We are some of the astrophysicists and Planet Hunters behind the discovery of KIC 8462852 (a.k.a. Tabby’s star), the mysterious star that has become a favorite SETI target. As us anything!

Do you really believe that a swarm of comets could block 20% of the light of a star?

Sure, if they were very very very large comets, bigger than anything we've ever seen before.

sorry for my lack of knowledge, but a comet wouldn't reflect some of the light, or there are comets made of light absorbing materials?

When the material is between us and the star, it reflects (scatters, technically) light that would have come towards us out of our line of sight. To observers in the system, they see this light as a bright comet tail and nucleus, but for us it's just light lost, so a dimming.

I think in Tabby's model there is also a lot of absorption by dust going on, in addition to all that scattering by dust and gas. That's something that will have to get worked out in the detailed models to test the comet hypothesis.

Do you have an idea of when you will be granted time at the Green Bank observatory? (beggining of the year, middle, never...)

I hope we'll be granted time to observe in January. One reason for the delay is that this is the natural cycle of telescope time allocation (time is allocated semester-by-semester). That said, we could have asked for "director's discretionary time" on shorter notice.

The other reason is that we would like to use the new Breakthrough back-end, which should be ready by January 1st. As I understand things (I am not a radio astronomer) this is basically computer hardware that processes the radio signals and sifts through it for signals. The data have to be reduced to something like 1/100 of its native volume in real time to create a manageable data volume to save for later analysis, and the Breakthrough Listen Initiative has provided the Berkeley SETI Research Center the funds to build and install this specialized hardware at Green Bank.

I hope other people take note of this crap. One of the coolest discoveries in space of our generation, but you still gotta put your name on a list to use some equipment.

TAKE NOTE CHILDREN!!

Not sure if you're being facetious in calling the time allocation process "crap". I did write that we could ask for directors discretionary time and jump the queue. Most telescopes have this feature for exactly the reasons you seem to be implying.

If our own star had an event occur to disturb the Oort Cloud, do we know if there would there be enough matter to dim the visible light by 15 to 22%? What do we know about Oort Clouds around other stars in terms of ability to block visible light? Lastly, would a "recent" event lack IR emission vs. a comparatively "older" event?

If by "event" you mean something that created a large cloud of dust, then no. A recent event would have more IR emission—one hypothesis is that our infrared measurements are out of date, and so something like a giant planetary collision might have happened since they were made and caused the dips Kepler sees. I've heard rumors that astronomers have now ruled that out.

The quantitative details of the comet hypothesis still need to be worked out, but my understanding is that there is plenty of material in an Oort cloud, or even a single asteroid, to block that much light if you grind it up fine enough. The question is how do you grind it up and get it into a big, star-sized cloud?

Thinking about the kind of process it would take to essentially create such a cloud, are there any theories currently out there that best fit this concept? Would a swarm of comets flying inward toward the star would have a more triangular shape? Are we thinking the cloud has a certain shape or dynamic to it (circular)?

I don't know. I think this is part of the quantitative and astrophysical work that needs to happen to turn the comet hypothesis into a working theory.

What do you like to imagine it is? Do you have a specific personal hope for what it could be?

Of course I'd love for us to finally find evidence of alien life, so I hope that's what it is. But I also presume the chances of this are very low, and so I don't get my hopes up.

Of course aliens would be exciting, but it's important to be open to whatever it happens to be. If you start getting too invested in a hypothesis, it compromises your objectivity.

Dr. Wright, I took Astro 001 with you a few semesters ago and you made the class, pun intended, an out of this world experience. Thank you for being a great teacher.

Two questions: what, in your opinion, is the likelihood of these objects being extraterrestrial?

Secondly, how fun is it to teach that gen ed class and see the reactions of non-science majors?

Glad you liked the class!

I don't know the likelihood that it's from an alien civilization, but I presume it is very small.

I really enjoy teaching undergraduates astronomy. There's so much amazing material to cover, and it plays such an important part of our understanding of our place in the cosmos.

Thank you for answer all of these questions thoroughly, I appreciate your thoughtfulness. But no one has asked you the most pressing question. So, if I may,

Would you rather fight one horse sized duck, or 100 duck size horses?

Keep in mind. They want to kill you.

Definitely a horse-sized duck.

