Are UAPs/UFOs finally being taken seriously?

[Moontanman]

9 hours ago, exchemist said:

“Fictional habitats”

The first three are scientifically accurate portrayals of what is possible with our current technology. The others were indeed fictional but I did point that out. The fictional habitats were inspired by the possible reality of the others. We, as a species, need to dream, need inspiration, the fictional habitats may not be possible, the Niven Ring is definitely not possible but is a concept taken to its absolute limit. A simple can shaped object a few kilometers across and rotating for artificial gravity on its inside surface is well within the realms of possibility and is the only practical way to generate artificial gravity we know of.  

9 hours ago, exchemist said:

“Fictional habitats”

 

1 hour ago, dimreepr said:

Indeed, Ultimately it's a message in a bottle, if the bottle is properly corked.

For instance, as previously discussed, we've been sending out radio waves for X number of year's, none of which is discernable by Voyager, because the universe is full of noise...

 

1 hour ago, Genady said:

Our other great strength is ability to distinguish between imagination and reality. It is not a good sign when this ability is compromised.

 

2 hours ago, StringJunky said:

If one reads about something that has a basically nebulous level of evidence too much, one can end up believing it. The brain has a fantastic capacity for filling in the gaps in ways that may appear plausible, but ultimately don't stand up to scrutiny. Imagination is our great strength, but it is also a vulnerability if it's not checked.

I think there are many reasons planets would not be in demand and possibly ignored completely except as raw materials. Artificial habitats make much more sense. Millions of times the surface area of the Earth could be created using artificial habitats like O'Neill Cylinders , Stanford Torus , McKendree Cylinders  or just can shaped shaped habitats lighted from the inside rotated for artificial gravity and even have natural esque type habitats on the inner surface of these objects.

These or other artificial habitats could be manipulated to the heart's content of who ever creates them and only have familiar life forms on board.  

Problems would be encountered on real planets.

Planets would have problems ranging from viri to bacteria to fungus but more likely the possibility of environmental poisons like trace elements, too much of some minor gas in the atmosphere or too much environmental toxins like mercury or arsenic or some other poison that would affect them we don't know of. Life is amazingly well evolved to fit its habitat and colonising a strange hut natural world would be fraught by hazards an artificial habitat would not have to worry about.  

Is this better? 

[TheVat]

29 minutes ago, Moontanman said:

We, as a species, need to dream, need inspiration, the fictional habitats may not be possible, the Niven Ring is definitely not possible but is a concept taken to its absolute limit. A simple can shaped object a few kilometers across and rotating for artificial gravity on its inside surface is well within the realms of possibility and is the only practical way to generate artificial gravity we know of.  

I remember feeling a sad twinge when I learned that the Niven Ring wasn't practical - I think it was from an interview with Larry himself where he mentioned all the engineers who had contacted him over the years, alerting him to Ringworld's inherent instability.  Given that the Dyson Shell is also a no-go, that leaves the Dyson Swarm as the most viable of the large-scale builds.  I think there's been speculation as to their visibility to large telescopes, and how difficult it might be to spot telltales of such.  An unusually bright IR spectral profile might be one indicator.

The question of can habitats, for widespread use, might also focus on biosphere engineering problems.  Artificial ecosystems might prove really hard to maintain (natural ones are certainly proving to be pretty fragile) and some species might have beliefs that reject them.  Or longterm buffers against hard radiation might be impossible in some stellar systems without a planetary magnetic field and thick atmosphere.  So many unknowns at present.

[Moontanman]

1 hour ago, TheVat said:

I remember feeling a sad twinge when I learned that the Niven Ring wasn't practical - I think it was from an interview with Larry himself where he mentioned all the engineers who had contacted him over the years, alerting him to Ringworld's inherent instability.  Given that the Dyson Shell is also a no-go, that leaves the Dyson Swarm as the most viable of the large-scale builds.  I think there's been speculation as to their visibility to large telescopes, and how difficult it might be to spot telltales of such.  An unusually bright IR spectral profile might be one indicator.

As far as I know no potential dyson Swarms have been detected but if controlled fusion is possible th eneed for a dyson swarm evaporates.  

