Ballpark

Puzzle #32 · 21 October 2026

The five questions from that day's Ballpark, each with its answer, the fact behind it and a link to the source. Rather play it first? It is in the archive.

1. How many Earth years does Neptune take to orbit the Sun?

165 Earth years

About 165 Earth years. In 2011 it finished its first full orbit since being discovered in 1846. Source

Image: NASA · Public domain

2. How long is the mid-ocean ridge, the longest mountain range on Earth?

40,389 miles

40,389 miles, with about 90 percent of it under the ocean. It stretches around the globe like the seam of a baseball. Source

Image: Diego Delso, delso.photo · CC BY-SA 4.0, cropped

3. About how many Penny Blacks, the world's first postage stamp (1840), were printed?

68M stamps

Over 68 million, printed from 11 plates. A matching 2d stamp was issued in blue. Source

Image: Royal Mail · Public domain

4. About how many vacuum tubes did ENIAC, the 1940s electronic computer, use?

18,000 vacuum tubes

About 18,000. One burned out roughly every day or two, and finding the dead tube was the hard part. Source

Image: U.S. Army · Public domain

5. How many DNA base pairs are in one copy of the human genome?

3B base pairs

About 3 billion. Genes make up only about 1 percent of the sequence. Source

Image: PublicDomainPictures · CC0