Birds’ bones are optimized for weight and flying, and many are hollow. The surface area to volume ratio of a horse is much lower for a duck, and so the weight the duck’s bones must support will grow with size much faster than the ability of the bones to support it.

A horse-sized duck would be pretty fragile. If it could even stand, I doubt it would survive even the small amount of fight-for-your-life violence I could muster.

On the other hand, 100 of anything would be very hard to fight, especially assuming that they are out for blood (I’m assuming that I was their choice for opponent because they deemed me easier to kill than some other silly alternative). Duck-sized anythings don’t sound very dangerous, but I suspect most people that think that way end up like Dennis Nedry.

It is my understanding that after a week of radio signal monitoring by SETI there is a lack of radio signals. Are civilization hunters taking into account that radio signal emission may just be relevant to start up civilizations like our own, and more advanced civilizations may have found a better way to communicate that we cannot yet detect?

Radio SETI astronomers are very aware that advanced civilizations may not use radio. Indeed, our civilization is already moving to fiber optics. There is now a field called optical SETI that focusses on laser communication.

There are several lines of reasoning for why radio may nonetheless be detectable. One is that it's an easy and cheap way to announce one's presence (a "beacon") that even a civilization as young as ours could detect.

Another is that it's an easy and cheap way to communicate across interplanetary distances, and to scan a system for objects with radar — in either case we might catch "leaked" emission not intended for us.

The bottom line is that there are only so many ways we can hope to detect any communication for advanced alien civilizations. We don't know what their psychology, motivations, or communications technology will be like, but we do know that today we have the technology to detect our own technology from another star. So it makes sense to look, just in case.

we do know that today we have the technology to detect our own technology from another star.

Can you elaborate on this? Just about everything I've read that has been written by a technically informed author points to leaked earth radio signals as being virtually undetectable from background noise after only a few light years. It would take 110 million Watts to get a voyager-strength signal to proxima Centauri, only 4 light years away (most broadcast stations don't reach 5 million Watts). KIC 8462852 is 1500 light years away...

Or are you talking about some other method of detection such as atmospheric spectroscopy?

I wasn't writing about leaked emission. I mean that our most powerful radio transmissions (like the Arecibo radar) are strong enough that our most powerful radio telescopes (like Arecibo) could detect them from alpha Centauri, if we knew where and when and how to look.

The AAVSO put out a call for observations of KIC 8462852 last month. Do these end up going to you or your team? What sort of observations would be most useful? What radio wavelengths are you looking at / planning to look at to investigate this star?

I'm very grateful for the efforts of AAVSO members to help us follow this star.

The data from the many observers are of variable quality, so I'll need to do some vetting and cleaning to combine them all and get a good alert going. So far, I haven't figured out how to download the data as they come in a way that I can easily use. I've put out some questions to the AAVSO to help with this, but if anyone reading this knows the answer I'd appreciate the help.

If it's dust, why isn't it giving off infrared heat? How big of a comet swarm would it have to be to cause dimming 20 times that of what a Jupiter sized planet would cause?

It takes much less material to block starlight than to create a noticeable infrared glow, especially for material as cold as we think the eclipsing stuff is. There's plenty of room between the amount of material we see eclipsing and the amount that would be noticeable in the infrared that it's disappointing but not surprising that we don't see a midinfrared excess (that is, infrared emission above what the star puts out on its own).

Given the likelihood of another large dimming event being captured in less < 10 years by multiple telescopes. Will you be able to tell what type of material (dust, solid objects) and/or shape of the material?

Yes, we can perform spectroscopy on the light as it passes through the intervening material, or even just see how much visible light is blocked compared to, say, UV or IR light. This will help us determine what the material is made of.

Do you feel the layman attention this has garnered is good (more resources focused on this) or bad (mischaracterization, and disappointment when we aren't taking to aliens tomorrow)?

Also, telescope time is always limited, but this object is of great interest. Will there be many more observations to nail down what is happening?

The media frenzy was both good and bad. Some of the reporting was truly terrible, and that's never a good thing because it hurts science literacy. By contrast, some of the better reporting has taught the public about a lot of concepts you normally don't see discussed in the media, which is good.

Another benefit of the attention to the star means that many more astronomers and observatories have now heard about it and will work with Dr. Boyajian to figure out what's going on!

