708
7 years ago there were no billionaires worth more than $100 billion - today there are 18!
(sh.itjust.works)
Billionaires 7 years ago:
https://web.archive.org/web/20171004002738/https://www.bloomberg.com/billionaires/
Billionaires today:
How is space an adjective in the first one? Shouldn't it be a noun?
These Anglo-Saxons again, putting random spaces into compound words.
I think it's because it's describing the noun.
It's not describing the noun, it's part of the noun.
Quick analogy in German:
space billionaire = Weltraummilliärdär
spacefaring billionaire = weltraumreisender Milliärdär
In German, adjective + noun cannot be written together to form a new noun. To form one, only noun + noun can be used. And English is close enough to Germanic languages for that rule to remain the same, I think.
You are correct. In English, when a noun is used to modify another noun (as an adjective does), it's referred to as a noun adjunct, attributive noun, or, more rarely, an adjectival noun (the last almost exclusively refers to a similar usage in Japanese). While it serves the purpose of an adjective, it's still technically a noun.
Examples are chicken soup, toy store, race car, and boat lane.