Four hundred trillion terawatts (4E26W) of available power. (Getting it is nontrivial, granted.)
Astronomical amounts of raw material. Literally. There is enough iron in the asteroid belt to plate the entire USA a metre deep in iron, should one have that rather silly impulse. Similarly huge amounts of various other raw materials, some of which are beginning to run short on Earth.
The potential of more living space. You know that old saw about land - they aren't making any more of it? Not true, in a spacegoing society. I've seen calculations that tell me there is enough material to build living space (with generous space allocation) for about a quadrillion people - with the power to run their stuff, and the raw material for the people themselves available as well.
There are more subtle benefits as well - including the physical survival of the human species and the maintenance of civilisation. A Dinosaur Killer hits us now? We're shit out of luck. In 3000AD with a million habitats scattered from Mercury to Neptune? We'd barely even notice. Ditto for anthropogenic disasters; recent news reminds me yet again that, for fifty years now, we have lived in the shadow of Ragnarok.
One more: If a subgroup don't like society, then they can move away. Sink or swim; some varieties of experimental society (or "traditional" ones for that matter) wouldn't do very well maintaining a space habitat. Mentioning examples, with sufficient vehemence, would probably get me banned.
And finally: I've heard it said that one of the many causes of Western society's current ills is the lack of anywhere for young men (mostly, some women also) to go and get themselves killed in the attempt to get rich. To put it another way, the lack of a frontier. Go into space, and the frontier will never run out. Life here on this mudball will get quieter, I think.
]]>"Somewhere for young men to go and get themselves killed in the attempt to get rich" was present in very few societies throughout history, and when it was present, the practice was far less prevalent than mythologized version makes it. Europe in particular, which is most of the "Western society", has not had a frontier in 3,000 years.
By every objective measure, Western society today is quieter than at any previous time in history. Current ills are very mild compared to what they used to be.
OTOH, if you count volunteer military service as "frontier", then we have no lack of it, and it invalidates your last paragraph in post #585.
]]>...except that the British Army's infantry (definitely dangerous if you look at the unit casualty rates in Helmand Province) has been continuously undermanned, by thousands, for the last two or three decades [1]. Perhaps it's the lack of opportunity to make a fortune (e.g. the 1860 punitive expedition to Beijing that sacked the Summer Palace)
[1] The resulting pressure to be "less picky" is also a subject of some debate...
]]>Is it just me, or is landing a probe on Mars significantly more "risky" than other distant missions?
]]>I don't know whether this was done at the time, but it seems to me that the designers of Venus probes would do well to consult a builder of submarines - since the pressure is roughly equivalent to a kilometre of water.
]]>