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131 votes
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How to survive the heat death of the universe?

Get out I mean, literally. As in "get out of the universe". The heat death of our universe is by definition not a survivable event. That's the bad news. The good news is that it takes a very, ...
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126 votes

What could be the right powersource for 15 seconds lifespan disposable giant chainsaw?

Giant coiled spring. It would uncoil itself and drive the chain. It would provide loads of power on demand. Storing that kind of energy as a coiled spring is dangerous, but I see that as a positive ...
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113 votes

How to monetize free energy without revealing its existence?

You could use your invention to power computer hardware to "mine" a cryptocurrency like bitcoin. "Proof of work" cryptocurrencies like bitcoin deliberately waste enormous amounts of energy generating ...
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  • 780
99 votes

How to survive the heat death of the universe?

No. By definition the heat death is the state where you could no longer do anything. Any actions you do before it only makes it come sooner. Best strategy: Sit still, do absolutely nothing. (I kinda ...
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86 votes

What would be the ideal power source for a cybernetic eye?

Batteries can be made quite small today, and batteries can be recharged wirelessly by magnetic resonance. So feasibly, the battery could be implanted in the temple near the eye and be recharged by ...
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79 votes

How to survive the heat death of the universe?

Hard physics answer I think the question is fundamentally ill-posed. As long as there are humans alive somewhere, the universe is millions to the power of millions of years away from the "heat death" ...
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79 votes
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Justifying the use of directed energy weapons

Laser beams have straight trajectories in anything other than totally unreasonable gravitational fields (where you won't be using bullets, that for sure). This makes them very easy to aim. Lasers ...
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70 votes
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In a post-fossil fuel economy, what could natural gas pipelines be used for?

They can used for underground power and communication lines, as a replacement for overhead lines. The reason why overhead lines are still prevalent in America is due to the initial cost of ...
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69 votes
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How can Elsa's power fuel my Industrial Revolution?

One option is to use stirling engines. They work just as well on cold as on heat. Or rather, they work on a temperature gradient. One of these toys will work if you place it on a cup of hot water ...
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  • 3,433
69 votes

Consequences of an Earth-size object hitting the Sun?

Fzzt. The sun is big. Source It's not the biggest thing out there by a long shot: ... but in our neighborhood, it's the biggest fish in the pond by far. Heck, the Sun belches bigger than us: (...
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66 votes

How can Elsa's power fuel my Industrial Revolution?

Don't Look for Energy - Go for Infrastructure The problem with freezing powers is that they actively suck energy out of wherever they are used. The movement of the energy itself could be useful, ...
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65 votes
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Would using carbon dioxide as fuel work to reduce the greenhouse effect?

It is technically possible to burn carbon dioxide, but not in a practical way. The reason burning carbon produces energy is that the total potential energy of carbon and oxygen is minimized by the CO2 ...
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58 votes

What are the safety margins for destroying a planet from space?

Well, at best you're depositing in the planet (or the powdered remnants thereof) energy equal to its gravitational binding energy. According to Wikipedia, the one true source of truth, the ...
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58 votes
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What would be the ideal power source for a cybernetic eye?

Although I like the classic cyberpunk concept that states that nanomachines build a small turbine generator in one of your biggest veins (like the inferior vena cava), I understand you want something ...
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  • 2,586
55 votes

What is the best way to use my two portals?

Congratulations! You've solved the energy crisis! Place Portal B some distance above Portal A. Now place a turbine blade in between the two of them. Slowly insert a steady stream of water, stopping ...
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54 votes
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With current technology, what would be the best way to store energy for future generations?

Use the extra power to convert atmospheric CO2 to hydrocarbons and store it underground. This offers the long term storage requirements and ease of handling specified in the question. Various Energy ...
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50 votes

Could a species evolve a special organ that stores pure energy & allows it to control its own magnetic field?

Storing Energy Surprisingly, most creatures already do this! Fats built up on the body contain Chemical potential energy, as does glucose molecules in cells. This definitely isn't storing lightning in ...
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49 votes

How to monetize free energy without revealing its existence?

Seed money So you've got a device which can increase the temperature of water in an arbitrary location far from the actual device. A 10 million pound version of this device is basically a weapon of ...
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  • 26.1k
46 votes

How to monetize free energy without revealing its existence?

Consider looking into what and where power is needed, on demand, and people are willing to pay for it. Take for example Electric Car charging points. If you can install one of these with a payment ...
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  • 1,549
46 votes

Is it possible to have battery technology that can't be duplicated?

First of all, the chemistry, structure and principle of operation of the batteries cannot possibly be secret. Most countries have regulatory authorities which need to approve the use of vehicles on ...
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45 votes
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How to harness Jupiter's gravitational energy?

There's plenty of ways to extract energy from Jupiter's gravity. The problem is how do you do so without lowering your house's orbit? Tidal Flexing? (probably not worth it) When two objects interact ...
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44 votes
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Is a food chain without plants plausible?

If phytoplankton count as "not plants", and you want a non-oceanic environment, then the answer is quite straightforward: just take the phytoplankton out of the ocean. You could have a planetary ...
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43 votes

Can stars that are not powered by nuclear fusion exist?

As another answerer provided, Neutron stars already do this. So, I'm going to alter my answer somewhat to address whether there are other means by which a star-like object may exist, besides the one ...
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  • 10.6k
43 votes

In a post-fossil fuel economy, what could natural gas pipelines be used for?

It is actually a trick question, in a fully renewable energy economy natural gas pipelines will continue to transfer natural gas produced from renewable sources. Natural gas normally comes from ...
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  • 24.1k
43 votes
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What would a life-form be like if it's antimatter-based

Potentially, it would be very similar to life made out of matter. Antimatter is expected to have the same chemistry as normal matter, so any lifeforms would work the same way with the exception that ...
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  • 3,435
43 votes

Is there anything about photons and/or space-time that would allow the detection of an energy-based attack from a distance of ten light seconds?

Since it is hard-scince question - the answer is NO, defending ship can do nothing to detect incoming laser attack from enemy ship it does not see. Argumentation is obvious: speed of light is the ...
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42 votes
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What are the safety margins for destroying a planet from space?

Well, Mark Olson and Samuel provide some very respectable math that winds up with the world destroying shot being taken from about 1 AU or the distance from Earth to sun. Yes, yes; it seems very ...
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  • 273k
41 votes
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Shooting an energy beam into the Sun (from the Earth) in order to destroy it

You simply would not be able to do it with raw energy alone. Using a table that I simply love, consider three lines: $3.9×10^{22}\text{ J }$ estimated energy contained in the world's fossil fuel ...
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40 votes

How would relatively cheap and abundant (but not free or limitless) electrical energy at an up-front cost impact society?

It's not that big a deal I'm not sure how you expect 'relatively cheap and abundant (but not free or limitless) electrical energy' generation to change current society... if the solution you propose ...
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  • 2,727
40 votes

How to survive the heat death of the universe?

Hack the Universe The universe is just a simulation running on a super computer somewhere. Exploit a bug so that you can get more energy/matter.
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