We often read about millions, billions, and trillions with no real idea of the size of those numbers. A guitar is a metre long. A thousand guitars would fit end-to-end along Sydney Harbour Bridge with a bit of room to spare. So far, that’s easy, if a bit odd, to picture.
But when we go beyond millions, the numbers grow incredibly. For each step up, add three noughts to the end of the number.
- A million metres brings you from London to Italy.
- A billion metres takes you around the world 25 times.
- A trillion metres covers more than three round trips to and from the Sun.
If you’re a healthy adult, you might walk at 5km an hour. You would take 12 minutes to walk a thousand metres, and eight days to cover a million metres. To reach a billion metres, you would have to walk non-stop for nearly 23 years. Then things start to get unimaginable.
To walk a trillion metres non-stop, you would have started in the Old Stone Age, about 20,800 BCE. You would have walked non-stop until now, for three-hundred lifetimes of 75 years each. You would be on your two-millionth pair of walking shoes. And you would be pretty tired.
What if we jump to a quadrillion metres? That’s the same as a trillion kilometres. You would have started walking alongside the early apes of the Miocene Epoch in 20.8 million BCE. By now, you would have covered, far more slowly, forty times the distance Voyager 1 has traveled from Earth since 1977.
We’ve now gone from the length of a guitar to one tenth of a light year, which is the distance light travels in a year, moving at 300,000 km per second. Here is how the numbers grow every time you go up a distance.
1 metre
≈ The length of a standard guitar
≈ The width of a standard single bed
1,000 metres
= 1 kilometre
≈ Slightly shorter than Sydney Harbour Bridge
≈ Two and a half laps of a typical running track
≈ 12 minutes nonstop brisk walking at 5 km per hour
100,000 metres
= 100 kilometres
≈ Dublin City Centre to Kilkenny
≈ Tower of London to Ipswich
≈ Times Square to New Haven, Connecticut
≈ 20 hours nonstop brisk walking at 5 km per hour
1 million metres
= 1,000,000 metres
= 1,000 kilometres
≈ Dublin City Centre to Bordeaux, France
≈ Tower of London to Genoa, Italy
≈ Times Square to Columbia, South Carolina
≈ 8.3 days nonstop brisk walking at 5 km per hour
≈ Walking nonstop from yesterday of last week to now
1 billion metres
= 1,000,000,000 metres
= 1 million kilometres
≈ 25 times the circumference of the Earth
≈ 22.8 years nonstop brisk walking at 5 km per hour
≈ Walking nonstop from 2002 to 2025
≈ More than a round trip to and from the Moon
1 trillion metres
= 1,000,000,000,000 metres
= 1 billion kilometres
≈ 2,500 times the circumference of the Earth
≈ 22,800 years nonstop brisk walking at 5 km per hour
≈ Walking nonstop from the Old Stone Age to now
≈ More than three round trips to and from the Sun
1 quadrillion metres
= 1,000,000,000,000,000 metres
= 1 trillion kilometres
≈ 22.8 million years nonstop brisk walking at 5 km per hour
≈ Walking nonstop since the early apes of the Miocene Epoch
≈ Forty times the distance Voyager 1 has travelled since 1977
≈ Just over one tenth of a light-year