1 hour ago, TheVat said:

The question of can habitats, for widespread use, might also focus on biosphere engineering problems.  Artificial ecosystems might prove really hard to maintain (natural ones are certainly proving to be pretty fragile) and some species might have beliefs that reject them.  Or longterm buffers against hard radiation might be impossible in some stellar systems without a planetary magnetic field and thick atmosphere.  So many unknowns at present.

An artificial biosphere might require the occasional "topping up" of volities and trace elements. The problems really present when you are trying to maintain a biosphere over very long time frames. 

Radiation can be controlled by placing your habitat inside a shell constructed of the waste materials left over after constructing your habitat, a thick non rotating ice shell should do quite well and we can generate quite powerful magnetic fields as well. 

[swansont]

3 hours ago, Moontanman said:

Radiation can be controlled by placing your habitat inside a shell constructed of the waste materials left over after constructing your habitat, a thick non rotating ice shell should do quite well

The heat has to escape somehow. Making the outer later be ice just makes the interior hotter, at the cost of a lot of energy.

 

3 hours ago, Moontanman said:

and we can generate quite powerful magnetic fields as well. 

Which has no effect on the emission EM radiation 

[Moontanman]

20 minutes ago, swansont said:

The heat has to escape somehow. Making the outer later be ice just makes the interior hotter, at the cost of a lot of energy.

??? I was speaking about how to protect the inhabitants from radiation in space. How is using scraps material to but a shell around the habitat a cost of a lot of energy? 

20 minutes ago, swansont said:

 

Which has no effect on the emission EM radiation 

I wouldn't expect it to, I was speaking about the problem of particle radiation in space.  

[swansont]

1 hour ago, Moontanman said:

??? I was speaking about how to protect the inhabitants from radiation in space. How is using scraps material to but a shell around the habitat a cost of a lot of energy? 

You might notice I was referring to the ice layer you suggested, which won’t work, since the interior heat has to escape the container.

 

1 hour ago, Moontanman said:

I wouldn't expect it to, I was speaking about the problem of particle radiation in space.  

That wasn’t clear, and I don’t agree that we can easily generate strong magnetic fields on the scale necessary. We can generate strong fields on a scale of several meters. 

[Moontanman]

1 hour ago, swansont said:

You might notice I was referring to the ice layer you suggested, which won’t work, since the interior heat has to escape the container.

You might notice the ice layer I suggested had nothing to do with stopping interior heat from escaping. 

1 hour ago, swansont said:

 

That wasn’t clear, and I don’t agree that we can easily generate strong magnetic fields on the scale necessary. We can generate strong fields on a scale of several meters. 

If we used ice to protect the inner rotating structure from radiation w wouldn't need the magnetic field. 

[mistermack]

You two seem to be talking at cross purposes. 

I agree with Moontanman that waste materials, or stores can be used on the outside of a giant space living module to absorb harmful rays. Once you get over the problem of sourcing heavy materials from space rather than Earth, then it should be easy enough to design effective protection. 

I don't get why the protection can't rotate along with the living area though. Wouldn't it be fiendishly complicated, to have a spinning living module, inside a non-rotating shield ?

[NTuft]

7 hours ago, Moontanman said:

I was speaking about how to protect the inhabitants from radiation in space.

Boron nitride.

[Moontanman]

9 hours ago, mistermack said:

You two seem to be talking at cross purposes. 

I agree with Moontanman that waste materials, or stores can be used on the outside of a giant space living module to absorb harmful rays. Once you get over the problem of sourcing heavy materials from space rather than Earth, then it should be easy enough to design effective protection. 

I don't get why the protection can't rotate along with the living area though. Wouldn't it be fiendishly complicated, to have a spinning living module, inside a non-rotating shield ?

Having the protection spinning causes some problems. its mass for one and it's strength or lack thereof. Ice isn't exactly a strong material for structural use and using using it stationary precludes having to stick the chunks together. Not much more strength than a rubble pile possibly held loosely in place by a light structure of some common metal like aluminum? 

The habitat itself would be made principally of carbon instead of metals. Much stronger and lighter, and possibly more available in kuiper belt objects than metals although this might not apply if the habitat was made of asteroidal material and in that case even the waste material would be rock instead of ice.  

