Dyson Sphere thread

[IG2007]

Think of the difficulty of putting satellites in close orbit around the Sun. Then, as you say, sending the energy back.

NASA has already sent a satellite in a close orbit around the Sun. According to wikipedia,

"The Parker Solar Probe is a NASA Space Probe launched in 2018 with the mission of making observations of the outer corona of the Sun. It will approach to within 9.86 solar radii from the center of the Sun, and by 2025 will travel, at closest approach, as fast as 690,000 km/h, or 0.064% the speed of light."

I doubt the investors would ever get their money back.

I have no doubt on it. Not only the investors, but many other people on Earth will get their money back.

 

[Catastrophe]

A probe observing is one thing. Long term functioning (regular servicing) working at high temperatures for long periods - melting or degradation of components. Not as easy as a few words on paper. Possible - yes. Practical - ?????

 

[IG2007]

Possible - yes. Practical - ?????

Well, practicality is a question indeed. But, you know, the magic of the present, is the science of the future.

 

[Catastrophe]

Well, practicality is a question indeed. But, you know, the magic of the present, is the science of the future.

Well said.

 

[Trevize62]

A true Dyson sphere is impossible to build, but we could find an acceptable substitute in a swarm of megastructures with dimensions between 5 and10 km.

 

[Catastrophe]

According to Wiki a Dyson Sphere "completely encompasses a star". May I remind you of the question on #1 Hi!This is the thread to discuss, how the Dyson sphere can be built, what difficulties are in doing so, and so on. My emphasis.

Has anyone worked out the volume/mass of a sphere of ?AU? 0.2, 0.4? 0.02? AU distant from the star, of thickness 1 metre (for example), not to mention how, and from what, it might be constructed.

Should we not get back to addressing the questioner's original post? My one word answer is impossible.

Cat

 

[IG2007]

Should we not get back to addressing the questioner's original post? My one word answer is impossible.

I agree that neither a Dyson Sphere nor a Dyson Swarm would be a viable economic solution to our problems. But I do really think that #49 would work very well.

 

[Catastrophe]

From #49:
"Because, you can make a dozen big satellites and put them in a close orbit around the sun and when they are full, you can send a laser beam to another satellite which would be orbiting Mercury, which will then send it to another satellite in Venus, which will send it to a satellite orbiting Earth and we can manually take that energy from that satellite"
Why the jumping around from planet to planet? Looking at the orbits, sometimes the inner planets are on the opposite side of the Sun. Then direct to Earth would be much nearer.

Cat

 

[IG2007]

From #49:
Then direct to Earth would be much nearer.

Cat

How is Earth more near to the Sun than Mercury is?

 

[Catastrophe]

How is Earth more near to the Sun than Mercury is?

IG. When Mercury is on the opposite side of the Sun to the Earth (Earth-Sun-Mercury) it is at its furthest i.e., Earth is furthest it can get from Mercury. Earth is not nearer the Sun than Mercury - the Earth-Sun-Mercury distance is the greatest it can be. Of course, Earth and Mercury are individually within their normal distance from the Sun parameters.
You could imagine the real situation where Mercury is between Earth and Sun at the same time as Venus is on the opposite side of the Sun i.e., Earth Mercury-Sun-Venus. In that case it would not be quickest to go from Mercury to Venus to Earth, but directly Mercury to Earth.

As I posted:
"Looking at the orbits, sometimes the inner planets are on the opposite side of the Sun. Then direct to Earth would be much nearer."
In this case direct Mercury to Earth.

Cat

 

[IG2007]

Well, Cat, now I understand what you mean to say. IMO, we should let the guys who do the thing (if someone even does the thing) to decide for themselves. I mean to say, for example, a direct laser beam can be sent from Sun to Earth only when there are no obstructions (that is, planets or asteroids or comets or anything else). What do you think?

 

[Catastrophe]

IG, Don't see why not. Is the laser technology available? Cat

 

[Creator223]

No, it isn't.Lasers by themselves may lose LOTS of energy.

