for someone who worked in this area, you have an unbelievably short term view.
humanity either has fusion reactors or it doesn't. imagine what we can do with them, the spacecraft we can build, submarine cities, one in every home. Mars, Europa. It's not where we'll be 10 years after we do it, but 100 years, 500 years. To get there, we've got to step forward now.
"What were they used for?" is asked like there's only one answer.
- the author literally goes to lengths to explain that they believe they had multiple purposes at different places/times. It's like you didn't actually read the article...
Understanding why you're doing something at the strategic level, helps you make decisions at the tactical level without having to go back up the chain every time. Without this knowledge, someone else has to make decisions that you are best placed to make.
"is the total amount of oxygen that your muscles can extract from your blood per minute"
genuine question, but wouldn't this also correlate with muscle mass? you can put on a LOT of muscle, so doesn't more muscle mean more oxygen being extracted from your blood?
Is there even an elephant in the room? Most of these other countries have effectively free access to health care, whilst millions of sick American's avoid seeking care because of the crippling debt that comes with it.
Also, I know how unpopular this opinion is, but as someone who's lived in America, several European countries, and Australia... the average American has a lower standard of living than the average European, and the bottom of society in America tends to fall much lower than the bottom in a European city.
Life is more civilized in France, Italy, Spain than in the US. Sorry :D
because light doesn't experience time, and the closer you get to the speed of light, the less time you experience. So what OP didn't say was that, while YOU can travel many lightyears in your lifetime, everyone you know will long be dead.