With worldwide cooperation and infinite money, what awesome spacecraft could we see using modern equipment?

[KAL 9000]

Step 1: Get Von Neumann machines/probes  

Step 2: Demolish Inner Planets (after moving everyone on Earth to temporary Stanford Toruses, O'Neil Cylinders, or Bernal Spheres) and use the resources to build a Ringworld 

Step 3: Move everyone to the Ringworld 

Step 4: Demolish Outer Planets and use the resources to build a Dyson Sphere outside the orbit of the Ringworld 

Step 5: PROFIT!!!

[Bill Phil]

1 hour ago, KAL 9000 said:

Step 1: Get Von Neumann machines/probes  

Step 2: Demolish Inner Planets (after moving everyone on Earth to temporary Stanford Toruses, O'Neil Cylinders, or Bernal Spheres) and use the resources to build a Ringworld 

Step 3: Move everyone to the Ringworld 

Step 4: Demolish Outer Planets and use the resources to build a Dyson Sphere outside the orbit of the Ringworld 

Step 5: PROFIT!!!

One problem. There is no known material that can handle the stress of a ring world... A topopolis would be more practical. 

[StrandedonEarth]

1 hour ago, Bill Phil said:

One problem. There is no known material that can handle the stress of a ring world... A topopolis would be more practical. 

Scrith . It's a known material. Only problem is that it's fictional. But I wonder if a Ringworld rotating at a slower speed (less centrifugal gravity) would fall within known RL material capabilities, and if so, how slow would it need to go (what would the centrifugal gravity) be?

The next problem is attitude jets to keep it centered. Also need meteor defence. 

Edited June 8, 2017 by StrandedonEarth

[ModZero]

On 6/8/2017 at 3:07 PM, KAL 9000 said:

Step 2: Demolish Inner Planets (after moving everyone on Earth to temporary Stanford Toruses, O'Neil Cylinders, or Bernal Spheres) and use the resources to build a Ringworld 

Step 4: Demolish Outer Planets and use the resources to build a Dyson Sphere outside the orbit of the Ringworld 

Pretty sure that would violate planetary protection guidelines. I'm going to propose birth control as a low-tech alternative solution to the living space problem.

[wumpus]

3 hours ago, ModZero said:

Pretty sure that would violate planetary protection guidelines. I'm going to propose birth control as a low-tech alternative solution to the living space problem.

Good luck.  Remember that population levels are the classic example of how exponential grown/decay happens.  Long term, the growth level needs to be zero, but people get rather testy if you make decisions about their reproductive freedoms for them.

Also, if you are moving humanity: why not Trappist-1?  Change a billion year lifespan of your topopolis to a trillion year (I doubt any known material actually lasts that long.   But if you are going that extreme, why not go for the long tick).

[ModZero]

4 hours ago, wumpus said:

Good luck.  Remember that population levels are the classic example of how exponential grown/decay happens.

They are a classic bad example of how exponential growth works. By now we have plenty of examples of how populations react to stimuli in regards to how much children they have. Especially if you give all the useful tools to the part of the population that has to go through one of the most dangerous activities people can go through, just to push a baby out and then be stuck with the rascal for 18 years.

So yeah, birth control is both viable, more realistic, and more sustainable than converting a solar system into a parking lot. Note that even the Culture books don't convert planets to building material - because that's just boring. And "zero in long term" isn't good enough. Imaginary permanent few percents of growth would be a good example of exponential growth, in that we'd rather quickly run out of the energy output of the entire universe full of stars.

So, with infinite money, we could finally figure out the male birth control pill. Now that's a scenario to get excited about. I guess we could send some people to explore the Jovian system, that should work as birth control too 

[wumpus]

4 hours ago, ModZero said:

They are a classic bad example of how exponential growth works. By now we have plenty of examples of how populations react to stimuli in regards to how much children they have. Especially if you give all the useful tools to the part of the population that has to go through one of the most dangerous activities people can go through, just to push a baby out and then be stuck with the rascal for 18 years.

So yeah, birth control is both viable, more realistic, and more sustainable than converting a solar system into a parking lot. Note that even the Culture books don't convert planets to building material - because that's just boring. And "zero in long term" isn't good enough. Imaginary permanent few percents of growth would be a good example of exponential growth, in that we'd rather quickly run out of the energy output of the entire universe full of stars.

So, with infinite money, we could finally figure out the male birth control pill. Now that's a scenario to get excited about. I guess we could send some people to explore the Jovian system, that should work as birth control too 

Now go and check Japan's population.  Individual control of reproduction isn't making an ideal population, is it (Japan being weird as usual, didn't legalize the Pill until 1999.  Presumably other means were used to crash the population).

Another example would be around the neolithic revolution.  Basically the old "hunter gatherer" is a far superior lifestyle for 99% of the population.  Unfortunately, the "good" areas can support enough population until they use them up, and then they have to move on to marginal areas.  And things get worse once people start farming (and defending) the best areas.  For rock-bottom tech, the ideal human population is extremely low.  For high tech, I haven't a clue (you need a pretty big population to allow for the amount of specialization our economy requires).

Zero growth doesn't just mean avoiding overpopulation.  Negative growth is just as bad and can be preferred by couples.

[ModZero]

58 minutes ago, wumpus said:

Now go and check Japan's population.  Individual control of reproduction isn't making an ideal population, is it (Japan being weird as usual, didn't legalize the Pill until 1999.  Presumably other means were used to crash the population).

Congratulations on owning yourself, Japan's population has been declining for ages.

58 minutes ago, wumpus said:

For high tech, I haven't a clue.

Yes, you already mentioned Japan.

58 minutes ago, wumpus said:

Negative growth is just as bad

Only if you're a neocolonialist, but I'd hope we wouldn't have such people in these parts, so surely you aren't.

You can have an economy that collapses when the growth isn't high enough, but frankly, you can also have economy that collapses when people don't buy enough things they don't need or want, I'd blame the particular brand of economy for that.

(edit: I'm having a bit of fun bending the rules, b/c I kinda think that outlawing "political discussion" is a bit on the funny side, especially on a science/tech subforum, but I think it's best if we stop before the mods kick us out of the forest).

Edited June 11, 2017 by ModZero

[wumpus]

14 hours ago, ModZero said:

Congratulations on owning yourself, Japan's population has been declining for ages.

Yes, you already mentioned Japan.

Hint: if the retirees outnumber the workers, it is not a good situation.  Declining population doesn't necessarily mean good.  Although robotic care for the elderly might be interesting.

[NSEP]

I might just make a list

-Space Colonization

-Free space tourism

-Space trade

-Sea Dragon launch vehicle

-Reusabillity becomes useless since everything is pretty much free.

-More boosters!