 

[Creator223]

probably it is possible to create some kind of beacons and transfer energy in short laser pulses from beacon to beacon.

 

[Lightspeed]

To keep our Mercury issue on topic, can we take Mercury as a possible location for mining - the energy possibly (??) being supplied by a Dyson sphere. Of course, if this is not possible, alternate energy must be provided.

Cat

I was thinking here.
Having humans in Mercury would be more trouble than what is worth, so perhaps we should use robots instead.

As for ore refining...I am not an expert, but could we use the high temperature of light around Mercury's orbit to 'pre-refine' the iron?

Ah. I hope I am not doing something bad by answering here. I saw now this topic was last answered in the last year, but I felt it could be relevant.

 

[Catastrophe]

I, personally, cannot see a problem in replying to an oldish thread (10 months) as long as it is not being used to divert or otherwise negatively impinge on the thread. The previous post #64 was by the OP (Creator223), who might like to express an opinion. I stand open to correction.

Lightspeed, my answer to your post will follow a common theme of mine. It is all very easy to do this or that, but practical solutions to problems arising should, imho, be addressed.

Yes, the high temperature on Mercury's Sun side would be useful, but don't melt the robots. Or the spacecraft that deliver them to Mercury.

Cat

 

[Catastrophe]

Some information relative to the Mercury temperature/metals question:

“It is understood that the sunny side may reach temperatures of 750 to 800 degrees F., [400-427 degrees C] while the night time temperature plummets to nearly -330 degrees F.”
from:
https://www.weather.gov/fsd/mercury#:~:text=The average temperature on Mercury,we observe from the Earth.
Mercury's surface temperatures are both extremely hot and cold. Because the planet is so close to the Sun, day temperatures can reach highs of 430°C..

Iron/Melting point 1,538 °C
The melting point of steel ranges from 1371-1540°C..
Seems iron/steel would be OK, but a lot of plastics might melt.

At a standard atmospheric pressure (1 ATM), blood boils at approximately the same temperature as water: around 100 degrees Celsius, but of course at the lower atmospheric pressure on Mercury would considerably lower the boiling point. In any case, even taking this into consideration blood would boil on the sunny side of Mercury. Robots would be essential, but they would have to be delivered without human intervention. Including humans on the ship would require a lot of thermal insulation.

Any robots used would have to withstand the huge temperature range quoted above, and the absence of atmosphere.

My estimation (imho) of any advantage in utilising the highest temperatures on Mercury would be that it would not be worth the trouble. Lower temperature sites are available, but there would still be the huge temperature differential (low temperatures during dark times) to be considered.

It might be possible to transfer energy from hotter regions, but this could be am expensive procedure, especially in putting in place.

Cat

 

[Lightspeed]

Some information relative to the Mercury temperature/metals question:

“It is understood that the sunny side may reach temperatures of 750 to 800 degrees F., [400-427 degrees C] while the night time temperature plummets to nearly -330 degrees F.”
from:
https://www.weather.gov/fsd/mercury#:~:text=The average temperature on Mercury,we observe from the Earth.
Mercury's surface temperatures are both extremely hot and cold. Because the planet is so close to the Sun, day temperatures can reach highs of 430°C..

Iron/Melting point 1,538 °C
The melting point of steel ranges from 1371-1540°C..
Seems iron/steel would be OK, but a lot of plastics might melt.

At a standard atmospheric pressure (1 ATM), blood boils at approximately the same temperature as water: around 100 degrees Celsius, but of course at the lower atmospheric pressure on Mercury would considerably lower the boiling point. In any case, even taking this into consideration blood would boil on the sunny side of Mercury. Robots would be essential, but they would have to be delivered without human intervention. Including humans on the ship would require a lot of thermal insulation.

Any robots used would have to withstand the huge temperature range quoted above, and the absence of atmosphere.

