# The Bottom Line

In his 2008 book 100 Essential Things You Didn’t Know You Didn’t Know, cosmologist John D. Barrow considers how long a straight line a typical HB pencil could draw before the lead was exhausted.

A soft 2B pencil draws a line about 20 nanometers thick, and the diameter of a carbon atom is 0.14 nanometers, so a pencil line is only about 143 atoms thick. The pencil lead has a radius of about a millimeter, so its area is about π square millimeters. If the pencil is 15 centimeters long, then it contains 150π cubic millimeters of graphite.

Putting this together, if we draw a line 20 nanometers thick and 2 millimeters wide, then the pencil contains enough graphite to continue for the surprising distance L = 150π / 4 × 10-7 millimeters = 1,178 kilometers. “But I haven’t tested this prediction!”

(Thanks, Larry.)

05/21/2022 RELATED: How much of a pencil’s lead is wasted in the sharpening?

(Thanks, Chris.)

# Long Haul

New Zealand’s Whangarei Aerodrome and Morocco’s Tangier Ibn Battouta Airport are on precisely opposite sides of the earth: In an antipodal map projection, which maps each part of the world to its opposite location, the two airports’ runways even cross.

Unfortunately, at 1,097 meters, Whangarei’s longest runway is too short to accommodate a commercial jet with the necessary range, so there’s no way to actually fly from one to the other. For the dedicated air traveler, the next best pairing is Taipei and Asuncion, which are 19,912 kilometers apart.

02/28/2022 UPDATE: Wait, I’m wrong — a reader tells me that on an antipodal projection the closest points on the two runways are about 23.8 kilometers, or 14.8 miles, apart. Still, remarkably close!

# The Queens Giant

The oldest living thing in the New York metropolitan area is this 40-meter tulip poplar in Alley Pond Park in Queens.

With an estimated age of 350 to 450 years, it may already have been growing when Henry Hudson sailed into New York Bay in 1609.

# Wanderlust

A raindrop that falls in Erie County, Pa., will travel 2,147 miles to the Gulf of Mexico rather than 15 miles to Lake Erie.

Via MapPorn. River Runner will trace any drop falling in the contiguous United States.

# “The Slash”

In areas of mountainous terrain and wildnerness, the border between the United States and Canada is kept clear of brush and vegetation to a width of 6 meters, forming a visible line between the nations that’s visible in satellite images.

The deforested segments total more than 2,000 kilometers.

# Misc

• “Worry often gives a small thing a big shadow.” — Swedish proverb
• Uranus was discovered before Antarctica.
• PROTECTORATE is a palindrome in Morse code.
• PUBLIC RELATIONS is an anagram of CRAP BUILT ON LIES.
• If you copy this sentence, be sure to omit “”.

(The fourth is due to Mick Tully, the fifth to David Armstrong.)

# Ambiance

This cottage, at 112 Mercer Street in Princeton, New Jersey, has been home to three Nobel winners: Albert Einstein lived there from 1935 to 1955; physicist Frank Wilczek between 1989 and 2001; and economist Eric Maskin until 2012.

It resides on the National Register of Historic Places and has been designated a U.S. National Historic Landmark, but it bears no outward marker of its significance.

# Express

This is just pleasing somehow: The Japanese railway station with the shortest name is Tsu Station in Mie Prefecture.

The name is written with a single stroke.

# Misc

• POSSESSIONLESSNESSES has nine Ss.
• Trains are older than bicycles.
• 87 percent of the human population lives in the Northern Hemisphere.
• This sentence no verb.
• “God pity a one-dream man.” — Robert H. Goddard

Roald Dahl wrote the film adaptations for two of Ian Fleming’s novels, You Only Live Twice and Chitty-Chitty-Bang-Bang.

(Thanks, Ben and Fred.)

# The Coinage Shield

The “tails” sides of British coins less than £1 can be arranged to depict the Royal Shield from the monarch’s coat of arms.

The full Royal Shield appears on the £1 coin.