Do the Aliens have two sexes, like we do?

Hi, Jason.

Dunno, but I do know that an advanced civilization, by definition, is not barbaric.

Hi 'Zed

How does the comet swarm theory explain the significant differences in the morphology of the two dips? The first event appears strongly peaked at a single dip, but the second has a bunch of secondary dips. Wouldn't you need to strongly fine-tune the first event to present secondary dips?

I think the idea is that each dip is a different comet. Bigger dips => bigger comets. More dips => more comets in that swarm.

The exo-comet scenario assumes an eccentric orbit around the F star; it's possible that after the first significant dip, tidal disruption has occurred and resulted in fragmentation and some degree of sublimation of one or more large progenitor objects. In theory this could account for the more complex morphology observed in the second pair of large dips. -Daryll

Yup. It's a scenario like that that has some astronomers hoping to time their observations for the next passage of the (putative) comet swarm.

Do you think that there is even a remote chance, we pay a visit to aliens someday? Or vice versa? The universe is too big of a place.

Travel between the stars is not something I expect I or my children will see in our lifetime. If we ever, in the distant future, establish outposts around other stars, then I expect that we will eventually go on to explore the entire Galaxy. If there is alien life out there, our distant descendants might visit it.

What kind of credentials do you need to do what you do? For years I can't look up at the sky without being amazed at the stars. I've always wanted to work with space but I'm far from a Stephen Hawking. Where do I get my start!?

You need lots of training in skills that you can apply to these problems.

I got my start with a bachelor's degree in physics and astronomy at Boston University, and undergraduate research projects there and at Harvard.

You don't have to be a Stephen Hawking to contribute. Most of us aren't! There is room for lots of skill sets and spectra of abilities and talents.

I'm an I.T. professional so analytical thinking is what I thrive on. I can't believe some of the things you guys think of when it comes to the stars. Thanks for the reply! Have you ever worked with space programs on trying to develop new propulsion systems to help man travel faster? (EG "Warp Drive") or is it strictly planets, movements, etc. Can you also write me a recommendation to get into BU? :)

As an IT professional you have skills that would be very useful to astronomers. You could contribute as an IT professional at a NASA center, a university research center, or an observatory. This doesn't have to be a purely support role, either. Many of our technical staff do research, as well.

If what you want to do is switch fields into research astronomy, you'll probably need to pursue a graduate degree. If you want to study stars, that usually means you'll need a strong physics background, so you might need another bachelor's degree.

But I recommend informational interviews at the sort of places you might want to work. They might be able to point you in the right career direction, and introduce you to people that started where you are and ended up where you want to be.

Dr. Wright, thanks to you for being so available to answer questions. Similarly: I'm a geologist in mid-career but have followed astronomy since I was a little kid. It remains with me today. Was so honored to have the likes Carl Sagan write back to me as a kid when I had questions. Do you think it's ever "too late" to return to school, re-structure my degree, my career, and become an astronomer?

Geologists have plenty of expertise we could use now. We're starting to discover rocky exoplanets and we need geophysicists and geologists to help us understand what we're seeing. I'm not sure you need to restructure your degree, you may just need to talk to some astrobioligists / planetary scientists / exoplanetary astrophysicists to find a problem you already have the tools to work on.

So do you think we have approached the limit for the amount of information we will be able to tease out of the EM radiation we receive from a point source like this or are they working on promising new techniques?

We have barely begun to tease out the radio signals from this star. There are still lots of things we can do with UV/O/IR light if we could catch the thing in eclipse again.

What does the observed behavior of the star tell us about the size of the obstruction? Given what we know about stellar luminosity, flux, lensing, etc., what amount of obstruction would explain the data? And how does it vary between something like a dust cloud versus one or more solid objects, such as a smashed planet or a Dyson cloud? If these are manufactured megastructures, how preposterously huge would they need to be?

The duration of the events tells us it must be some combination of slow moving and large.

The depth of the events (up to 22%) tells us that it (at least, the biggest occulter) must be at least half the radius of the star. If the occulter is not completely opaque, then it must be even bigger than that.

Keep in mind there are many events, each of which implies a different size and shape of occulter. Also keep in mind that grazing eclipses would make the occulter appear to be smaller than it really is, because only part of it is blocking the star.

