eli5-how do we know for sure how big space is? and how do we know we are right about everything we know in space?
In: Planetary Science
>and how do we know we are right about anything
That is the neat thing: we don’t
Science is not built to be right, but to be accurate. Physics is *the best available description of measurable phenomena*, it is not expected to be “right”
Of course some things are undoubtedly *not wrong*.
Astrophysics is quite a complex field of study, but we have solid evidence that:
1. light moves at a constant speed
2. the universe expands ever faster
3. at some point in the past, the universe was so small that we can assume it began its existence just then
4. The universe doesn’t have a geometrical center
This information is enough to estimate the size of the observable universe, any light further than that would have needed to be emitted *before* the start of the universe for us to see it.
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