Astronomers may have found giant alien 'megastructures' orbiting a star in the Milky Way

[fredinno]

If it is aliens, I think we should make every peaceful effort to get their attention. It's best to have help from a civilization more advanced than us. I wonder if they have sent probes to this system yet, I doubt they have but they probably can see our oceans, the composition of our atmosphere, etc., and suspect something's existence. Although they might be scared of us if we try to peacefully contact them, because their media might portray aliens like ours does.

Also, there is a new theory about the light fluctuations. It's that the star is elliptical, and so the poles are hotter and brighter. Unfortunately, since the star can only be elliptical through the axis of rotation, it can't really change its apparent ellipticity from any given point without being constantly tugged into an oval shape by another massive object. There is no discovered massive object that can account for this.

If they can make dyson spheres, they won't be scared of us. Also, I find it hard to believe at least one probe wouldn't be sent in our direction, if they existed. To us, it'd look like a comet travelling at sun escape velocity.

[Rakaydos]

If they can make dyson spheres, they won't be scared of us. Also, I find it hard to believe at least one probe wouldn't be sent in our direction, if they existed. To us, it'd look like a comet travelling at sun escape velocity.

There's a lot of stars in a thousand lightyear bubble. (500 light-local-year, for them) Perhaps they simply havnt gotten around to it yet.

[Stargate525]

There's a lot of stars in a thousand lightyear bubble. (500 light-local-year, for them) Perhaps they simply havnt gotten around to it yet.

Or they have, but we weren't looking at the time. Honestly, would a probe zooming through on its way to somewhere else be noticed in 538AD?

[K^2]

Also, I find it hard to believe at least one probe wouldn't be sent in our direction, if they existed. To us, it'd look like a comet travelling at sun escape velocity.

Why? There would be thousands of more interesting stars closer to them. Even if they were looking for life, and managed to image Earth with a giant interferometer, at best, they'd know we have oxygen. And maybe they've sent a probe to take a look. Odds are, it would have passed through our system many thousands of years ago. And even if they kept watching, given speed-of-light delay, we're still going through late Roman Empire days for them. So no signs of civilization that they'd be able to detect. Maybe, if they are still watching, 1,400 years from now, they'll detect radio signals from Earth and send another probe. Maybe it will get here in 10,000 years or so.

[EliasDanger]

We should send them a message that asks if they have a time machine to come visit us shortly after we send the message so we figure out right away if advanced civilizations can time travel.

[Aethon]

would a probe zooming through on its way to somewhere else be noticed in 538AD?

Not even today. A small probe on a hyperbolic trajectory may be detected, but would be assumed to be a comet, like fredino said. Even a large probe would be considered a comet.

Now if it was big enough, and tried to make solar orbit...

Centauri Dreams has had good coverage of this lately, several articles in a row.

http://www.centauri-dreams.org/

Edited October 27, 2015 by Aethon

[Mazon Del]

Finally just got some info I was looking for concerning this, and its a 'little' disappointing in a way. The dips in light appear every roughly every 750 days. The first was March 5th, 2011. The second on February 28th, 2013. Unfortunately due to the loss of two of Kepler's reaction wheels, the dip 'scheduled' for April of this year was not recorded. The next one is May of 2017. So all the various people setting up telescopes to do spectroscopy and such in the hopes of identifying what the objects are made of will have quite a wait. The hype will probably subside rather far by then unfortunately. We can only hope there will still be a good amount of tools pointed its way next time around.

[YNM]

Spectroscopy observations are done best around a quater of period before/after the expected eclipse. So... A quarter of 750 days is around 188 days after april, in other words around October...

Somebody should contact STsCI immediately ! Or NSF. Or anyone else...

[Mazon Del]

Interesting, I did not know that. Any reason why that is?

It might explain why random people are setting up telescopes to look at it. I had been confused when I realized the sort of wait they were going to have, guess i know why. Note: I'm aware that the SETI ones make sense given they are looking for radio rather than the objects themselves.

[problemecium]

Can I make a humble request?