The depth of the events (up to 22%) tells us that it (at least, the biggest occulter) must be at least half the radius of the star. If the occulter is not completely opaque, then it must be even bigger than that.

Woah... wait... this just sunk in.

So it's apparent size relative to the star needs to be approximately 1/2 the radius of the star, but that means the farther from the surface of the star it is, the larger the object has to be. At 1/2 radius it would have to be orbiting right at the surface of the star, so we're talking about something really, really huge if it's out any real distance from the star.

Am I understanding this correctly? If so, my mind just boggled at the scale...

No, the star and the occulter are at about the same distance, so our perspective is pretty much orthographic. Put another way: it's 1400 light years away; putting it 1 astronomical unit closer doesn't make it any appreciably bigger.

What was the main event or "trigger" that made you want to search for ET life?

I saw an opportunity to do some work in the infrared that no one was taking: using the WISE catalog to do the first deep search for Dyson spheres. The John Templeton Foundation funded a competition for projects at the frontiers of astronomy and cosmology, and our idea won: http://www.newfrontiersinastronomy.org/

So, opportunity and funding.

My inspirations were the SETI researchers in Berkeley when I was a graduate student there: Jill Tarter, Dan Werthimer, and Geoff Marcy

Could the JWT be useful to shed more light on this anomaly? And any other future space telescopes, TESS, PLATO? Thanks.

Yes, TESS might detect another dimming event. JWST (and even plenty of other telescopes we use today) will be able to tell us what the material is made of if we can catch it "in the act" again. We've got lots of telescopes monitoring the star, and we're setting up alerts so that if another eclipse occurs, we can study the spectrum of the dimming and finally get some handle of the nature of the intervening material.

Because TESS will be an all-sky survey, and won't be looking at one area for as long as Kepler did, will there be more public outreach efforts in 2017 for ordinary citizens to help analyze and interpret data to find that next enigma, such as KIC 8462852?

No reason to wait for 2017. If this star goes into eclipse again tomorrow, we want to know right away so we can catch it with lots of professional equipment. The events lasts hours to days, so we might not have much time.

The AAVSO has information on how ordinary citizens can monitor the star with amateur equipment at sufficient precision to detect the largest eclipses seen by Kepler.

In the meantime, I'm trying to figure out how to use the AAVSO's data to set up a high-confidence alert. If anyone knows how to do that, that would be very useful.

In the WTF paper, section 4.4.3 indicates that the 1,500-day dip would roughly correspond to an object(s) with an orbital distance of 1.6 AU - for an F3 IV/V star, isn't this orbital distance near the habitable zone for that type of star?

I think it's about right, yes, certainly within the uncertainties of the estimate of the orbital distance.

Is it possible that the light of the star may be blocked by an object in our own solar system? Like the hypothetical planet x?

No, this scenario is ruled out by many aspects of the light curve: in particular how long it takes the star to get dim, then bright; the fact that the dimmings go on for four years, and the fact that no other stars in the field experience similar dimmings.

The material almost certainly has to be in orbit around the star, or at least at a distance consistent with it being in orbit.

Is there a planet the size or Jupiter or bigger around the star. If so should most of the objects be captured by it.?

We don't know of any planets around the star, but it's not very amenable to planet-detection, so we don't know if it has planets around it. Planetary dynamics are complicated, so it's hard to generalize about what the effects of such a planet would be.

Wouldn't a large megastructure likely be in orbit around the star, causing a regular pattern?

Wouldn't it have made more sense to have SETI observe this before allowing the media to sensationalize it?

We think whatever the occulters are, they are probably in orbit. If the orbital period is longer than 4 years, we would not see a regular pattern.

We did not advertise the SETI angle to the press. The media does not ask permission to sensationalize.

What were some of the most detrimental media mistakes in this case? Were there any in particular that really annoyed you?

https://t.co/gbf52Fg7cy

As a professor, no doubt you have some advisees and grad students under your wing who do some cool work as well. While it may be a bit off topic, can you tell us all about some of the other work you and your students do?