My estimation (imho) of any advantage in utilising the highest temperatures on Mercury would be that it would not be worth the trouble. Lower temperature sites are available, but there would still be the huge temperature differential (low temperatures during dark times) to be considered.

It might be possible to transfer energy from hotter regions, but this could be am expensive procedure, especially in putting in place.

Cat

Hm, those are indeed factors I didn't think. Well, perhaps better would be to think about the machine that they would probably be using...the main issue is the temperatures, in a place without an atmosphere, could perhaps...a mirror be enough to make the surface at least 'workable'? With that, at least you cut the expense with thermal coating for anything on the surface...

Now issue is that the idea is to make a big mirror that might be impractical...

 

[Catastrophe]

Lightspeed, how exactly are you going to use this mirror? . . . . . . how big does it need to be? . . . . . . and how are you going to make/transport it?

Cat

 

[Lightspeed]

Lightspeed, how exactly are you going to use this mirror? . . . . . . how big does it need to be? . . . . . . and how are you going to make/transport it?

Cat

Honestly? Well, we would need the planet to be in a reasonable temperature to extract its resources, so perhaps use the mirror to deflect part of the sunlight and make the surface less hellish? Since we are assuming humans would be living in space for a time, perhaps industries located in space? Perhaps extracted from near Earth asteroids or the belt.

Thing on making it? The thing is if there is enough silicates to do it...as for transport? Perhaps ships using carefully laid routes...although one must expect anything...I even wonder if ships could use the planets' gravitational fields to cut fuel expenses. Although maybe a combination of sky hooks and others might cheapen costs.

 

[Catastrophe]

Lightspeed, that is a good start. However, I am not yet convinced.

Would you please estimate the weight (on Earth) of the mirror, where precisely it should be situated, and how its position is to be maintained (presumably some orbit). I am asking the Earth weight because, presumably, the silica will originate on a planet comparable to Earth in size, so this will give an indication of the amount of silica to be transported to its ultimate destination, and the amount of fuel required.

It's not as simple as it might appear at first sight, is it?

Cat

 

[Senthil]

Wiki Dyson Sphere

Quote
A Dyson sphere is a hypothetical megastructure that completely encompasses a star and captures a large percentage of its power output. The concept is a thought experiment that attempts to explain how a spacefaring civilization would meet its energy requirements once those requirements exceed what can be generated from the home planet's resources alone. Only a tiny fraction of a star's energy emissions reaches the surface of any orbiting planet. Building structures encircling a star would enable a civilization to harvest far more energy.
Quote

My emphasis.

Cat

Wondering how dyson sphere is possible cover fully/partially or can be detected?. Say for instance, in our solar system, sun is 99.8 % mass. So even if entire solar system is dismantled and used for building Dyson sphere around sun, it will be extremely small. How can someone detect at all??

 

[Catastrophe]

I did not say that. I posted the quote from Wiki. Ask them.


Dyson sphere - Wikipedia
https://en.wikipedia.org › wiki › Dyson_sphere

A Dyson sphere is a hypothetical megastructure that completely encompasses a star and captures a large percentage of its solar power output.
‎Dyson spheres in popular culture · ‎Freeman Dyson · ‎Tabby's Star · ‎Kardashev scale




Quoted by:

Cat

 

[billslugg]

Dyson sphere converts visible light to electricity on its front side facing the Sun. Unavoidable losses to heat must be radiated from the back side facing away from the Sun. The ratio of visible light to infrared light is understood for each type of star. If an excess of infrared light is found for a particular type of star, the inference is that a good portion of the visible is being intercepted and converted to other uses. A dust cloud around the star could do the same thing so such an excess is not an certain indication of intelligence.

 

[Catastrophe]

"A Dyson sphere is a hypothetical megastructure that completely encompasses a star"

OP's question was completely answered by Wolfshadw in post #2.
One might only ask "what" and "how" in relation to assembling this material, but those questions are already made redundant.

Cat