Reddit reviews Seveneves

"The moon blew up without warning and for no apparent reason".

Seveneves

Was in the exact same boat as you; searching for that far (time/space) spanning human epic against certain doom after reading this trilogy. Of all the other similar genre-d books I read afterwards, Seveneves came the closest for me. Give it a shot!

https://www.amazon.com/Seveneves-Novel-Neal-Stephenson/dp/1469246864

You'll love this

Part two of two!

>How can individuals produce fuel from sunlight and waste in their immediate vicinity?
>>They can't.

Moonbuggy! For one so obviously smart you disappoint me! What is photosynthesis? It's the creation of sugar from atmospheric carbon using energy from sunlight. The study of solar fuels is BIG business. There are huge efforts, commercial and academic, to develop a solar fuel methodology. If successful then it will be possible to create solar fuels pretty much anywhere, in the same way that plants can generate fuel wherever they grow.

Here's a starter for ten: http://pubs.acs.org/doi/abs/10.1021/jacs.5b01650

The subject of metabolic engineering and synthetic biology is a subject close to my heart and I am indeed writing a book based in part on my own professional research on the subject. In a nutshell: biology is capable of manufacturing a wide range of materials locally. By harnessing the power of bacteria/algae/fungus to perform chemistry it ought to be possible to manufacture almost any substance anywhere. Light energy is ubiquitous and as long as there is an appropriate feedstock of material (such as sewage, soil or atmosphere) then we can indeed harness biology to perform complex synthesis anywhere on Earth.

Indeed the UK has invested heavily in Synthetic biology, as has the US. https://www.synbio.cam.ac.uk/news/synbio-strategic-plan-2016
https://synbiobeta.com

However, I admit that there are practical difficulties in scaling such technology up to the point where every domestic household is capable of manufacturing a litre of rocket fuel and passing it over to the Spacehenge Committee. But, in principle at least, it may be possible.

As you say, the main cost in the Spacehenge program would be rocket fuel.

> Why would it be carbon free? Whatever materials that are laying around in the immediate vicinity will likely have carbon in them.

I didn't say it would be carbon free! I said it would be carbon neutral. i.e. it absorbs as much CO2 from atmosphere as is eventually released. The principle source of carbon for the growth of plants is atmospheric carbon. So in fact the production of vast quantities of solar fuel could act as a sink for atmospheric carbon dioxide, if the right synthesis pathways could be found.

However, you did force me to learn something here! I looked up the principle components of rocket fuel and it seems that Carbon is not one of the main ingredients! (only in one: polybutadiene) https://en.wikipedia.org/wiki/Rocket_propellant

However, hydrogen is! So I'm envisaging something like the Krebbs cycle where a domestic site benefits from the production of a solar fuel from atmospheric carbon and a waste product of this acts as a feedstock for a rocket fuel production facility. Such an approach would sidestep some safety concerns - some of the compounds used as rocket propellants are quite nasty. However, it may be possible to figure out a synthesis route where solar chemical energy could be stored locally by domestic households and shipped as an inert substance to a local processing facility that produced something like hydrazine or hydrogen peroxide as a by product for rocket fuel, using the domestically produced intermediate as an energy source. Ultimately the energy incident on the households would end up propelling rockets into space.

I stress the word: maybe.

The only requirement here is that some expensive part of the process would have to be performed by local labour across the world as a means for people to contribute to the project. By sinking CO2 from the atmosphere in this process the entire programme could be made carbon neutral, with the carbon itself decoupled from the rocket fuel component. Some highly non-trivial metabolic engineering required to achieve all this.

>That's one of the longest stretches of logic I've ever seen used to find a point to support an argument

Thank you! :D I've been thinking about many of the background ideas for a long time!

>Backing up a highly dubious idea with magical thinking doesn't really help.

Perhaps it seems like magic to one who is less familiar with metabolism and biophysics and the principles of the circular economy as well as how things like nanotechnology, synthetic biology and additive manufacturing are going to combine in the future to form the backbone of our manufacturing capability.

Perhaps the key assumption I have made is that future human economies will be built on the principle of the circular economy in which companies are trading waste so there are zero emissions. Such an economy requires a ubiquitous level of control over chemistry that is on a par with the synthesis capabilities of biology. I merely leveraged the imagined existence of such an infrastructure so as to create a route for every human to contribute a litre of rocket fuel using their spare production capacity. (7 billion litres? is that enough to move an asteroid into orbit??)

>Honestly, your whole comment is you just making things up and then stacking layer upon layer until you have a glorious pile of nonsense.

Hopefully, I have shown that some of the layers in themselves are not entirely nonsense! Their juxtaposition may well be and so I will admit that there may be one or two holes ;P.

I will also admit that the scale of the project is inspired by reading a book called Seveneves by Neal Stephenson https://www.amazon.com/Seveneves-Novel-Neal-Stephenson/dp/1469246864 in which asteroids are used a lot to build orbital platforms visible from Earth.

Really the Spacehenge project is quite simple in its inception.

1. Key idea to capture imagination and act as a focus.
   
2. Discussion about principles that are common to all humans.
   
3. Find a way for people to contribute materially if support emerges for building the sculptures.
   
   
4. and 2) can be conducted without sending a single rocket into space!
   
   
5. the project won't succeed if there isn't a way to achieve mass buy in.
   I have some questions for you:
   
   If an object the size of an asteroid were placed in orbit about the Earth would it be visible? Putting it into a highly inclined polar orbit would be extremely expensive. How much fuel would it take and how big would the asteroid have to be to be visible from Earth at what altitude?
   
   Placing a number of such asteroids in orbit, to mine them, would have tremendous commercial value. The freedom of the low gravity conditions on the asteroids might enable some interesting designs for the mines.
   
   A sculptor takes a large piece of rock and carves an impressive shape into it. Why not take a large piece of rock in orbit and chisel away material such that what is left is pretty to look at and represents some cultural notion that is interesting?
   
   Please also remember that coming up with crazy ideas and seeing where it goes and what other ideas it spawns is a hobby of mine to keep myself amused! It is a form of entertainment as much as anything. www.rubiksplanet.com
   
   What do you think? In Kerbal space program I move asteroids all the time! :D
   

And this: https://www.amazon.com/Seveneves-Novel-Neal-Stephenson/dp/1469246864

One of Stephenson's more readable / approachable books.