How oddly discomfiting to read about researchers trying to tunnel five miles down towards the centre of the Earth.
Earth, as I understand it, is the planet where we live, and if five miles down is thought a lot, the place can't be that big. I used to travel 11 miles to my nearest grocer.
However, it seems five miles is just part of 1,800 that form Earth's 'mantle'. After the mantle comes the outer core (1,400 miles) then the inner core (800 miles).
It still doesn't sound much but the point is the Earth is right hard. Even with giant drills and a B-amp;Q club card, five miles is tough going.
It's scary to think how little we've explored beneath our feet.
Meanwhile, you should by now have had a Government leaflet with this advice: please remain seated until the researchers return. They won't thank you for walking about while they're down there.