If I remember correctly there is also the problem of countering the rotation of the of the habitat. In some of the versions this is countered by having twin cylinders rotating opposite each other. I'm not sure how important this would be.    

8 hours ago, NTuft said:

Boron nitride.

Wouldn't this material be limited due to borons rarity? 

[swansont]

14 hours ago, Moontanman said:

You might notice the ice layer I suggested had nothing to do with stopping interior heat from escaping. 

Only if you completely ignore the laws of thermodynamics.

[NTuft]

1 hour ago, Moontanman said:

Wouldn't this material be limited due to borons rarity? 

I am not up on this thread, and if the discussion has gone towards sourcing materials locally I suppose that's what you're saying?
Boron, California mine operations

Quote

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I think there is another large natural deposit in Turkey.

[Moontanman]

3 hours ago, swansont said:

Only if you completely ignore the laws of thermodynamics.

This thread has moved away from detecting an alien space habitat by it's IR emissions. Currently it is discussing the viability of such habitats pertaining to protecting the inhabitants from space radiation coming in from outside the habitat. Preventing IR radiation from escaping is not relevant and such escape would occur no matter what the habitat was made of. In fact getting rid of waste heat might very well be a problem in the vacuum of space hence my idea of detecting such objects via their IR emissions which is not what we are currently talking about. 

2 hours ago, NTuft said:

I am not up on this thread, and if the discussion has gone towards sourcing materials locally I suppose that's what you're saying?
Boron, California mine operations

I think there is another large natural deposit in Turkey.

Yes, we are talking sourcing materials locally in the kuiper belt or asteroid belt. Also boron suffers from being rare in the universe at large as well. 

Edited April 2, 2023 by Moontanman

[swansont]

1 hour ago, Moontanman said:

This thread has moved away from detecting an alien space habitat by it's IR emissions. Currently it is discussing the viability of such habitats pertaining to protecting the inhabitants from space radiation coming in from outside the habitat. Preventing IR radiation from escaping is not relevant and such escape would occur no matter what the habitat was made of. In fact getting rid of waste heat might very well be a problem in the vacuum of space hence my idea of detecting such objects via their IR emissions which is not what we are currently talking about. 

We’re talking about the feasibility of encasing something in ice as a radiation shield, and I’m telling you that you’d bake everything inside if you did that. They wouldn’t die from radiation but they’d be just as dead. It’s not a viable solution.

[mistermack]

17 minutes ago, swansont said:

We’re talking about the feasibility of encasing something in ice as a radiation shield, and I’m telling you that you’d bake everything inside if you did that. They wouldn’t die from radiation but they’d be just as dead. It’s not a viable solution.

I've never heard of anyone worrying about shedding heat on a space station. Surely it's pretty simple to pump any excess heat through external radiators, if it was a problem? It could be radiated away or stored as a hot fluid in an insulated container. 

6 hours ago, Moontanman said:

Ice isn't exactly a strong material for structural use and using using it stationary precludes having to stick the chunks together. Not much more strength than a rubble pile possibly held loosely in place by a light structure of some common metal like aluminum? 

But this is ice frozen to minus 250 or more. On some distant solar system bodies there are mountains made of water ice, it behaves like rock does here on Earth, so you would think that supporting it's own weight, in artificial gravity of not much more than 1g would not be a problem. If necessary, it could be reinforced with metal, like concrete here on Earth.

[Moontanman]

39 minutes ago, swansont said:

We’re talking about the feasibility of encasing something in ice as a radiation shield, and I’m telling you that you’d bake everything inside if you did that. They wouldn’t die from radiation but they’d be just as dead. It’s not a viable solution.

You would have to have radiators no matter what it was made of wouldn't you? 

[mistermack]

6 minutes ago, Moontanman said:

You would have to have radiators no matter what it was made of wouldn't you? 

You could use the heat to generate electricity with some fairly simple kit. 

[swansont]

7 minutes ago, mistermack said:

I've never heard of anyone worrying about shedding heat on a space station. Surely it's pretty simple to pump any excess heat through external radiators, if it was a problem? It could be radiated away or stored as a hot fluid in an insulated container. 

In which case the craft is not encased in ice, and the radiators would tend to melt the ice.