Katherina Feng, Eunkyu Han, and Jacob Brown are (former and current) undergraduates that have done work maintaining the Exoplanet Orbit Database. http://exoplanets.org http://science.psu.edu/sciencejournal/archives/june-2013/department-news/astronomy-astrophysics

My student Kimberly Cartier contributed to our analysis of what the light curves of a transiting megastructure might look like. http://sites.psu.edu/astrolady/

Jason Curtis works on determining stars' fundamental parameters and ages. http://sites.psu.edu/jcurtis/

Sharon Wang is perfecting the precision with which we can detect stellar motions indicative of planets orbiting them: https://sites.google.com/site/sharonxuesong/

Arpita Roy has done work with me on the Lunar Farside Highlands problem, the Habitable Zone Planet Finder spectrograph we are building for the Hobby-Eberly Telescope. http://www.personal.psu.edu/aur17/

The companion star that is 130 Billion miles from #KIC8462852, what is its name? What do we know about it? Are the two stars a binary pair?

Have certain ideas evolved since publishing the WTF paper? Or are all these hypothesis stagnant until more observations are made?

Has anyone contributed a new feasible idea from any community of fellow scientists, the media, or the social media community since this became public? Seems like you have already covered all ideas that I see people ask you. Anything new that has made you stop and think?

I think we would call it KIC 8462852 B.

I have heard a few neat ideas since publishing, including at least one that is really novel, but nothing obviously more plausible than the ones already discussed.

"I think we WOULD call it..." oh, so the M star that is 885 AU from Tabby's is not necessarily proven to exist yet? And therefor you can't say if it is a binary system or just transisting by yet?

There is certainly an M star that appears near Tabby's star on the sky. We don't yet know for sure if these two stars are bound or at the same distance.

The standard nomenclature in binary systems is to call the two components A and B in order of brightness.

Just saw this AMA. I've been fascinated by space and astronomy since I was a wee tot. I'm in the IT field and never really pursued astronomy seriously as I was never encouraged to do so by my family growing up. My question is this:

I have a 3 year old daughter who absolutely loves space, stars, and astronomy. She badly wants a telescope and will probably get one some time in 2016 when she's a little more coordinated. What else can I do to encourage her and keep her enthusiastic about space and the sciences? Certain books aimed at pre-schoolers? Activities in PA (ie aware of any kid-centric activities at Pitt/PSU/etc)?

Thanks for your time!

AstroFest during Arts Fest at Penn State astronomy.

Astro Night at Penn State astronomy in the fall.

Buhl Planetarium in Pittsburgh.

A good pair of binoculars with a very good mount/tripod.

The Max books: http://www.bigkidscience.com/books/

I'm sure there are lots of other resources, maybe others can supply more in the comments.

Maybe this has been answered before, I haven't looked too closely, but what type of data would you expect to see from the radio observations? And if the data leads to a larger possibility of megastructures and rules out some other explanations, what implications would this have in the field of exoplanets and astronomy in general?

The purpose of radio SETI is to find signals that could not possibly be natural, since natural radio sources have a minimum signal bandwidth. It's hard to predict what the content of such a signal might contain. If it's a "beacon" it will presumably be simple and easy to detect and interpret, but that's just a guess.

Are instances of multiple, semi-periodic occultations such as this so rare, much less unprecedented? How is it that another astronomer who has worked at SETI can declare that they are not? I find the contradictory statements very confusing.

You'll have to point me to the contradictory statement you mean.

Light curves like this are certainly unprecedented for mature stars. Very young stars can have disks and protoplanets that can create very strange light curves (although we've never seen one quite like this, it's at least the same category).

The statement was not an official pronouncement, but rather a Facebook comment by Rowen Poole:

I am doubting the alien megastructures theory. It's an F3 V star - which means it's larger, hotter and younger than our sun (though not extremely so). ie - life would have evolved sooner on a planet circling it. Possible? Yes. Probable? Hmm.

The light curve shows interesting variations but not totally unlike stars I have studied over the years. There would appear to be a tight group of large objects orbiting the star. A tight group of comets near the star? Yes. Possible. it could also be explained by the breakup of large moon/planetary body in the relatively recent past (over time debris spreads out). The Earth was hit by an object about the size of Mars 4+ billion years ago. The end result was our moon. Although such things generally happen early on in a solar system, it's not impossible for it to happen billions of years later. The Earth could still be hit by a large asteroid at some point in the future (ask the dinosaurs...).

