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Grinz. I'm more focused on current species problems. Parenting that no longer works, economies that no longer makes sense, politics that is no longer relevant. :-) I'm thinking about ∆V at the sociological level and flat out moving to post scarcity today and finish in 40 years.

Have you ever tried playing Kerbal space program? If you get into it you'll very rapidly understand why SSTO designs are not worth it.

Every kilogram of mass you have to lift to orbit requires multiple kilograms of fuel. And that extra fuel itself requires fuel to lift it. Staging allows you to jettison mass part way, meaning you need to carry significantly less fuel over all.

First stage reuse is a solved problem, and there's multiple very cool ideas for second stage reuse in development right now. We're so close to cracking this.

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.

I agree completely. I'm sure you are awesome. That terrible woman set the bar so low for anyone with your name. Don't change a thing.

There are lots of people going back to the drawing board every day, but so far none of them have found a better model than Lambda-CDM. Certainly not for lack of trying, though.

Fascinating:

The concentration of mass is so great that the fabric of spacetime is warped by gravity, creating an effect that makes the region of special interest to astronomers: a natural, super-magnifying glass called a “gravitational lens” that they can use to see very distant sources of light beyond the cluster that would otherwise be undetectable, even to Webb.

You want to play celestial billiards by using bigger and bigger fly-by. You want to use 200 big asteroids to perturb Mercury the right direction?. Welp, you don't think small. I'm assuming you need a world government to pull this off?

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Babe wake up new James Webb deep field just dropped

It is. It is a recreation of the Milky Way. Some tiny percent has even been explored by players. https://www.elitedangerous.com/

And now if you haven't read "nightfall" by Isaac Asimov you should go do that. Very short story and you won't regret it.

The Nancy regan telescope will suck in more light than any other before it

> 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.

Yes, I imagine such a civ would just scoop up hydrogen from the Sun and run something like an artificial CNO cycle in reactors with that fuel. It makes more sense than using a dyson swarm.

What I meant there is that you can out-power the Sun's output easily even without that, by using the fuel on outer gas giants too. So technically you do not need to do anything with the Sun in order to "reach Type II" (it's defined by power generation, regardless of source).

99.86% of the solar systems mass is in the sun. Over 70% of that is hydrogen that could be used for fuel.

I can't imagine a Type II civilization ignoring such a massive resource. Even if they simply end up "mining" the sun for hydrogen that they use for fusion reactors elsewhere. If they are not taking full advantage of their star, I don't think they can even be considered a fully-fledged Type II

> 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.

Our children children children would be luckier if they can get there. Hopefully.

Wow!! This is amazing. We are so lucky to live in these times!