I was writing an essay for a school assignment, when I encountered a quote similar the following:
Nobody has encountered a black hole, because they're simply too far away to reach.
I then needed to write a sentence like the following:
"they're simply too far to reach" refers to how black holes are tens of thousands of light-years away at the nearest.
I then wondered if "they're" should be capitalized to say "They're" instead, because it's the first word in that sentence. Should it?