I don't know whether life around an F3 star is more or less likely than on Earth. Claiming it's less likely strikes me as an unwarranted Earth-centric assumption. Remember, alien life is likely life-as-we-don't-know it.

The planetary collision hypothesis is hard to reconcile with the data because of the lack of infrared excess one would expect from such a recent collision. The resulting debris cloud would also be extremely short lived, so very unlikely to have been spotted by Kepler.

The light curves Poole is discussing seem to be associated with young stars which, as I said, are somewhat reminiscent of Tabby's Star.

The planetary collision hypothesis isn't impossible, and given the failure of most other guesses to date, it shouldn't be ruled out.

I have my computer running SETI@home pumping away calculations. Will my computer be contributing in any way to help with this specific star?

Also, Is there anything I could do to help? I absolutely love astronomy and would be ecstatic to contribute.

I think SETI@home will help with the data analysis from Green Bank, since it's run by one of the Breakthrough Listen Principal Investigators, but I don't know for sure.

We could use help monitoring of Tabby's star, either from people with the proper amateur telescope equipment, or from people that can gather the data going into the AAVSO and organize it in a useful way to generate an alert when it goes into eclipse next.

If this event is being caused by some alien mega structure (death star/halo size object), what would we expect to see with the scientific instruments we have looking at it today?

We would probably expect that the eclipses would be equally strong at all wavelengths, with no evidence for dust (which blocks more UV light than IR light) or gas (which absorbs a few, select wavelengths much more than others).

But would that be enough for scientists to say "it's almost certainly an alien structure" ? If not, what standard of evidence would that take?

That's very hard. Radio or laser signals from the civilization would clinch it, I think. It's a very distant star, so actually imaging the structures in reflected light might require a tens of $billions project and decades of work.

But astronomers are clever. If we thought the likelihood were high that it was artificial, we might think of definitive ways to test for that that I haven't thought of.

I was listening to Art Bell talk about this star the other night. He said he has a connection with someone in NASA that says there is a perfect triangle shaped structure orbiting around that star. Can you confirm this?

I can confirm that this is not so.

If there were a perfect triangle-shaped structure orbiting the star that looked something like this, then the light curve of the structure as it passes in front of the star would look something like this. However, I don't think anything in KIC 8462's light curve suggests that.

Taken from the paper by Luc Arnold, 2005.

You are incorrect; the curve would not look like the one you suggested; if you read the paper/diagram more carefully you will notice that it represents the magnitude difference between a spherical transit and a triangle transit, NOT the actual shape of a triangular object's transit light curve.

My mistake, I haven't looked at the paper in a while.

http://sites.psu.edu/astrowright/wp-content/uploads/sites/9476/2015/10/8462852_q8.png I believe that this light curve from KIC 8462852 is approximately the light curve expected from an isosceles triangle, entering the field of view narrow end first. It is difficult to find published research on the specific light curves generated by various geometric shapes. The paper you reference is frustrating in that while it mentions various artificial transit shapes, it only shows the magnitude differences relative a transiting spherical body; however, it was probably the best treatment of the topic I have found so far (with the exception of the recent "The G Search for Extraterrestrial Civilizations" (also by Wright, et al)

I agree that, to first order, the event you linked to seems like the sort of thing a long triangle could produce. We noted this in our paper (for a different object with a similarly shaped transit signature).

Here is some code that you can use to try to see if it works in detail: https://github.com/hposborn/Draw-A-Transit

Here are the data themselves: http://exoplanetarchive.ipac.caltech.edu/cgi-bin/bgTools/nph-bgExec?bgApp=%2FETSS%2Fnph-etss&etss_dataset=Kepler&etssdetail=8462852&etssfind=View (click on "download all light curves").

If you guys are still answering questions, I'm going to ask something a bit different than others (and possibly more personal).

This is the kind of discovery that really puts you and your work in the public eye, not just in astronomy social circles, but pretty much the entire population of the world.

Tabby, in particular, - since it was your team's discovery, how has this changed your day-to-day operations? Do you find yourself dealing with a lot more media than you would like or is it more fun than you would've expected? What has been the most surprising part of this experience for you?

tl;dr: OMG, you're famous! Cool, huh?

I've hardly gotten anything done since the story broke.

How long will it take before we're in a position to determine whether or not there is an intelligent civilisation near that star? Are the people who control the money needed to enact the research and obtain the technology excited at the possibility in any way?

