3 ms·
> an improvement by about 33% Yep. It's better than nothing, but we'd need to find orders of magnitude from somewhere. I don't think they're there to be foun
by regularfry 3y ago
> an improvement by about 33%
Yep. It's better than nothing, but we'd need to find orders of magnitude from somewhere. I don't think they're there to be found, personally: keeping big lumps of metal off the ground with aerodynamic lift runs into fundamental physical constraints relatively quickly (you can do the maths on glide slope and gravitational potential energy - just by rough order of magnitude it's mindboggling that it works at all).
And you're right, we do have this problem right now. Anything that wants to keep our travel patterns as they are today needs to confront the reality that its energy requirements make any other consideration a rounding error. From my point of view the big picture is fusion or bust, but that's, uh, a bit of a long shot.
The good news is that air transport emissions are only about 2% of the total, so there are much more productive lower-hanging fruit to tackle.
- credit_guy 3y agoThinking a bit more, there's nothing special about airplanes. The world consumes about 100 million barrels of oil per day. I guess most is transportation, but in the end it does not matter. There are about 7.5 barrels to a ton, so about 13 million tons daily, which is very nearly 5 GT per year. Each ton of oil produces about pi (3.14) tons of CO2 (of course pi is just a coincidence, but it's easy to remember). So about 15 GT of our worldwide 50 GT greenhouse gas emissions come from burning oil. How are we going to replace that? 5 billion tons per year means about 150 tons per second. At about 40 megajoules/kg, that's 6000 GW. Six thousand large (1 GW) power plants. You say it's fusion or bust. What if we had fusion today? Commercial, economical fusion. As easy to build as natural gas power plants. How are we going to build 6000 large such power plants?