"Hot" is based on a function of time v. rewards that are on the post. High SP users (like @yabapmatt) that upvote on posting can spring onto the "Hot" page because their reward to time ratio is so high.
If the post does not continue to receive upvotes, it will fall down the "Hot" page and disappear off it relatively quickly. If it does receive upvotes, it may linger and then appear on "Trending" as well.
OK, that actually helped a little... thanks!
You're welcome! I'm always happy to help