But yes, shedding heat is generally a problem - since all you have is radiation - and it gets worse as the craft gets larger (volume grows faster than surface area). This is especially an issue when they are warmed by the sun. Radiating fins that are near each other don’t work well, since they “see” each other and absorb almost as much as they emit. i.e. two such fins are only marginally better than one, not twice as good. Ice by itself could only radiate a few hundred watts per square meter. (a perfect radiator would emit ~300 W at most at 273K)

13 minutes ago, mistermack said:

You could use the heat to generate electricity with some fairly simple kit. 

To extract electrical energy you have to…wait for it…reject heat.

 

23 minutes ago, Moontanman said:

You would have to have radiators no matter what it was made of wouldn't you? 

Yes. But you wouldn’t be limited to the radiators being below the freezing point of water, and radiated power varies as T^4. Something at the boiling point of water radiates ~3.5 as much power as at the freezing point, all else being the same

[mistermack]

5 minutes ago, swansont said:

In which case the craft is not encased in ice, and the radiators would tend to melt the ice.

But you only need to shield living and working areas. And the ice can be encased in a reflective skin. 

7 minutes ago, swansont said:

But yes, shedding heat is generally a problem - since all you have is radiation - and it gets worse as the craft gets larger (volume grows faster than surface area).

Radiation in space can be pretty effective, as the radiators don't need to be robust or bear their own weight so you can make them very thin with a great surface area. And volume doesn't equate to greater heat generation. You will only generate small amounts from equipment, and obviously none from space heating, if you are having to dump heat. In any case, the living volume probably wouldn't be spherical or cylindrical, more likely ring shaped, with more surface area than a sphere or cylinder. 

20 minutes ago, swansont said:

Radiating fins that are near each other don’t work well, since they “see” each other and absorb almost as much as they emit.

Not if they are thin and flat and all in the same plane. And the point about space is that there is a lot of it. You can give a radiator an enormous surface area that would be impossible here on Earth. 

One problem would be getting cooling fluids from a rotating module to non-rotating radiators. I'm pretty sure you could get over that, maybe by having the fluids exit and re-enter along the axis of rotation. 

Since rotation is likely to be not much more than 1 rpm, I think it could be done ok. 

 

[swansont]

22 minutes ago, mistermack said:

But you only need to shield living and working areas. And the ice can be encased in a reflective skin. 

Reflective skin makes the ice less efficient at radiating, and this is basically an acknowledgement that the original claim won’t work. I agree, but that was the limit of my objection.

22 minutes ago, mistermack said:

Radiation in space can be pretty effective, as the radiators don't need to be robust or bear their own weight so you can make them very thin with a great surface area. And volume doesn't equate to greater heat generation. You will only generate small amounts from equipment

Really? Mechanical equipment is not all that efficient, so it generates a lot of waste heat, and for electrical equipment, most of it shows up as resistive losses. A computer, for example, that draws 300 W needs to shed all of that. Where else does it go? Other than a fan, which generates even more heat (fans heat, not cool, the air), there are no moving parts. No kinetic energy, no mechanical work. It all eventually ends up as waste heat.

 

22 minutes ago, mistermack said:

and obviously none from space heating, if you are having to dump heat. In any case, the living volume probably wouldn't be spherical or cylindrical, more likely ring shaped, with more surface area than a sphere or cylinder. 

And the parts that face each other just trade radiated energy, as I mentioned, and that doesn’t contribute to the cooling. Only the surface area that faces deep space lets you radiate heat.

22 minutes ago, mistermack said:

Not if they are thin and flat and all in the same plane. And the point about space is that there is a lot of it. You can give a radiator an enormous surface area that would be impossible here on Earth. 

Yes. But that gets away from the original premise.

Basically you’re arguing that the premise isn’t flawed if you change the premise. Sure. 

 

 

[TheVat]

27 minutes ago, swansont said:

To extract electrical energy you have to…wait for it…reject heat.

 

Seems like space habitats follow the rule of all real estate: location, location, and location. 

Particle radiation (which is the major form of ionizing radiation that space habitats must fend off somehow) will be varying considerably between an EO colony, a Lagrange point like L4 and somewhere in the Kuiper belt.  It's my understanding that GCR (galactic cosmic rays) is the dominant source for daily exposure, while SEP (solar energetic particles) are episodic, like bad weather, coming from CMEs that would happen to come the colony's way.  And their threat would be far less in the Kuiper Belt.   

