Sorry, found it :
http://stackoverflow.com/quest...

I already used it, but forgot it since.

For that amount of money, you could install photovoltaic panels, solar thermal and a water recuperation system on a significant portion of every roof on the planet.
As a bonus, the USA would become a beloved nation and wouldn't need any fighter jet to defend itself.

Pardon my ignorance, but what does "$@" do?
It's not very googleable.

I tend to agree. But it took me a long time to realize just how much energy is contained in one litre of oil. Before that, I also thought that everything was possible for transport.

The burden of proof is on you.
I showed that typical airplanes would need 500m2 of pv panels per passenger in order to fly, even with a perfect propulsion system and maximum solar irradiance.
You need to describe a functional airplane that somehow needs about 10 or 100 times less pv panels to fly.

there is nothing specifying its shape, size, battery capacity or even propulsion system.

Except laws of thermodynamics, that is.

Let's say that a solar plane is white, and a commercial airplane is black.
I bet that your "functional airplane" is still very much dark gray : you still need a pilot, copilot, food, toilets, a few luggage and minimum space for feet and belly.

it makes it very clear that it's entirely possible to replace our environmentally destructive planes with solar planes.

Once again : Not, it's not possible.
Here's a comment I posted 5 years ago : http://science.slashdot.org/co...
The laws of thermodynamics haven't changed much since.

If you try to access google.com from Germany, it automatically redirects you to google.de.
If you want the "original" Google from abroad, you need to type google.com/ncr.
This link should work the same all over the world :
https://www.google.com/?gws_rd...

that insures greater penetration

That's the right word.

The thing is, they really get bad symptoms from all this anxiety. Call it a self-fulfilling prophecy.
It's like those people in Ukraine that lives relatively close to Chernobyl.
Many think "Shitty life, too much radiation, we have no future". So they all drink, smoke, take weird drugs and live like there's no tomorrow.
The radiation isn't high enough to have any direct impact on their body, but they're doomed to die young nonetheless.

Or a slight variation :
you want to boot your laptop for a presentation in front of a few hundred people.
It's 8:50 in the morning, your presentation is at 9:00.
You get a nice blue screen that tells you "Please wait till 30 updates are installed". Then you get "Please wait till 200000 files are updated".
It often takes more than 30 minutes to do so.

It depends on the mentality.
In Germany, you pay the county dump to take your stuff.
In Italy, just a few hundred kilometers away from Germany, the county dump pays you to take your stuff, because they know that nobody would use it otherwise.

It's hard to reason with homeopathic lovers.
Depending on the dilution, you can prove that not a single molecule of the supposedly active stuff has been sold, ever :
https://en.wikipedia.org/?titl...

Yes, now we begin to agree.
It's true that we could live sustainably, provided we stop using cars and planes for everything, we live in smaller flats, we eat local and seasonal food, and stop buying so much crap.
Even though we could, the real question is if we ever will do so before it's too late.
The heavy smoker could also stop smoking any day in theory. But in practice?

I hope you're right for the demographic curve. I'm not so optimistic. WW2 didn't change much the demographics curve for example. You really need a shitload of famine/war/drought to kill a few billion people.