The most definitive detection would be a radio or laser signal, though of course we don't know if an alien civilization would emit anything detectable.

We'll know more if/when we detect the star go back into eclipse.

What circumstances do you think will lead to humanity eventually attempting to colonize space?

How do you think we will go about the logistics?

Personally I think we won't make a successful attempt until our backs are against the wall in some form or another.

I'm torn; I can see both a private/corporate path to a permanent human presence in space, and also International-Space-Station-style governmental approach. Perhaps we'll do both.

I don't think having our backs against the wall will drive much. Settlement of space is a long-term project requiring lots of planning, and at best only a trivial fraction of the population of Earth would ever leave emigrate from the surface.

If we continue to receive a lack of intelligent radio transmission, what other important data are we currently observing that says, "this structure doesn't seem natural?" Also, have we really been observing long enough with the radio frequencies to say we can close the book on any intelligence at KIC 8462852? I love how the media immediately shoots down the prospect of life at the first report of no findings....

It's a bit disappointing that the ATA didn't see anything in its recent 2-week-long stare, but not entirely unexpected. The ATA is a pretty small telescope array, so it would take an outrageously powerful transmitter — pointed right at Earth and broadcasting in an obvious way — for them to have detected anything. Andrew Siemion and I hope to soon use the Green Bank radio telescope — which is thousands of times more powerful — to check for less-outrageously powerful transmissions across a broader range of frequencies and signal types using a new instrument funded by the Breakthrough Initiatives. We don't know what sorts of transmissions an alien civilization might broadcast — if any! — but we do know that it's important to look.

We can also look at the transmission properties of the material in the next eclipse. If it is much more opaque in the ultraviolet than at visible wavelengths, we can rule out large opaque structures. If it is the same depth in all wavelengths, including at frequencies favored by gases, most of the currently favored natural explanations will go out the window.

Whether this proves to be natural or artificial, do you think that this could potentially be a way for us to signal our presence to other extra-solar civilizations? Could we manipulate a dust cloud so as to create a dimming effect for those looking in our direction?

There's a paper about this, actually. It's what got me thinking about this in the first place: http://arxiv.org/abs/astro-ph/0503580

Do you believe that life can exist on Kepler 186f?

I think life could potentially exist just about anywhere with heat and a solid surface and/or water ocean. I suspect life-as-we-don't-know it could even exist without water.
I don't know the odds of it existing on any particular planet. That's why we look.

Of course this will be wild speculation, but if/when we do find signs of life somewhere in the universe (KIC 8462852 or elsewhere) what do you think it will look like? A serious or humorous response are both acceptable.

I think the evidence will slowly build, like the evidence for water on Mars, as a series of small at-first-ambiguous but ever-more-convincing discoveries. We'll find out-of-equilibrium chemistry in an exoplanetary atmosphere, learn more and more about it, and eventually study the surface of the planet itself and see seasonal changes to its surface. It may be very hard to ever study anything analogous to megafauna, but we will be able to study the ecosystem as a whole, including the primary energy capture mechanism (on Earth that's photosynthesis via chlorophyll).

I think the asker wants to know what the aliens would look like, not the process.

I have no idea what it will look like, but I imagine it will be microbial.

Do aliens exist and are they being hidden by the government?

No.

But then, I'm not in the government.

Have there been any simulations/calculations showing that such a group of massive objects could be in a somewhat stable orbit, at least stable enough not to require massive luck to observe them just at the right time to see them in this configuration?

I don't think so, but hopefully the Planet Hunters can answer.

What would be the steps following the reception of an alien radio signal. If a transmission was received from this proposed civilization would you expect the signal to be from the early stages of this advanced civilization?

The purpose of radio SETI is to find signals that could not possibly be natural, since natural radio sources have a minimum signal bandwidth. It's hard to predict what the content of such a signal might contain. If it's a "beacon" it will presumably be simple and easy to detect and interpret, but that's just a guess.

Alien civilizations will almost certainly be much more advanced than we are.

Have you considered it to be a large Oort cloud made of lead that obits at an extreme distance from its star? The lead would explain the lack of IR radiation.

The distance from the star does not have to be out in the Oort cloud to make the IR undetectable; a few AU would do it if there is not too much material.