Depends where you position your sunlight catching satellite. If you collect energy that would have hit Earth anyway, then the net extra energy that would hit the Earth would be zero. A suitable place to do this is the Lagrange point between the Earth and the Sun (L1), and this would has the dual effect of providing clean energy and blocking sunlight hitting the Earth, reducing global warming in the process! Now all we have to do is to engineer some massive space based mirrors, and launch them 1.5 million km into space...

Granted, the average user is going to fall flat on their face if you show them git's history trees or some Journalist's revisioning software. But give people something simple like time machine with a nice slider, and they might do OK, so long as you do a good enough job of hiding the complexity of what's going on.

If you think solely in terms of undo histories then yes, getting back to a previous state can be time consuming, take up large amounts of memory and/or cause RSI. But If you think in terms of auto-revisioning then a scheme like this could make more sense.

Cat jumps on your keyboard? No problem, switch to an earlier revision

Accidentally delete the doc? No problem

Go back too far? Just spin forward a couple of revision

Admittedly it could be hard for the average user, and it will remember the almost all of the complete historical state of the document (including any insulting things you've written: why would you do that?!), but I'd consider it quite a benefit to be able to roll back time on all docs, not just the ones in a git/svn/hg repository.

Hmmm, maybe a time machine would be handy?

hmmmm, could be tricky, given there are only 1,463,632,361 users (exactly!)

The Lazy guns from 'Against a Dark Backgound' are pretty amusing superweapons, far from his best book though. From the link:'The Lazy Gun is the only weapon known to display a sense of humour.'