No. Lightweight domes as is often shown in artist's illustrations are dumb. Make the domes heavy enough to stay put on the foundation and they double as radiation protection.

Von Neumann machines are fully automated, which is still too hard to do. A seed factory allows some human labor where needed. It just turns the output into self-expansion rather than cars or washing machines like a regular factory.

Also Von Neumann machines make an exact copy of themselves. That's "direct replication". They have to start with a full set of machines needed. Seed factories work like plant seeds. They start with the minimum set of equipment to allow growth, then eventually can make new starter sets. But the new starter sets are not identical to the grown factories.

Social progress is being held back by fear. Rural white people are afraid of losing their position on top of the "natural order of things" (their view, not mine). Having grown up in New York City in an immigrant family, I'm not afraid of people who are different than me. They are just people.

But if everyone is well enough off through productive means, you don't have to be afraid of losing out.

> There isn't enough supply of land

I live on the outskirts of the Atlanta metro area. Beyond where I live, there nothing but undeveloped forest. Developers have been gradually buying up and building, which is how Atlanta has grown. My little town has a "seed and feed" store and a Tractor Supply store. Both of those cater to farmers and large land lots, not 1/4 acre suburban. They would not be here if there weren't the kind of owners they cater to.

> Your plan only works if the person has enough capital

I'm an engineer, so I had enough income to do it. But not everyone does, which is why I mentioned a cooperative approach. People pitch in a little bit each, plus their labor, and fix up or build one house at a time to start with. One of them takes out their share and buys it conventionally. The loan proceeds then return the capital to the group so they can work on the next.

If you get one member like myself who has the spare capital, the other members don't have to contribute anything but labor.

Have you seen my book on Seed Factories? That's the idea of a starter set of machines that are used to make more machines for itself until you have a full range of industry. Using "smart tools" (automation, robotics, software, and AI) it should mostly run itself. A member cooperative can split the cost and make it affordable.

The real magic happens when a mature factory starts spitting out new starter sets. Then it can grow exponentially.

I'm working on the idea of "housing cooperatives" similar to how Habitat for Humanity works. You put in some sweat equity and end up with a house a lot cheaper than developer prices.

I've done property development for myself my whole life. That's either upgrading an existing home, or building from bare land. And I did it as a side gig while having a regular day job.

The stuff I can handle I did myself, and hired contractors for the big heavy jobs. It is not that complicated, you just have to show people how and have a plan. You do need some starter capital, at least enough to buy some bare land and put the utilities in, or for a down payment on a "fixer-upper" that you can then upgrade.

My ideas have been known to make other space systems engineers run away screaming and pulling out their hair :-).

Moving the Earth will eventually be necessary, because the Sun is getting brighter over time. But it is not like, urgent. We have a few hundred million years to figure it out.

She's worth about 3/4 of a billion. She can do whatever she wants at this point. I assume Google paid rent in shares or she got into one of the early funding rounds.

Higher interest rates have knocked the stepladder out from under rising prices. People can't afford the higher priced houses because the monthly payments are too high.

> How do you apply the ∆ V?

Asteroid flybys. If they are massive enough, they cause a shift in a planet's orbit. Then you need to use Jupiter flybys to correct the asteroid for the next pass.

Sea level pressure under a dome on Mars produces a lifting force of 27 tons per square meter. That's the equivalent of 10 meters of solid rock. If your dome is lighter than that, it will be trying to pop off the foundation and has to be either tied or weighted down.

We are, but in the direction of less habitable.

> the "simple" task of terraforming Venus is

To drag several cubic km of metallic asteroids to Venus orbit, heat up chunks with concentrated sunlight, and roll it into thin sheet metal. Then use it as a sunshade to block out the Sun from the whole planet.

On a time scale of 40 years the atmosphere will cool down. It takes so long because not only is the atmosphere much more massive than Earth's, but the surface rock layer just below the gas is also at the same temperature, and has to lose heat too.

The high ground on Venus will preferentially be cooler and lower pressure, so that's where you can start doing stuff.

The combination of a magnetic field and atmosphere protect the Earth's surface from high levels of radiation. The atmosphere does most of the work.

