.

Thanks. Glad you're participating in the discussion. Sunspots can certainly affect a star's flux.
LINK

quote:

---

Another possibility is that sunspots are to blame. Our Sun rotates with a period of twenty-seven days, but KIC 8462852 spins much faster, completing a rotation in just 0.88 days. A dark region on the star would disappear from view in less than a single day and some of the decreases in the starlight measured by Kepler last for several days. Sunspots don’t add up.

---

So, the very fast rotation of KIC 8462852 eliminates the possibility of sunspots as the cause of the extraordinary dimming. If the star was spinning at the sedate pace of our sun, it would definitely be considered as a cause.

By the way, some of the decreases in flux last for months, not "several days" as mentioned in the article. That's one of many fascinating puzzles to be solved regarding this unusual star.

It's definitely exciting, if only because it's something brand new to astrophysics. We're definitely going to learn something from this system.

Frightening? I guess so, especially if it turns out to be an artificial structure. I think we fear alien contact because they might be like us, hostile and warring. We're all we know after all.

Yeah, the thought that aliens would be hostile has always amused me. In comparison, we'd be the infantile ones during the interaction, flying out our measly fighter jets and little bombs, poking our chests out like we're big. Ultimately, they'd probably leave very quickly and leave us to wallow in our destructive, dysfunctional ways. Society as a whole panics when they don't understand something, that panic leads to frustration, which ultimately leads to anger and aggression. Mankind addressed that chain of events by creating religions, leaving most people to wipe their hands of it so to speak.

quote:

---

I think it was Lovecraft who said "The oldest and strongest emotion of mankind is fear, and the oldest and strongest kind of fear is fear of the unknown".

---

We will be a mature species only when we regard the unknown as an opportunity to learn. The examples are numerous where humans try to stop time.

The Amish and many other religious groups resist change. Cults inevitably declare that everything important has been determined and is a reservoir of knowledge that only the cult leader has access to for guiding the group.

quote:

---

I think it was Lovecraft who said "The oldest and strongest emotion of mankind is fear, and the oldest and strongest kind of fear is fear of the unknown".

---

So Lovecraft was writing about women? Men can go to the moon, but desire invisibility when women ask "does this dress make me look fat"?

quote:

---

Assuming intelligence is directly associated with technology, we should see evidence of its use as a first marker of intelligent life. Absolutely nothing has been seen.

---

I don't remember which science show I saw that addressed this point, but they said that concluding there is no intelligent life based on our not having observed evidence of it yet would be like going to the beach with a bucket, dipping the bucket in the water and, if there are no fish in it, concluding that there are no fish in the ocean.

quote:

---

One of the most outstanding discoveries of the mission so far, is the detection of large amounts of free molecular oxygen

---

The discovery of oxygen in the atmosphere of a planet orbiting Tabby's Star (I'm tired of typing that log number ) would be clinching evidence of a civilization in that system. Of course, no planet transits have been observed because of the gigantic structures that are apparently interfering.

When the James Webb Space Telescope is launched in October 2018, we will have the ability to see and analyze some of the exoplanets' atmospheres. Hopefully that will include any planets we discover around Tabby's Star in the meantime.

quote:

---

I don't remember which science show I saw that addressed this point, but they said that concluding there is no intelligent life based on our not having observed evidence of it yet would be like going to the beach with a bucket, dipping the bucket in the water and, if there are no fish in it, concluding that there are no fish in the ocean.

---

That's a good analogy. Our present technological abilities are analogous to going to the beach and looking out over the water. If we don't see anything protrude above the water's surface we conclude there's no life in the ocean.

Of course, we do frequently see life in the ocean with this technique, because we know how to recognize life in the ocean, and that's where this analogy breaks down regarding our simple observations of the Universe. We peer at galaxies, for example, looking for infrared markers of technology by advanced alien civilizations.

We've seen nothing with this strategy possibly because we don't know how to recognize alien technologies. This may also be true concerning Tabby's Star.

SETI will be looking only for radio signals. So will the Very Large Array in New Mexico and the Greenbank Observatory in West Virginia if SETI discovers anything interesting.

Radio telescopes are the limit to our abilities until the James Webb Space Telescope is launched. Maybe the Hubble Telescope can give a bit better image of the Tabby's Star neighborhood but it's limited to looking at very large structures at the distance to that system.

We may be waiting a few years for definitive evidence one way or another about the nature of the Tabby's Star system.