Hydrogen is great but it's very difficult to deal with. Unfortunately hydrogen it seems is not a panacea. See here for the lowdown.
Storage: Having to compress it to 700bar and store it is a massive challenge and expensive af. The smallest atom in the universe likes to seep through stuff.
Emissions: currently 90+% of hydrogen generated from flossil fuels so dirty hydrogen won't solve the geenhouse gas problem
Clean hydrogen: generated from wind and solar is great but wind and solar is unstable power
Fuel cells: Due to the water byproduct they like to freeze in winter time. They also require platinum and iridium one is rare and the other is even more rare. These are much more rare than lithium. Also they require mining
So in short hydrogen requires mining both for much rarer metals and for natural gas/coal etc, is difficult to store and therefore costs are not going to be optimal and is mostly..currently...dirty hydrogen. There are massive challenges ahead in order to get hydrogen up to scale while keeping the costs down.
He's the Giorgio Tsoukalos of astronomy/astrophysics haha.
"I don't know so it must be aliens"
1) Why did they reveal to the public this thing exists? 2) Why do they trust it's going to not harm our nation or its interests by letting it continue to fly? 3) Why do they let it continue to fly & gather intelligence on our nation? 4) Why are they afraid of a balloon crash-landing? -- These aren't incredibly massive; -- Montana isn't exactly a very populated area; -- We have computers that can calculate trajectory pretty accurately to make sure it's not brought down over a populated area. 5) Why would China float such a conspicuous object over our nation, knowing our technology & capability to spot it?
Seriously, after all the years China has spent successfully infiltrating our government offices and business and stealing our military and intellectual property secrets, what would they stand to gain floating a balloon through our airspace?
1) because the people have cell phones and have been recording it and putting it on twitter and the press picked it up and asked the pentagon about it.
2) Because they have seen them over other us territories in the past. This is nothing new.
3) They could also be using the opportunity to gather intelligence about the make up of the equipment on board and therefore shooting it down would negate that opportunity. Also because shooting it down can harm people on the ground so it would have to be properly coordinated over a non populated area.
4) see 3
5) Because China has been agressively challenging the US for quite a while now and even threatening the US claiming that they own the entirety of the South China Sea which is ridiculous and absurd.
And finally though what would they stand to gain from floating it in our airspace? well simple answer, realtime sigint. (signals intelligence).
If I have seen farther than others, it is because I was standing on the shoulders of giants. -- Isaac Newton