Will Wheaton's Laser Jackhammer

A while ago on July 13th, Will Wheaton proposed that the jackhammer that was annoying him at the time be replaced with a new system, that would, instead of using a vibrating hammer to break apart the rocks and concrete of the urban jungle, vaporize it with lasers. Mr. Wheaton feels that this would be quieter, which would disturb his work significantly less.

An interesting idea for sure, and it would certainly change urban renewal forever. Unfortunately, it would come with some strange side effects. For one, lasers do not remove the rock so much as heat it to about 1200 degrees, at which time it chemically changes to carbon dioxide and a fine mist of glowing orange chunks of calcium oxide that will instantly ignite everything they touch. Elaborate safety systems will be required to ensure that your construction workers do not routinely set either themselves, or passing pedestrians, on fire. In order to prevent this, a vacuum system will suck the molten rock into sealed containers for later re-use.

The energy use of this system will be somewhat extreme. Just like water, most rocks resist being heated up and cooled down, especially the limestone that a typical city like the kind Mr. Wheaton lives in is made of. A power plant capable of putting out some 50 megawatts, the energy used by an entire block of Mr. Wheaton's city, would be required to keep the lasers firing, the vacuum pulling, and the other safety systems containing the mess. If we just plugged this in, brownouts would be likely, and portable power systems are unlikely to keep up with the load. At least, not without being louder than the original jackhammers were.

Lastly, this system might not be quieter. While the sound would likely be less irritating than the repetitive, machine-gun-esque thumping of a jackhammer, it would almost certainly make a loud whirring noise while in operation. The vacuum pump that pulls the heated rock away makes noise. The power use makes a loud hum. The rock makes sounds as it heats up, and chemically disintegrates, plus if any water hits the rock, it vaporizes with a loud hiss. The noise would be continuous, and almost certainly distracting.

As irritating as the construction is, the jackhammer is unfortunately a better solution for the moment. As one possible improvement though, many jackhammers are gasoline fired, making them unnecessarily loud. Instead, we will replace the gas motor with an electric one, which makes no sound by itself. The jackhammer's only sound is now the metal hammer striking the rock, making a tapping sound as it does so. If we then insulate the office buildings a little better, the sound will become unnoticeable to the people working above.

On Geoengineering

Cartoonist Stephanie McMillian of the strip Code Green has a criticism of the effort that I and others have put into geoengineering the earth:
Well, I highly doubt that I'd see millions for geoengineering, or for that matter, turn a profit at all. As for mastery over the earth, I'd argue that we've had that since we managed to figure out fire. I do agree that reducing emissions in the first place is the most ideal solution, but there's a catch.
Specifically, reducing emissions would require an unprecedented amount of cooperation, which is unlikely to be forthcoming, given what people believe. I live in a region not only riddled with global warming denial, but the belief in abiotic oil -- the belief that oil doesn't come from the fossilized remains of things dead for eons, but instead is generated in the mantle and bubbles up, due to handwave handwave god handwave handwave.
Since these people do not believe that global warming is even happening, they are unwilling to make any changes to their lifestyle, energy use, or anything else, in order to resolve what they regard as a non-issue. I have tried to convince them, but they have largely been unwilling to listen. Psychology studies suggest that they are basically un-convincable as they have made this a tribalist issue, in which they have largely defined themselves as not the kind of person who believes. And as for the facts, the facts be damned. If chemistry and physics shows that this is happening, then by jingo, chemistry and physics must clearly be socialist plots.
Since they can't be convinced, the next step would be to try and organize to defeat them politically, which would also be insanely difficult, as they are a very entrenched interest group with the backing of at least 40% of the electorate. We couldn't force it without effectively having a brutal second American civil war, likely to pull in and destabilize other countries as well.
Video blogger Hank Green once lamented that the copyright solution that Youtube, the company that he must work with on a daily basis, does not use the best possible solution for the conflict between people wanting to upload videos that may contain additional copyrighted work (such as someone else's music in the soundtrack), but instead the most possible solution. Similarly, I think that geoengineering is, at this point, the most possible solution, as I do not require universal cooperation to make it happen. It does not challenge the deniers, who are unlikely to even notice.
However, one thing that emission efficiency that she advocates would give us is that it would enable us to geoengineer less. The more carbon we have to yank out of the atmosphere, the more extreme the measures that we will have to resort to in order to actually make it happen. The more trees you can plant, the less I have to feed the ocean. The more you can reduce your use of gas-burning cars, coal-derived electricity, and cement, the less I have to dim the atmosphere to protect against the most catastrophic effects. The more you can use organically farmed produce instead of factory farmed meat, the fewer artificial trees I will have to plant in the desert.
Ultimately, I'm interested in geoengineering to give us a better world than the one nature gave us. A world that has space for both the cities that help us get what we want and need, and the nature that we admire so much. And with practice, I'd like to use what we learn from doing this to turn Mars from a frozen dried rock into a lush world with many human cities, and Venus from a scorching hellish world into a new paradise. And someday when the sun dies, I'd like us to be able to move out into the universe, carrying with us the gifts of the earth, who will continue to live on in a new world, perhaps one not yet born.

Reactionless EM drive

Recently, a Chinese physicist claimed to have invented something that was previously only science fiction. I'm going to have to explain. Most of our motion is thanks to Newton's 3rd law, which states that for every action, there is an equal but opposite reaction. In other words, to move forward, something else must be pushed backwards. When I walk, or drive, or take a train, my shoes or the vehicle are pushing the earth backward, to push me forward. The earth is pushed back a negligible amount. This is bad news for rocketry, as there is now a tyranny of fuel requirements. In order for the rocket to move, it must eject fuel. The fuel has weight. More weight means less thrust for any particular expenditure of fuel. The rocket must be super powerful to move both itself, and the fuel required to move it, which requires still more fuel (because the additional fuel has mass, causing additional inertia). So science fiction writers proposed the reactionless drive, in which no fuel is ejected. Instead, energy is inputted into the system, and somehow directly transferred into motion. This way any energy, such as solar power, nuclear power, or other systems that don't involve a constant stream of exhaust, could keep the rocket moving. The rocket would be much lighter, and thus easier to launch, maneuver, and power. The EM drive is, if the reporting about it is correct, exactly that reactionless drive. Microwaves are bounced around in a container, imparting their energy in the desired direction of motion. Microwaves have essentially zero mass, and can be produced by electrical activity. Since electricity can be generated by all kinds of systems, any of these systems can power the rocket. The drive as described now is not very efficient. Only 2% of the inputted energy becomes motion, the rest becomes heat, noise, and other wasted energy. This drive could not launch a rocket from the earth's surface, and would only really be useful for a rocket that is already in space. However, we can expect refinement of the device as time goes on. And someday, in the distant future, a spacecraft will launch, unfurl its solar panels, and use a reactionless drive like the EM drive to speed it on its way to a distant star. A laser system in solar orbit is tracking the system and providing a steady steam of power. The craft accelerates, going faster and faster until it is traveling at a large percentage of the speed of light. After years of accelerating, it then reverses the process, slowing down until it arrives at a planet, orbiting the distant star. It then deploys its payload. Perhaps this is a scientific probe, to bring data of this distant world to scientists on earth. Perhaps this is a colony constructor, bringing a human colony to a distant world. Perhaps it is something that I can't even conceive of yet. But whatever it is, it will be glorious.