An equivalent mass of anything will do the same job, more or less. Build a habitat dome with 4 meters of glass, and you are protected. This can be multiple panes for practical manufacturing and safety. Or an equivalent amount of dirt piled on the dome with sunlight piped in through side windows.

If you pump up the atmospheric pressure to Earth levels, it will be more than enough. Mars' lower gravity means you need more atmosphere thickness to generate the same pressure.

> artificial methods would take a lot.

Mars is orange because of rust. Turn the rust back to iron, magnetize it, and point all the magnets the same way. No energy required to maintain.

The core of Mars is about 1500 km down from the surface. The mantle density is about 3.5 tons per cubic meter, which at Mars gravity produces a rock pressure of 13 MegaPascals (MPa) per km. Basalt, which is volcanic rock that Mars has lots of, has a maximum compressive strength of 338 MPa. So by the time you get 26 km down, the rock will definitely fail and your drill hole will collapse.

The best steel has about 5 times the strength, but 2.2 times the density. So if you use it to line a drill hole, it will collapse under its own weight at 58 km. You are now 3.9% of the way to the core. The core is out of reach with known technology, so forget doing anything to it.

Jeff's engines are on the launch pad right now. The ULA Vulcan rocket uses two of them in the first stage. New Glenn will use 7 of them and be reusable (eventually).

Vulcan is a standard throw-away rocket intended to replace the Atlas that has flown for many years.

Natural gas started replacing coal due to fracking making it cheaper. This started several years before wind and solar were competitive. Now all three are killing coal, but as wind and solar keep getting cheaper, less of it will be natural gas (14% this year for new NG in the US).

> We'd basically have to build one nuclear power plant a week for the next 25 years.

The world installed an estimated 268 GW of solar in 2022. Assuming a 20% "capacity factor" (actual average output accounting for night and weather) that comes to 53.6 GW average power. Note: US average capacity factor for solar is 24.4%, but not everywhere is so sunny.

A typical size for a new nuclear plant is 1 GW, so that is 53.6 nuclear plants, slightly more than one a week. It is just solar uses a fusion plant that is safely located 149.6 million km away.

We use survey telescopes to look for asteroids. Typically they have been much smaller than the research telescopes. This is about to change with the Rubin Observatory which has an 8 meter mirror, putting into the research size range.

This telescope has a 3200 megapixel camera, and a wide field of view. It will survey the sky frequently, looking for anything that changes (moving asteroids and comets, variable stars, planetary transits, etc.)

More than the half billion dollar Rubin Observatory with its 3200 megapixel camera that will up the discovery of asteroids by a factor of ten?

Climate policies are not what drive change. The profit motive is. Now that renewables are the cheapest energy source, their use is growing exponentially. 2022 was the first year that world-wide investment in renewables matched those in fossil fuels. From here on it will be the dominant place money is going to, and will squeeze out fossil investment.

This is a Mickey Mouse study:

https://www.orlandosentinel.com/business/tourism/os-seaworld-research-disney-20150904-story.html

I was responding to the "taking water from Earth" part of the previous comment. The exhaust from a rocket launch to orbit stays in the atmosphere.

(I've done space systems engineering for 45 years now, so I do understand how rockets work).

ISRU is NASA's obfuscation of "space mining", because it would confuse congresspeople who come from mining states. Actual mining engerineers just call it space mining.

There's plenty of water already in space. Some nearby asteroid types contain up to 20% water and carbon compounds. The carbon compounds typically have hydrogen, and that can be combined with mineral oxides (most rocks) to make more water.

Beyond the "frost line" in the middle of the asteroid belt, water can survive in a low-g vacuum environment, so there is lots and lots of water as water and ice.

Besides, most rocket launches produce more water than they can carry as payload. They take oxygen from the air and burn it with hydrocarbons. The exhaust is CO2 and water.

I haven't run the numbers on basic water, sewer, and electricity needs for residential vs office per square foot, but I would not be surprised if they were different.

In principle you can strip a building down to the bare walls and floors, and redo all the internal systems, but at some point it becomes cheaper to demolish and start over.

There are mixed-use towers in come cities. Trump Tower in Manhattan is an infamous example. Street level +/- 1 or 2 floors is retail, then office space above that, then apartments on top. But it was planned and built that way from the start.