Ergo, an EO colony would have magnetosphere protection (a MEO, Medium Earth Orbit, e.g. would lie in a safe zone between the inner and outer Van Allen belts), a Lagrange colony (beyond the magnetosphere) would need SEP storm shelters, and also general GCR shielding, and a Kuiper condo would need just the GCR shielding.  A plus for the Kuiper colony, is that they have an easier waste heat dump, which I'd think make shielding problems easier.  

But really it seems like the orbital colony, inside a magnetosphere, has the simplest situation, although other complexities arise I'm sure.

[mistermack]

I just found this about the ISS and heat regulation on it : 

The radiators are much as I guessed, large and thin and in the same plane. They are obviously up to the job. 

I wouldn't think that a less intensive living module would need so much cooling, as you wouldn't have such tightly packed equipment in such a small space. 

In a bigger unit, you could have air ducts passing through the solid shielding, warming the outer surface enough to radiate quite a lot of heat independent of radiators.

56 minutes ago, swansont said:

Basically you’re arguing that the premise isn’t flawed if you change the premise. Sure.

Enclosing absolutely everything in ice was never my premise, and it was obviously suggested to combat radiation to protect humans, so I think you're over-stressing the original suggestion a bit. Having bits and pieces external to the shielding just makes common sense to me. 

If the living area of the station was ring shaped, you could have the ring shielded, and all sorts of other stuff in the centre, like radiative panels. If things were located close to the axis of rotation, the effect of artificial gravity would be very low, so they could be made of thin lightweight materials.

[swansont]

18 hours ago, mistermack said:

The radiators are much as I guessed, large and thin and in the same plane. They are obviously up to the job. 

But they are necessary, meaning the modules don’t shed enough heat on their own.

 

18 hours ago, mistermack said:

I wouldn't think that a less intensive living module would need so much cooling, as you wouldn't have such tightly packed equipment in such a small space. 

The ISS is for astronauts who live a pretty spartan existence, and have things delivered to them, something that wouldn’t happen with a remote habitat  

 

18 hours ago, mistermack said:

In a bigger unit, you could have air ducts passing through the solid shielding, warming the outer surface enough to radiate quite a lot of heat independent of radiators.

The heat from that surface would also go inward. 

[Moontanman]

22 hours ago, swansont said:

In which case the craft is not encased in ice, and the radiators would tend to melt the ice.

But yes, shedding heat is generally a problem - since all you have is radiation - and it gets worse as the craft gets larger (volume grows faster than surface area). This is especially an issue when they are warmed by the sun. Radiating fins that are near each other don’t work well, since they “see” each other and absorb almost as much as they emit. i.e. two such fins are only marginally better than one, not twice as good. Ice by itself could only radiate a few hundred watts per square meter. (a perfect radiator would emit ~300 W at most at 273K)

To extract electrical energy you have to…wait for it…reject heat.

 

Yes. But you wouldn’t be limited to the radiators being below the freezing point of water, and radiated power varies as T^4. Something at the boiling point of water radiates ~3.5 as much power as at the freezing point, all else being the same

You assume the radiators would have to be near or in contact with the ice? Ok, lets use silicate debris in stead. Even Kuiper belt objects wouldn't be made of exclusively ice nor would all asteroids be made exclusively of silicates. I am sure there are or will be engineering work arounds for these heat radiation problems. 

This does direct back to my original premise of detecting aliens via their heat signatures or do we assume they have Clark tech that negates the issue? Heat radiation is a well known problem for space craft and many designs of nuclear powered craft do indeed take this into account. 

[swansont]

2 hours ago, Moontanman said:

You assume the radiators would have to be near or in contact with the ice?

I took your statement at face value.

The secondary point is that broad claims aren’t good enough - details matter. Space travel is not trivial.

2 hours ago, Moontanman said:

This does direct back to my original premise of detecting aliens via their heat signatures or do we assume they have Clark tech that negates the issue? Heat radiation is a well known problem for space craft and many designs of nuclear powered craft do indeed take this into account. 

If you assume Clark tech you run the risk of it being science fiction. You still have to follow the laws of physics.