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 AlmightyWalrus wrote:
Why would infrared allow a Dyson Sphere to be seen? Isn't the point that it absorbs ALL the energy coming from the star, including IR?

The structure would reradiate infrared radiation and would in fact increase the amount of infrared radiation beyond what the star would normal give off (assuming that it is a Sun-like star and the structure was made of materials similar to those available to humans). Freeman Dyson wrote about it in his paper back in the 1960s.

 ScootyPuffJunior wrote:

 AlmightyWalrus wrote:
Why would infrared allow a Dyson Sphere to be seen? Isn't the point that it absorbs ALL the energy coming from the star, including IR?

The structure would reradiate infrared radiation and would in fact increase the amount of infrared radiation beyond what the star would normal give off (assuming that it is a Sun-like star and the structure was made of materials similar to those available to humans). Freeman Dyson wrote about it in his paper back in the 1960s.

And Mr Charisma, AKA, Lieutenant Commander Geordi La Forge, bored us to death about Dyson Spheres in an episode of Star Trek TNG

 ScootyPuffJunior wrote:
It should be noted that astronomers have studied vast swaths of the sky with infrared telescopes (which would allow the star inside the sphere to be seen) and have yet to find one.

I think there are some candidates. Or at least observations which haven't been completely ruled out.

You have to wonder if it's a realistic idea though. Building a Dyson sphere would require quite a lot of energy and advanced technology. Any civilization capable of building one, might be well beyond the point where they actually need one.

 Smacks wrote:

 ScootyPuffJunior wrote:
It should be noted that astronomers have studied vast swaths of the sky with infrared telescopes (which would allow the star inside the sphere to be seen) and have yet to find one.

I think there are some candidates. Or at least observations which haven't been completely ruled out.

You have to wonder if it's a realistic idea though. Building a Dyson sphere would require quite a lot of energy and advanced technology. Any civilization capable of building one, might be well beyond the point where they actually need one.

Yeah. They would definitely be useful, but the question is if you could get your civilization to stick around long enough to actually build it. It would realistically take, even with advanced technology, hundreds of thousands of years to build one. You'd also need to have good interstellar travel as you're not going to have enough materials in just one system. You're gonna have to plunder hundreds or even thousands of systems to get the materials to make the structure alone.

So really I think its more that they'd be way too much of a time investment even if it would be incredibly useful. And if you have good interstellar travel why not just colonize/terraform other planets instead of taking thousands of generations to build one of these things?

I don't think they can even be built. The gravity of the star would pull on it and ultimately cause it to collapse from stress. You could spin it and that would help at the equator but not the poles. Also, if you spin it, you can't have the whole thing be habitable as air would move toward the equator and you'd wind up with the pressures you see on Jupiter or even greater.

A ring would have a better chance but the lack of magnetic field protection presents other problems.

 Smacks wrote:

 ScootyPuffJunior wrote:
It should be noted that astronomers have studied vast swaths of the sky with infrared telescopes (which would allow the star inside the sphere to be seen) and have yet to find one.

I think there are some candidates. Or at least observations which haven't been completely ruled out.

You have to wonder if it's a realistic idea though. Building a Dyson sphere would require quite a lot of energy and advanced technology. Any civilization capable of building one, might be well beyond the point where they actually need one.

Essentially this. Currently unknown space magic aside, the kind of engineering and material miracles that would be required to make a stable structure enveloping a star would require a technology level so high that anything that could actually do it would have much more practical and applicable things to do with it.

It's kind of like, nowadays, we can construct and make work several of Da Vinci's flying machines, but if we actually want to fly, we build a jet.

 Breotan wrote:
I don't think they can even be built. The gravity of the star would pull on it and ultimately cause it to collapse from stress. You could spin it and that would help at the equator but not the poles. Also, if you spin it, you can't have the whole thing be habitable as air would move toward the equator and you'd wind up with the pressures you see on Jupiter or even greater.

A ring would have a better chance but the lack of magnetic field protection presents other problems.

The gravity from the sun is pretty much entirely cancelled out by the solar wind. You'd be building one of these fairly far out, after all. They're also designed not as habitats but for power generation, as you're capturing the entire output of the sun. Even if you are inhabiting it, as you've noted, you only need a thin belt along the equator to be usable, and you'd still have several billion times the surface area of Earth to play with.

 Laughing Man wrote:

 Breotan wrote:
I don't think they can even be built. The gravity of the star would pull on it and ultimately cause it to collapse from stress. You could spin it and that would help at the equator but not the poles. Also, if you spin it, you can't have the whole thing be habitable as air would move toward the equator and you'd wind up with the pressures you see on Jupiter or even greater.

A ring would have a better chance but the lack of magnetic field protection presents other problems.

The gravity from the sun is pretty much entirely cancelled out by the solar wind.

No. It really, truly does not. I don't know where you got this from. While the force of the solar wind can drive away particles of dust and such, anything larger remains and is only kept from plummeting into the Sun by angular momentum.

Theoretically, I would think that if you could build a sphere, you could also solve most of the inherent problems, or you would have long ago abandoned it.

 BlaxicanX wrote:

 Alpharius wrote:
So what are they saying they think it is then?

I imagine the "real scientist" guess at this point would be that it's "possibly something... we've maybe not seen before, maybe."

Because that's generally just how scientists articulate their guesses. And then they wonder why "people aren't interested in NASA anymore!"

EDIT- Ninja'd. heh.

Because most new discoveries in science consist of "huh, that's weird, I don't know why it did that."

 Grey Templar wrote:
Yeah. They would definitely be useful, but the question is if you could get your civilization to stick around long enough to actually build it. It would realistically take, even with advanced technology, hundreds of thousands of years to build one. You'd also need to have good interstellar travel as you're not going to have enough materials in just one system. You're gonna have to plunder hundreds or even thousands of systems to get the materials to make the structure alone.

A civilisation using Von Neumann probes could potentially get it built with a minimal level of starting resorces invested. Depending on system resources and how the probes were programmed, the production could be near exponential.

In terms of material requirements I think you are vastly overestimating what you would need. In addition, as energy supply increases, it becomes more attractive to use that energy to transform or create matter; though that would perhaps come later in the process.

Theoretically we could be well on the way to creating our own sphere in the next century with some smart engineering and programming.

 Easy E wrote:
Megastructures..... what the heck does that even mean in this story?

It means they used the wrong term and sensationalised a mundane astronomical finding.

 Orlanth wrote:

 Easy E wrote:
Megastructures..... what the heck does that even mean in this story?

It means they used the wrong term and sensationalised a mundane astronomical finding.

Pretty much.

Also, why couldn't it be a dyson swarm, or any other of the energy gathering structures around the sun. There are a multitude of our own theories of "megastructures" and alien life could conceive of more. Alternately....5th dimension/6th dimensional beings?

The reality is, that until we actually are able to observe the star directly, is a resounding "I don't actually know for sure, but it MIGHT be ET-made". There is still a multiude of casualities out there and physical effects that we might not even know about.

I still think it's space rocks. There are a lot of space rocks.

I still think it's space rocks. There are a lot of space rocks.

That is definitely a bit of an Occam's Razor for me. Solar systems by their inherent nature seem to have an awful lot of large celestial objects flying around that can block sunlight.

Or.....a massive fleet of alien ships blocking the sunlight!

In slightly unrelated news but still a bit of tongue in cheek for this thread:

The "ancient aliens" guy as a Centauri. that explains so much!

But where are his tentacles?

Hive Fleet Leviathan is on its way.