If we had an easy source of energy.

[Zelig]

A question for the engineers in our audience, is "energy" synonymous with "propulsion" in space travel?

Yes, barring some minor engineering challenges. Equal/opposite reaction, so you can get arbitrary acceleration in whatever direction you want by hurling a grain of sand in the opposite direction with sufficient energy. (Minor engineering challenge here is to built a sand-grain-hurling catapult that doesn't break at those energies.)

 

[Timsup2nothin]

Yes, barring some minor engineering challenges. Equal/opposite reaction, so you can get arbitrary acceleration in whatever direction you want by hurling a grain of sand in the opposite direction with sufficient energy. (Minor engineering challenge here is to built a sand-grain-hurling catapult that doesn't break at those energies.)

Man. Somebody somewhere is taking a grain of sand to the forehead and they are really screwed.

 

[EgonSpengler]

(Minor engineering challenge here is to built a sand-grain-hurling catapult that doesn't break at those energies.)

I remember seeing a documentary about different teams of engineers working on various aspects of a manned mission to Mars; one of the groups had created a plasma engine, but the plasma ate through and destroyed the steel housing. Maybe a magnetic containment field for a plasma engine is something that could benefit from a compact energy source.

 

[EgonSpengler]

Man. Somebody somewhere is taking a grain of sand to the forehead and they are really screwed.

Isn't that the premise of electromagnetic mass-driver cannons? Take a pebble, accelerate it to N percentage of lightspeed, and the resulting kinetic energy is like hitting something with a nuke.

Oh, hey, that brings to mind another use for limitless energy...


Link to video.

 

[Zelig]

Hell, if we've got limitless free energy we can just abandon the sun's orbit, fly the planet around like a giant spaceship and use our magic energy to keep it heated.

 

[Timsup2nothin]

Hell, if we've got limitless free energy we can just abandon the sun's orbit, fly the planet around like a giant spaceship and use our magic energy to keep it heated.

Well, that would be an engineering problem worthy of attention.

 

[Bootstoots]

Given unlimited energy, we would be able to do all sorts of things that wouldn't otherwise make sense. I don't think mining would generally even be necessary. Any rare element could be extracted from seawater or artificially synthesized in arbitrarily large quantities. Arbitrarily large amounts of fresh water would be available by desalination to coastal areas and could then be pumped inland. Fertilizers, pesticides, and other agrochemicals also become far cheaper, which could end world hunger at the cost of causing environmental damage even faster than they are at present. Obviously other environmental problems like global warming wouldn't occur to anywhere near the same extent.

In short, totally free energy would result in a post-scarcity economy. If there still is a small cost associated with the energy, this becomes less true.

 

[BvBPL]

Mining would be more necessary as increases in energy would result in increases in demand for storage and transmission products requiring cooper, gold, and other metals.

Had fusion been around in 1900, you would have seen no real air pollution / acid rain crisis of the 70s and 80s. Instead, environmental concerns would have hinged on clean water and mining concerns.

 

[Zelig]

Well, that would be an engineering problem worthy of attention.

Actually, using magic heat/lights for the entire earth is quite a lot of work... if we've figured out the propulsion thing already, we may as well just tow the entire sun along with us.

Though the levels of energy involved in accelerating the sun by hurling high-energy grains of sand at it could potentially cause some problems to the sun itself.

 

[Bootstoots]

Mining would be more necessary as increases in energy would result in increases in demand for storage and transmission products requiring cooper, gold, and other metals.

Had fusion been around in 1900, you would have seen no real air pollution / acid rain crisis of the 70s and 80s. Instead, environmental concerns would have hinged on clean water and mining concerns.

There I think it depends on whether the energy is literally free or just very cheap. At very low but nonzero prices, mining should increase for those reasons; at zero cost, anything would be extractible from any source that contained it at nonzero concentration, including seawater.

 

[BvBPL]

In sea water, there is approximately .003 micrograms of copper per liter . There are a billion micrograms in a single metric ton. So it would take three hundred thirty three and a third billion liters of sea water to produce a single metric ton of copper from sea water.

In 2009, worldwide copper consumption was 18.2 million metric tons.

It would take approximately 6x10^18 liters of water to meet the copper need for the world for one year. There are about 1260x10^18 liters of sea water on the Earth.

Sea water ain't a viable source for metals even with unlimited energy.

 

[Mouthwash]

Why is everybody speculating about 'limitless free energy' when that is not even remotely what I'm talking about?

The problem is not that 'there's not enough energy' (there is plenty), but that there is an insatiable demand for energy. Not sustainable, inexhaustible energy, but the quick-fix-immediately-available-but exhaustable energy. We prefer to drive our cars and pollute our world, despite pious words of our leaders to the contrary. No hypothetical will solve that problem, because it's not about need, but about desire.

(Your hypothetical already answers itself, by the way. It solves a real problem by pretending it didn't exist in the first place. That's why I saw no need to comment on it.)

So you are you telling me that a world with cheap nuclear power would wind up being not much different than our own? I'm not literally claiming that we have all the energy we will ever need. Do I need to change the thread title?

EDIT: Done. Not as catchy, but there should be less nonsense.

 

[BvBPL]

Why is everybody speculating about 'limitless free energy' when that is not even remotely what I'm talking about?

Agent327's comment about "enough power" not being a meaningful term explains this. The demand for consumption will always outstrip supply. So when you talk about easy energy people assume that means easy energy for desires, not for needs.

