Anyone else thinking of the beginning of the utterly excellent "Pandora's Star" by Peter F. Hamilton?
Yes, except I hated that series :)
Tabby's star is dimming at an incredible rate
161–170 of 179 posts
Re: Tabby's star is dimming at an incredible rate
#162Earlier quoted context omitted.
Spectral type isn't 1-1 correlate with the star estimated life. Depends on the star mass. Our Sun was one time a F type star.
Do we have a "longevity" estimate for Tabby's star? By estimating how much starlifting would explain the observed luminosity drop, and then backing out the expected increase in the star's life against its flux decrease one could estimate how efficient the "aliens'" energy-harvesting technology is (coupled to a financial discount rate).
Plug its estimated mass (1.43 solar masses [1]) into the expression for main sequence lifetime [2] and you get ~4.1 billion years. But we don't know how old it is (the prevailing assumption seems to be it's old enough to have settled into staid middle-age behavior, making its variability harder to explain [3]).
[1] https://en.wikipedia.org/wiki/KIC_8462852
[2] http://astronomy.swin.edu.au/cosmos/M/Main+Sequence+Lifetime
Re: Tabby's star is dimming at an incredible rate
#163Could it have been hit by a large planet that lost its orbit somehow (perhaps from another system)? (And out of interest, is this an event that has been recorded before?)
I think this scale-correct image pretty much answers that: https://www.wwu.edu/skywise/solar/solar3.jpg
Tabby's star is a bit larger than the sun (1.4 solar masses) but you get the idea. You would need something much larger than Jupiter to visibly impact it.
Re: Tabby's star is dimming at an incredible rate
#164Earlier quoted context omitted.
IMHO the aliens will not be specifically seeking life that is intelligent. Singularities and interstellar traveling alien civilizations share a problem. If one is in essence immortal the only purpose that can endure forever is the pursuit of new knowledge. Even if alien entities are able to learn all there is to know about all the other sciences, biology will be inexhaustible as the novel patterns that can be produce…
> If one is in essence immortal the only purpose that can endure forever is the pursuit of new knowledge. That's making a lot of assumptions about alien psychology, believing they're going to have the same goals as us. Why not 1. Propagation of your species, forever 2. Expansion of your territory until the entire Universe is yours 3. Endless pursuit of pleasure 4. Propagating religious beliefs, or something we'd reco…
My unprovable assumption is that only beings who value knowledge and cooperation highly enough will get to the point of crossing the difficult technological threshold of achieving singularity or space travel. I think the more likely Achilles heel for my scenario is sexual selection - the trap that perpetuates selfish behavior in both sexes even when there is no resource scarcity. Even in this, humans at least are sometimes able to escape the trap by being meta enough to see kindness as strength and beauty. I think the fastest, and most likely first, route to our singularity will start with reverse engineering one human mind, and I will hold onto hope that that mind will hear the call of light, and the truth and beauty feedback loop will be unstoppable. It helps that I also believe that as information increases, morality converges on a process for maximizing the long term preservation of information (where on this planet, human minds are the most information dense and therefore the most valuable things we can preserve). /end sci fi sermon
Re: Tabby's star is dimming at an incredible rate
#165When Elon Musk and Jeff Bezos start building their mega structures around Mars, some far away alien species will report a similar sighting about us.
Re: Tabby's star is dimming at an incredible rate
#166> dimming at such an incredible rate that it can't solely be explained by any of the leading hypotheses
So it must be aliens. That can explain anything.
Re: Tabby's star is dimming at an incredible rate
#167Could an astronomer weigh in as to why the dimming effect isn't due to a 'rogue' blackhole entering orbit with the star and both blocking light and draining material from the star? I haven't seen that hypothesis dismissed yet.
Wouldn't that create a very regular pattern?
Re: Tabby's star is dimming at an incredible rate
#168The dimming is probably a dark matter nebula passing between it and us.
https://en.wikipedia.org/wiki/Dark_matter > The name refers to the fact that it does not emit or interact with electromagnetic radiation, such as light, and is thus invisible to the entire electromagnetic spectrum.
Couldn't it bend the light enough that it looks to be dimming to us?
Re: Tabby's star is dimming at an incredible rate
#169Earlier quoted context omitted.
Do spaceships travel in a straight line? I thought their trajectories are heavily curved in really weird ways due to the garvities of stars and planets around them. Please enlighten me!
It depends on the frame of reference, which can be somewhat arbitrary. A ship can sail a straight line from Falmouth to Boston, but that motion can be described as an arc because of the curvature of the Earth. Add in the motion of Earth's orbit, and the shape of that motion changes again. Add in the Solar System's motion relative to the Galactic Centre, and it's yet another shape. It's all a matter of perspective :-)
The straight line from Falmouth to Boston is only straight on a 2d map, because of particular transformation from 3d surface to 2d plane. Nothing to do with reference frame.
You indeed can change a curve into a straight line by manipulating the frame of reference, but it would need to be very contrived - basically you follow the object movement and add constant translation and some linear movement on top of that (one example - camera is in on a kite tied to the ship, and the rope is progressively loosened).
Re: Tabby's star is dimming at an incredible rate
#170Earlier quoted context omitted.
Reddit user sigbjoernwilderness's idea is pretty wild... can it be easily ruled out? > Is this the last remaining explanation after Montet/Simon? > The dimming comes from the shadow of a spaceship traveling on an (almost) straight line from KIC8462852 to Earth. The slow continuous dimming results from the increase of the apparent size of the approaching ship while Earth/Kepler is in the penumbra. The irregular dips h…
How can a ship 100 km in diameter cause any significant dimming of a star, which is 21,980,000 km in diameter? It would have to be pretty close to here and lined up just so perfectly. Why even assume it's a spaceship and not an asteroid or a rogue planet?
> Why even assume it's a spaceship and not an asteroid or a rogue planet?
Specifity bias. It "feels" more probable to have object going here because someone send it here, than to just have object going here.