This thread's been around a while and I keep seeing it on the front page, and the title says "star near the Milky Way." But the star is IN the Milky Way - it's NEAR Earth (on a cosmic scale). Would someone mind indulging my obsessive compulsion and fixing the title?

That'd be great, Thx ^^;

[andrew123]

Can I make a humble request?

This thread's been around a while and I keep seeing it on the front page, and the title says "star near the Milky Way." But the star is IN the Milky Way - it's NEAR Earth (on a cosmic scale). Would someone mind indulging my obsessive compulsion and fixing the title?

That'd be great, Thx ^^;

I fixed it for you. ^ ^

[YNM]

Interesting, I did not know that. Any reason why that is?

It might explain why random people are setting up telescopes to look at it. I had been confused when I realized the sort of wait they were going to have, guess i know why. Note: I'm aware that the SETI ones make sense given they are looking for radio rather than the objects themselves.

Simple axis projection, coupled to orbital mechanics.

1. Object moves in pretty much circular path wrt parent star. This means there's some time when it pass in front (eclipsing the star), then pass behind (elipsed by the star). In transition, the object has to move forward or backward. If you define a period as the time elapsed between two star eclpses, then the time between the object eclipsing and being eclipsed is half the period - transition goes between that so half of half the period (a quarter).

2. During eclipsing / eclipsed, the star and the object moves only sideways. In transition, there'll be a point where they just move forward / backward without any sideways component.

3. Sideways (tangential) velocity can be inferred as a movement on the sheet of sky.

4. Radial (towards / away movement) velocity can be inferred as changes (specifically, shift) in spectrum.

The caveat is that we're measuring the star's radial velocity in any case - so when the object moves backward, the star comes forward. When the object moves forward, the star goes backward. And the ratio of mass between two object is inversely related with their velocity - there's a good chance the radial velocity we're going to measure is even slower than walking speed ! Combined with the fact that we want their distribution too, the best option (but highly resource-consuming) would be constant monitoring, at least every few (2-5) days.

Edited November 1, 2015 by YNM

[problemecium]

I fixed it for you. ^ ^

Thanks! xD

[Mazon Del]

Thanks YNM!

[Spaceception]

Anything that can block 20% of a sun-like stars light is not a planet, or comets, it's either a "Alien Megastructure" and we're seeing Aliens in the middle of building a Dyson sphere or swarm, or it's something we've never seen before, but it's sure not planet debris or a comet swarm.

[Wjolcz]

What about a gas giant planet that mass is too low to become a star and doesn't produce any light, but has a giant ring system and is oriented like Uranus (about 90 degrees)? Would that be possible at 8 AU from the star? Wouldn't the rings get unstable? Could they be so big to block 22% of the star's light?

Edited November 3, 2015 by Veeltch

[problemecium]

To address the last two:

- It COULD be a cloud of comets. It'd of course have to be an enormous cloud of comets, which is unlikely, but as everyone's been saying, so are aliens (given historical trends).

- Unlikely. Ring systems tend to be round, so the change in luminosity would be symmetrical, even if a bit jagged. Plus, planets always have a limited SOI, dependent on their mass and orbit distance. To have a large SOI, it'd either have to be huge (in which case it would make the star wobble, allowing us to identify it by the redshift), or very far from the star (which would cause it to move slowly and have a period much longer than 750 days). And the necessary size of a ring system that blocks 20% of a star's light is... practically a solar system in itself.

[YNM]

Anything that can block 20% of a sun-like stars light is not a planet, or comets, it's either a "Alien Megastructure" and we're seeing Aliens in the middle of building a Dyson sphere or swarm, or it's something we've never seen before, but it's sure not planet debris or a comet swarm.

What if it turns out to be... An exceptionally close and quiet blackhole ?

Don't theorize, just observe. We haven't observed any other wavelength, we haven't checked spectrum, we haven't started cataloguing them for some good period.

[Rakaydos]

What if it turns out to be... An exceptionally close and quiet blackhole ?

