- #1
zuz
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I have heard one theory that Tabbys star dims is due to an alien megastructure. Where would they get the raw materials to build such a large object?
Is Tabby's Star Dimming Due to an Alien Megastructure?
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- Thread starter zuz
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Discussion Overview
The discussion centers around the potential causes of the dimming of Tabby's Star, particularly the theory that it may be due to an alien megastructure. Participants explore various hypotheses, including the feasibility of constructing such a structure and alternative explanations involving dust or debris. The conversation touches on theoretical constructs like Ringworlds and Dyson spheres, as well as the implications of creating a "blue dwarf" star.
Discussion Character
- Exploratory
- Debate/contested
- Conceptual clarification
Main Points Raised
- Some participants propose that the materials for an alien megastructure could be sourced from astronomical bodies within the star system or nearby systems.
- One participant suggests that minimal material is needed to block sunlight, citing examples from our solar system's asteroid belt.
- Another participant expresses skepticism about the alien megastructure theory, questioning the necessity of such a structure if resources and energy were available.
- There is a suggestion that the dimming of Tabby's Star might be due to a distribution of mass, such as dust or debris, rather than an alien construct.
- Several participants discuss theoretical constructs like Ringworlds and Dyson spheres, speculating on their potential purposes and implications.
- One participant introduces the idea of a "blue dwarf" star and questions its efficiency as a power source compared to a Dyson sphere.
- Another participant provides a brief overview of blue dwarfs, stating that they do not go supernova and can only produce helium, while also asserting that Tabby's Star will never become a blue dwarf.
- There are multiple references to the speculative nature of the discussion, with some participants urging a return to more grounded topics.
Areas of Agreement / Disagreement
Participants generally express skepticism about the alien megastructure theory, but there is no consensus on the exact cause of the dimming of Tabby's Star. Multiple competing views and speculative ideas remain present throughout the discussion.
Contextual Notes
Some claims about the feasibility of constructing megastructures and the nature of blue dwarfs depend on specific assumptions and definitions that are not fully explored in the discussion. The conversation also includes unresolved questions about the implications of creating stars and the processes involved.
- #2
Drakkith
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Presumably from the astronomical bodies (planets, moons, asteroids, etc) within the star system or from other nearby star systems.
- #3
stefan r
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Hold up a sheet of aluminum foil. How much dimmer is your laptop screen?
You only need a few microns of material to block sunlight. In some cases a few nanometers.
Our solar system has iron based asteroids. The "low iron content" meteors that we find on Earth have more iron and nickle than anything else. If you take a cube that is 1 km on a side and roll it into sheets with one micron thickness then you have a surface that is 1 billion km2. More area than Earth.
Wikipedia says the inner belt in the solar system has over 750,000 asteroids larger than 1 kilometer. in order to block 20% of an F star's light you need more like 1012km2 That requires more like a 10 km scale asteroid. We know of around 10.000 of them in our inner belt.
You only need a few microns of material to block sunlight. In some cases a few nanometers.
Our solar system has iron based asteroids. The "low iron content" meteors that we find on Earth have more iron and nickle than anything else. If you take a cube that is 1 km on a side and roll it into sheets with one micron thickness then you have a surface that is 1 billion km2. More area than Earth.
Wikipedia says the inner belt in the solar system has over 750,000 asteroids larger than 1 kilometer. in order to block 20% of an F star's light you need more like 1012km2 That requires more like a 10 km scale asteroid. We know of around 10.000 of them in our inner belt.
- #4
DaveC426913
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We don't quite yet know what exactly is dimming Tabby's star.
It is likely some distribution of mass - likely dust or debris - around the star, the configuration of which still eludes us.
"Alien megastructure" - while scientists have entertained it as a possibility - is pretty much at the very bottom of the list.
It is likely some distribution of mass - likely dust or debris - around the star, the configuration of which still eludes us.
"Alien megastructure" - while scientists have entertained it as a possibility - is pretty much at the very bottom of the list.
- #5
zuz
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I doubt the alien theory also. But if you had the resources and energy to build such a structure, why would you need it?
- #6
Ophiolite
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It is worth reflecting carefully on the meaning of the word alien.zuz said:
- #7
hmmm27
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zuz said:
Ringworld ? Zoetrope ? Maybe they're trying to make a "blue midget" by reflecting all the star's radiation back at it. Perhaps Von Neumanns have been collating a heavy asteroid belt into nice neat piles around lagrangian points for the last 20,000 years.
- #8
jim mcnamara
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This thread is off the rails a bit. Let's try General Discussion before we descend into total speculation. PF is not a good platform for making stuff up.
- #9
Borek
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hmmm27 said:
+Dyson sphere.
- #10
stefan r
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We should be able to make various models of dust engines. When a structure folds up it spirals down to the star. Once it gets hot it can unfold and blow out on the solar wind. Would be good for reaction mass.
- #11
szopaw
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hmmm27 said:
I'm trying to run with this idea and figure out what purpose would making a "blue dwarf" have. Could it produce heavy elements without going supernova like a heavy star? Would it be a more efficient power source that your garder variety Dyson sphere?
- #12
stefan r
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This is way off topic. Not sure if continuing is physics forums appropriate. It is in the lounge so...:
Here is a paper on blue dwarfs. There are no blue dwarfs observed today. Accepted models suggest that there will be many natural blue dwarfs eventually.
No, Blue dwarfs will only produce helium. Yes, blue dwarfs do not go supernova.
Tabby's star will never become a blue dwarf.
No. You are burning hydrogen either way. As a Shkadov thruster a blue dwarf would accelerate more than main sequence stars in the same spectral class.
It may be the least amount of mass needed to make a star that has both near solar luminosity and near solar temperature.
The blue dwarfs are most likely a byproduct. It is a way to dump large amounts of helium. You started with galaxy standard composition. The hydrogen went to someone, probably for energy. The metals became something else. There is a fair chance that collecting the metals was the motive for colonizing the cloud to begin with. Large amounts of helium is there and it is somewhat in the way. The manufactured blue dwarf has a purpose similar to the way piles of overburden have a purpose.
Here is a paper on blue dwarfs. There are no blue dwarfs observed today. Accepted models suggest that there will be many natural blue dwarfs eventually.
szopaw said:
No, Blue dwarfs will only produce helium. Yes, blue dwarfs do not go supernova.
Tabby's star will never become a blue dwarf.
szopaw said:
No. You are burning hydrogen either way. As a Shkadov thruster a blue dwarf would accelerate more than main sequence stars in the same spectral class.
It may be the least amount of mass needed to make a star that has both near solar luminosity and near solar temperature.
Under what circumstances we are "making stars"? In your giant molecular cloud you have thousands of solar mass. You collapse your cloud as you process it. You need to fling mass away from the cloud in order for it to continue collapsing. Which mass you eject will depend on what product the customer wants delivered.szopaw said:
The blue dwarfs are most likely a byproduct. It is a way to dump large amounts of helium. You started with galaxy standard composition. The hydrogen went to someone, probably for energy. The metals became something else. There is a fair chance that collecting the metals was the motive for colonizing the cloud to begin with. Large amounts of helium is there and it is somewhat in the way. The manufactured blue dwarf has a purpose similar to the way piles of overburden have a purpose.
- #13
szopaw
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stefan r said:
I had to re-check what type of star Tabby's star is, because I was absolutely 100% convinced it was a red dwarf.