I always reflexively roll my eyes at these comments. I'd take living under the rule of frivolous dreamers rather than new age puritans any day.

The intent behind my comment was not clear : I dream about stuff which is not frivolous in my opinion. I'd love to see economical nuclear fusion, 2 liters per 100km cars, advanced cancer understanding, interstellar travel. All these things point towards, I believe, a better future (or at least a future with a bit more hope). A supersonic jet doesn't like (for my very novice eyes) a step in the direction of my dreams, hence my question : is there something in it that I should know.

You can make a supersonic electric jet (particularly with lithium-air batteries), or use fuels synthesized using electricity (i.e. hydrogen). It doesn't necessarily need to be a net emitter of carbon.

ah, I've learned something here. I didn't expect a supersonic plane could fly on electricity; that's quite a feat.

Electricity production is the biggest chunk of greenhouse emissions, accounting for 29% while transportation accounts for 21% [0]. Within transportation, emissions from airplanes only account for 9%. Extrapolating, airplanes are then calculated to be responsible for about 1.89%. On the other hand, emissions from vehicles and trucks emit 17.4%.

Applying Pareto's rule, we're better off focusing our efforts on decreasing emissions on electricity production and vehicles.

[0] https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emis...

why do you assume the research and development of this craft must be confined to carbon based fuels for its entirety?

Perhaps there's military applications of their research, so they might do this to get more funding. And once they get more funding, they can spend it elsewhere (or not).

This. We need farmers, not engineers.

We don't need farmers. We've had too many farmers for the last 100 years. That's still going the way of consolidation and increasing automation. Engineers on the other hand are in high demand.

I think it was a reference to Interstellar

https://www.youtube.com/watch?v=_E792RxIpnU

I saw the movie, but I missed the reference. My comment applies to the guy in the movie. He needs engineers too, not farmers. You don't raise agricultural output with more hands, you raise it with better tech.

That’s a very interesting opinion on hacker news.

It's an uncomplimentary reference to a scene in the film Interstellar.

And odd, isn't it?

1) The whole point of Interstellar is, yeah, if you're facing an existential threat, more farmers isn't going to help you much.

2) Farming is one of the biggest contributors to climate change and perhaps THE largest contributor to humanity's impact on the environment.

We probably need to eliminate most farming and replace it with a synthesized vegan diet (i.e. grown in vats, processed to reintroduce texture, etc) if we really care about protecting the environment.

Can we make the vats out of self replicating carbon structures and then stick them out in sunny, sandy soil?

We can (haha, farming), but it's much less efficient than synthesis (i.e. photovoltaics to produce electrolyzed hydrogen/methane which is then fed to hydrogenotrophic/methanotrophic bacteria that produce protein, starches, fats, etc), especially for protein production.

And it competes with nature for land and resources, especially water. And the need to keep pests at bay also causes big impacts. As does the run-off.

>>> We probably need to eliminate most farming

For a start we could just avoid wasting so much :

https://en.wikipedia.org/wiki/Food_waste#Global_extent

If we're imagining technology advanced enough to vat-grow vegetables (and social controls strong enough to make everyone eat them), we might as well just imagine better runoff control, better land usage, and low-toxicity pest and herbicides.

We already do eat vat-grown stuff. And I'm mostly talking about staples, which make up the vast majority of farmland. For anything mashed or made into flour or oil or powder, there's basically no fundamental difference between it being made in a vat versus a field. Whole, unprocessed vegetables like lettuce, etc? Well, that corresponds to a small fraction of farmland, and it also grows great hydroponically. Don't need to grow that in vats.

>>> it also grows great hydroponically

you must be joking. A lettuce which has grown in some backyards, with time and sun (and a lot of fight against various insects, true) tastes so much better.

But maybe your hydroponics are better than mine.

I'm all for optimizing farming if it's possible but I don't want any compromise on quality (taste, nutrients, whatever).