What’s the heaviest thing in the universe?

When you think ‘heavy’ things, schoolbags, handbags and shopping bags come to mind. Overheard every day at a shopping centre is: “What’s in here, lead weights?” as bags are handed over to the designated heavy lifter.

Lead is a stable metal that’s often used as weights and sinkers. The reason it’s heavy in terms of mass per unit volume (or think about it as per teaspoon), is because the lead atoms are very close, making it a dense material.