Don't theorize, just observe. We haven't observed any other wavelength, we haven't checked spectrum, we haven't started cataloguing them for some good period.

The way the signal brakes up, the obstruction is asymmetric, which rules out any singular source bound by gravity. But the shere size of the obstruction is enough to rule out most other explanatins.

[YNM]

The way the signal brakes up, the obstruction is asymmetric, which rules out any singular source bound by gravity. But the shere size of the obstruction is enough to rule out most other explanatins.

Still, waiting for more data is best.

[DBowman]

http://www.slate.com/content/dam/slate/blogs/bad_astronomy/2015/10/13/star_alien_dips.png.CROP.original-original.png

Kepler data show huge dips in brightness, up to 22 percent in the star. The bottom axis is days after an arbitrary date, and the bottom two panels are close-ups of the top one, centered near 800 days (left) and 1,500 days (right). The average amount of starlight over time is set equal to 1 for ease of display.

More info and I found the paper without the paywall.

http://www.slate.com/blogs/bad_astronomy/2015/10/14/weird_star_strange_dips_in_brightness_are_a_bit_baffling.html

Planet Hunters X.KIC 8462852 – Where’s the flux?

http://arxiv.org/pdf/1509.03622v1.pdf

the graphs didn't show but you can follow the post link to see em.

The graph looks consistent with an object between us and the star getting closer to us:

• apparent size larger => greater occlusion
  
• finer details resolvable => more complex occlusion signal
  

does that make any sense?

Imagine it kind of drifting 'randomly' in and out of the line of sight between us and the star. Though looking again at the graph the time between the two occlusion events is about 2*363.5 (by eye) - almost exactly two earth years between them - kind of a weird coincidence?

I've not tried to figure out how the two time & max occlusion % data points constrain possible size, distance, and 'closing speed' of 'the object'.

Edited November 4, 2015 by DBowman

[magnemoe]

the graphs didn't show but you can follow the post link to see em.

The graph looks consistent with an object between us and the star getting closer to us:

• apparent size larger => greater occlusion
  
• finer details resolvable => more complex occlusion signal
  

does that make any sense?

Imagine it kind of drifting 'randomly' in and out of the line of sight between us and the star. Though looking again at the graph the time between the two occlusion events is about 2*363.5 (by eye) - almost exactly two earth years between them - kind of a weird coincidence?

I've not tried to figure out how the two time & max occlusion % data points constrain possible size, distance, and 'closing speed' of 'the object'.

Could it just be inclination?

An large change in 720 days looks to me like an aftermatch of an catastopic even, the comet flock or major impact.

that someone increasing an dryson swarm so fast is not plausible if they could they would hardly need it

[CptRichardson]

Could it just be inclination?

An large change in 720 days looks to me like an aftermatch of an catastopic even, the comet flock or major impact.

that someone increasing an dryson swarm so fast is not plausible if they could they would hardly need it

Or the object rotates, so we got another axis that had a different shape to it compared to the original form.

[DBowman]

The two earth year periodicity is nagging at me...

1. It's just coincidence: okay sure, but weak. What are the odds that the only thing we've seen like this happens to have a 'resonance' with Earths orbit around the sun?
   
2. It's earth's motion around the sun bringing the object into occultation: what does this say about where it is and how big it is? I can only think of 'it's not orbiting the star, it's between us and the star' - any other possibilities?
   
3. ??? what are the other options?
   

[Findthepin1]

An object in a 720 day orbit around KIC 8462852 would be something with a semimajor axis near the inner edge of the habitable zone. About the analogue distance to where Earth is from the Sun. Comets aren't stable that close to a star. If the anomaly is indeed in a 720 day orbit, it wouldn't have any icy materials on it because a 720 day orbit's apoapsis is theoretically at most 4.1 AU from this star in particular. Sol's frost line is at 5 AU, and this star is significantly bigger than Sol. Its frost line would be much further away, maybe 10 or 12 AU, I don't know. Comets then are ruled out. If I'm wrong, because most people still talk about it being comets, please let me know.

Edited November 6, 2015 by Findthepin1