I've been confused for a very long time of how they measure and get like for example Ωmatter = 0.3 and Ωdark energy to be 0.7. I dunno how they came up with these numbers. Before they knew anything about dark energy why did they think Ω matter was 0.3 and not 0.4 or 0.5. I've been reading textbook and they show these calculation which I don't understand how they calculated critical density. Can anyone explain to me how they got the number but I don't want the explanation in math lol that'll just confuse me more XD and what it means to have critical density. Thanx!!!