Experimental device generates electricity from the coldness of the universe
phys.org
phys.org
Wouldn’t the infrared reflectivity of the parabola concentrate heat energy in to the focal point?
edit - have a go at pointing an infrared thermometer at an empty patch of sky on a clear night.
I thought that’s what we saw as per your instructions? I thought air (mostly nitrogen and oxygen) is mostly transparent to infrared radiation?
🞻 From the local surroundings. It will amplify the incoming radiation form space but that doesn't matter as space is cold.
We could start looking for cold spots that should be warm.
A truly advanced civilization wouldn't need that much energy (they would be very efficient), and certainly wouldn't need to "kidnap" a start for that.
A single digit percent of the Earth would need to be covered with solar panels with today's technology for our energetic consumption, I don't see why advanced civilizations would need let's say 10% of the energy of a star (let alone need to capture it)
It takes a lot of energy to make an omelette. Or a lot more energy to make a person-sized person.
https://en.wikipedia.org/wiki/Jevons_paradox
> In economics, the Jevons paradox (/ˈdʒɛvənz/; sometimes Jevons effect) occurs when technological progress or government policy increases the efficiency with which a resource is used (reducing the amount necessary for any one use), but the rate of consumption of that resource rises due to increasing demand.[1]
> In 1865, the English economist William Stanley Jevons observed that technological improvements that increased the efficiency of coal-use led to the increased consumption of coal in a wide range of industries. He argued that, contrary to common intuition, technological progress could not be relied upon to reduce fuel consumption.[4][5]
With enough energy crazy things are possible. Terraforming planets, human-lifespan interstellar travel, swarms of space habitats allowing everybody to have their own ecosystem changing to their will. Assuming people won't do it because they don't do it now (when energy is limited) is unwise.
Don't you think some rich people would like to have their own space habitat where they can change gravity, day-night cycle, and the whole ecosystem at will? It's possible with current technology, just very expansive. It creates new real estate from scratch. With enough energy everybody could have one.
I don't see any point at which people decide "this is enough". Always there will be some people that want more.
BTW I agree it won't be a Dyson sphere, it will probably be a Dyson swarm. Much easier to start, cheaper, and has all the benefits of a sphere.
The counterproblem is: capturing energy from a star is one thing, transporting it to where it can be used a different problem (as we even see today with electric cars)
Or maybe they will just mine bitcoin with it, who knows
How do we see energy transport problem with electric cars? That's only a matter of the right sockets not being available. The power grid is there.
Not to mention battery issues (range, charge time, safety, etc) which are getting better, no doubt about it
It's not only a matter of having the right socket
But it has some advantages as well. Imagine 10 000 000 cars with 50 kWh battry capacity each connected to the grid and letting 10% of their capacity to be used for balancing of the network. If the grid has excess power - charge to 100%. If the grid lacks power - discharge to 90%.
That's 50 GWh of balancing capacity.
It basically solves the problems with unpredictability of most of the renewable power sources.
Because you're thinking about maintaining status quo of early XXI century Earth (and not that, solar panels won't be enough for that), not about future possibilities.
Space travel, for one, is a huge energy sink if you want to do it in reasonable timeframes. A probe to Mars in a year? Sure, usual chemical rockets will do. A passenger ship in 2 weeks? Now we're talking absurd amounts of energy.
If human history teaches us anything, it's that there's always use for more energy. Hell, recently we've been inventing some potentially infinite energy sinks - like the idea of running the economy on cryptocurrencies. I'm still not sure whether Bitcoin is a conspiracy to have humanity cook itself on Earth, or to force humans to start building a Dyson sphere in the next 100 years...
You can throw all the fuel you want at a chemical rocket and it won't take you to Mars in less than a year (more or less).
This applies only if you have to carry chemical fuel with you; you can cheat a lot if you have lots of raw energy available. Chemical rockets won't open up the outer Solar System to us, but beamed power just might. Hell, at the Dyson sphere technology level, you could just push things around the system with giant lasers.
(Yes, that same technology could also be used as a powerful weapon, but it's the unfortunate feature of distances in space - anything interesting you'd like to do in timescales we're used to from daily lives requires handling energy in levels and forms that could be used as weapons of mass destruction.)
Jokes aside, "A truly advanced civilization wouldn't need that much energy" reminds me of "640K ought to be enough for anybody", energy is in some sense like RAM, the more you have, the more you can do with it.
Relatedly: stealth as shown in The Expanse is impossible.
https://www.forbes.com/sites/chadorzel/2015/12/22/the-expans... (the article also tackles Dyson spheres)
(TL;DR: next to impossible)
Any sufficiently advanced technology is indistinguishable from magic.
