Timeline of the Inevitable

Recently I've been compiling a list of the different ways Humanity will be destroyed assuming we don't develop the technology to escape Earth.
The list is divided into two columns.
The first column contains all the ways in which we could theoretically be destroyed in plausible, but unlikely ways, like for example an alien attack.
The second column lists all the ways in which we will be destroyed inevitably somewhere down the line due to the reality of the laws of Universe we currently exist in.

This is why I'm a hit at parties folks.

Anyways, sometimes the items destroying us will land into both columns, asteroids for instance.
This has given me reason to rework the list (that and the theoretical list is notably larger in size due to late night contributions that really don't belong on there, i.e. Godzilla).

While reworking the list, and looking over literature covering the last five mass extinctions of the dominant species of the past, I was reminded that the Moon exists.
The Moon is solid, unlike the Earth which we all know has a solid inner core surrounded by a liquid outer core.

The thought of the liquid outer core cooling and solidifying enough to meet the mantle hadn't occurred to me, but now that it has, it's on the list.

However, there's a problem.
The complete cooling of the Earth's liquid core wouldn't happen until after the Sun evolved into a Red Giant, which would engulf our planet. With that in mind, does the cooling of the core actually pose a threat?

Keep in mind that these are events that are bound to happen no matter what. They are on the timeline of the inevitable.