 

[classical_hero]

I believe the world would be exactly the same as it is right now. Remember that most of our oil is used on transport and other things, rather than generation of energy, so we will still need oil to be produced. We will still have need for so many things and perhaps even more things, so I don't see a vastly different world as we have right now.

 

[LamaGT]

A question for the engineers in our audience, is "energy" synonymous with "propulsion" in space travel? I know that one of the issues with getting things into space, and to Mars and elsewhere, is the weight of the fuel needed to get them places.

Fusion would be great for long interplanetary travel, Mars can be reached in something like two weeks with it if not less. It could even allow us to reach Proxima Centauri in decent timeframes (70 years IIRC). The basic idea is that you let the reactor heat up the propellant instead of a chemical reaction, and the resulting effect is much more efficient propulsion.

 

[Valka D'Ur]

They're not all over 10 hours, but top models are pushing 13+ hours and you really have to put some effort into finding anything that does fewer than 7 hours.

I went with the laptop I could afford and which would do most of what I need it to do. I'm not one to cart my computer around, so it's rarely unplugged. I only move it if I'm talking to customer service and need to be talked through something, I need to take it to the repair shop, or the times when I had to vacate the apartment overnight for maintenance reasons.

During a power outage, I get 3 hours. That's it. After that, no computer.

Because "expensive energy" isn't really a problem for star trek replicators and holodecks. I wouldn't expect free energy would help development on either 3d printers or VR headsets/Hololens.

I was being mostly facetious with that comment. I'm actually one of the people who argues that the so-called "everything is free and money doesn't exist in the 24th century" notion is nonsense. That may be how it is in Picard's personal universe, but even Beverly Crusher had to pay for that hideous bolt of cloth she bought at Farpoint.

Hell, if we've got limitless free energy we can just abandon the sun's orbit, fly the planet around like a giant spaceship and use our magic energy to keep it heated.

And who gets to decide where we go? I've always wanted to see Antares (too far north, too much crap in the way of the horizon, and too much light pollution to have a decent view of that part of the night sky), but others might want to go elsewhere.

Actually, using magic heat/lights for the entire earth is quite a lot of work... if we've figured out the propulsion thing already, we may as well just tow the entire sun along with us.

Though the levels of energy involved in accelerating the sun by hurling high-energy grains of sand at it could potentially cause some problems to the sun itself.

And leave the rest of the solar system behind? That would be unethical if there turns out to be life on any of the other planets or their moons.

 

[Perfection]

A question for the engineers in our audience, is "energy" synonymous with "propulsion" in space travel? I know that one of the issues with getting things into space, and to Mars and elsewhere, is the weight of the fuel needed to get them places.

EDIT: I mean, if you simply hurled a nuclear submarine into space, it wouldn't go anywhere, right? Because it's propellers would have nothing to push. It'd still need some kind of rocket propulsion, wouldn't it?

Yes, barring some minor engineering challenges. Equal/opposite reaction, so you can get arbitrary acceleration in whatever direction you want by hurling a grain of sand in the opposite direction with sufficient energy. (Minor engineering challenge here is to built a sand-grain-hurling catapult that doesn't break at those energies.)

Energy does not equal propulsion but the two are related.

In rocket science there are two really important quantities:
[wiki]Delta-V[/wiki] which describes the total amount of velocity change you can cause (relative to the spacecraft)
[wiki]Acceleration[/wiki] which is how much change you can make in a small amount of time.

The Delta-V you achieve by spitting out propellant follows this equation [simplified for small mass of propellant relative to craft]:
Delta-V*(mass of craft)= (exhaust velocity of propellant relative to craft)*(mass of propellant)

The problem is the kenetic energy equation: E=.5mv^2
Notice the v^2. That means if you want to half the mass of propellant and get the same Delta-V you need to double the energy expended to hurl them away.

The problem with nuclear reactors is while they make a lot of energy they don't make much power (power is the rate of energy) compared to rocket fuel (which are basically explosives). A stick of dynamite can release its energy in an instant but a reactor will take years to release its energy (even though it has significantly more)

The combination of low power and tiny amounts of propellant means your acceleration is very low. So things that require high acceleration like getting into orbit and landing will not work.

There is however a benefit, because you can go at for much longer you can achieve very good Delta-V if you're willing to wait for it. This means reactors are good for long distance travel where you can spend months and years building up kenetic energy.

And something like Zeligs sand catapult already exists: [wiki]Ion thruster[/wiki]

 

[Timsup2nothin]

The problem with nuclear reactors is while they make a lot of energy they don't make much power (power is the rate of energy) compared to rocket fuel (which are basically explosives). A stick of dynamite can release its energy in an instant but a reactor will take years to release its energy (even though it has significantly more)

I can make a nuclear reactor release its energy pretty darn fast...but it won't remain a reactor for very long.

 

[Agent327]

If we had an easy source of energy.

I'm not quite sure what 'easy' means here, but actually, we have two: solar power and wind. Easy and inexhaustible. We only need to invest in them. Like all human institutions, however, industry is slow to adapt. And hey, we got oil, right?

 

[CavLancer]

Think what oil meant for people in 1900, the date of the op example. Almost unlimited energy! Try pushing your car 30 or 40 miles, and that's what one gallon of gas does. In 1900 we were still using animal energy primarily. Farming, getting from place to place. Coal was bringing an end to the age of sail so for many it took a week to cross the Atlantic instead of weeks to months depending on the wind. Coal was connecting cities by train already.

To a guy filling the shoes of an year 1900 person looking at 2015, the energy revolution has already occurred in an unfathomable manner.

My daughter wants to see smileys so I will put some.