Ballpark — October 16, 2026

Distance light travels in a single nanosecond

12 inches

Light is incredibly fast, but not instantaneous.

Pianos in New York City

20,000 pianos

A classic "Fermi problem" estimation.

Miles of blood vessels in the human body

60,000 miles

Mostly made of tiny capillaries.

Gallons of water an average toilet flushes each year

2,920 gallons

Assuming 5 flushes per day per person.

Years a plastic bottle takes to decompose

450 years

PET plastic breaks down into microplastics but never truly disappears.