-- Arthur Clarke
Granted, the apparent "red/brown dwarf" of a Dyson sphere would have much larger size than usual, but on cosmic distances, individual object sizes aren't measured directly - instead we infer them from indirect measures such as light emission and gravitational effects, & comparing to known references & theoretical models.
We can assume some advanced civilizations would want to keep private for safety reasons - as to not invite hostile attention - and thus would do their best to closely approximate spectrum of actual red or brown dwarf through engineering. Meaning we couldn't tell them apart from actual red or brown dwarf without getting close enough to observe the size directly, or somehow recognizing minute deviation from expected spectra.
Right now we may be looking at several advanced (Type II) civilizations, mistakenly dismissing them as mere red dwarfs.
dexen's dictum #2: presume all apparently planet-less cold stars to be potential Dyson spheres until positively proven otherwise.
[1] I've just realized a full Dyson sphere would be a good Faraday cage, preventing radio emissions leaking outside.
Also, on the topic of advanced civilizations being coy:
> "Once there were three tribes. The Optimists, whose patron saints were Drake and Sagan, believed in a universe crawling with gentle intelligence—spiritual brethren vaster and more enlightened than we, a great galactic siblinghood into whose ranks we would someday ascend. Surely, said the Optimists, space travel implies enlightenment, for it requires the control of great destructive energies. Any race which can't rise above its own brutal instincts will wipe itself out long before it learns to bridge the interstellar gulf.
> Across from the Optimists sat the Pessimists, who genuflected before graven images of Saint Fermi and a host of lesser lightweights. The Pessimists envisioned a lonely universe full of dead rocks and prokaryotic slime. The odds are just too low, they insisted. Too many rogues, too much radiation, too much eccentricity in too many orbits. It is a surpassing miracle that even one Earth exists; to hope for many is to abandon reason and embrace religious mania. After all, the universe is fourteen billion years old: if the galaxy were alive with intelligence, wouldn't it be here by now?
> Equidistant to the other two tribes sat the Historians. They didn't have too many thoughts on the probable prevalence of intelligent, spacefaring extraterrestrials— but if there are any, they said, they're not just going to be smart. They're going to be mean.
- Peter Watts, Blindsight
And the corollary to Watts' Law (if he doesn't already have one I call dibs on this being called that) is, of course, that if there are any intelligent, spacefaring extraterrestrials, they're going to be sneaky.
The problem is that where this would be economically viable, you would generally already choose to use solar panels for the electricity -- cheaper and similarly/more efficient.
But then I'm not up to date on the state of play in peltier advances. I've read some fascinating developments in rectenna's, though no efficiency numbers jumping out. But something that could completely change this whole area of electricity generating. Could this design be adapted to any new tech though if something wow around the corner jumps out as being x better than the best peltier. Maybe from what I can tell, but for now it has some niche uses without a doubt, but you won't see them in your neibours back yard or roof anytime soon if ever.
> Another application is radioisotope thermoelectric generators which are used in space probes, ...
Radiative cooling functions both during night and day.
https://news.stanford.edu/2017/09/04/sending-excess-heat-sky...
https://www.technologyreview.com/s/532826/material-cools-bui...
edit - with pan-galactic tickets getting a little bit more expensive every visit.
You could imagine a dystopian sci-fi novel where "at the end of times" the only source of energy available is this - slowly leech heat out of your planet to make some energy. Decisions, decisions...
It's a gloomy scenario, but we wouldn't run out of the energy too quickly:
>Nearly half of the Earth's heat comes from the radioactive decay of materials inside [1]
[1] https://phys.org/news/2011-08-radioactive-key-ingredient-ear...
(Kind of like a heat pump, only that it could completely power itself from the heat in the air instead of needing to consume electricity.)
Maybe we could make double-sided solar panels: One for the daytime, one for the nighttime.
4 microwatts per square meter is pretty useless.
4 watts per square meter is a breakthrough.
64 nanowatts * 1,000,000 = 0.064 watts so I assume some of those numbers are simply wrong.
That 4 watt number comes from a confused paragraph and it is possible the journalist broke some numbers while handling them.
It seems unlikely you could improve the system by 64,000,000 using ambient temperature at night, operating extremely close to a theoretical maximum regularly, and be cheap enough for 4w/m to be useful.
It's sorta like capturing braking energy. This used to be dissipated as heat but now can be turned into energy which improves MPG and therefore reduces the need for fossil fuels, no?