How do you mean?
It’s just a term to describe not having enough information to know what happened.
It’s “dark” because we can’t see/have no knowledge of what the events were. For history we don’t have written records that describes events during those years. For dark matter we don’t have any information on what it might be.
That’s simply the historical and scientific method of labeling things like that. There is no other deeper meaning to it.
The concept of a “Dark Age” as a historiographical periodization originated in the 1330s with the Italian scholar Petrarch, who regarded the post-Roman centuries as “dark” compared to the “light” of classical antiquity.[1][2] The term employs traditional light-versus-darkness imagery to contrast the era’s supposed darkness (ignorance and error) with earlier and later periods of light (knowledge and understanding).[1] The phrase Dark Age(s) itself derives from the Latin saeculum obscurum, originally applied by Caesar Baronius in 1602 when he referred to a tumultuous period in the 10th and 11th centuries.[3][4] The concept thus came to characterize the entire Middle Ages as a time of intellectual darkness in Europe between the fall of Rome and the Renaissance, and became especially popular during the 18th-century Age of Enlightenment.[1] Others, however, have used the term to denote the relative scarcity of records regarding at least the early part of the Middle Ages.
Source. I use it in the former sense, which I think is more common.
How do you mean?
It’s just a term to describe not having enough information to know what happened.
It’s “dark” because we can’t see/have no knowledge of what the events were. For history we don’t have written records that describes events during those years. For dark matter we don’t have any information on what it might be.
That’s simply the historical and scientific method of labeling things like that. There is no other deeper meaning to it.
Source. I use it in the former sense, which I think is more common.
Laymen may use the former. But historians use the latter:
That’s literally the meaning of the the term, and why it’s also used for ‘dark’ matter.
It doesn’t matter how you decide to use it, what matters is how the scientific community uses it.