50 Fun Facts About Blue

Which optical effect, named for a British physicist, makes the daytime sky and the deep sea look blue?

Scattering rises with the fourth power of frequency, so short blue wavelengths scatter far more than red.

Blue light has a dominant wavelength between roughly 450 and how many nanometres?

Shorter blues drift towards violet, longer ones towards cyan.

What was the first artificial pigment, produced in Egypt in the third millennium BC?

The Romans used it too; it turns up in the frescoes of Pompeii.

Which two international organisations chose blue for their flags because of its association with harmony?

In languages, blue is usually the last basic colour term to be named, long after black, white and red.

Ultramarine, the most expensive Renaissance pigment, was ground from which stone?

It was reserved for the robes of the Virgin Mary and at times valued as highly as gold.

The name 'ultramarine' comes from a Latin phrase meaning what?

The lapis came from the Sar-i Sang mines of Badakhshan, worked since the 7th millennium BC.

Which pharaoh's funeral mask is inlaid with the blue stone from which ultramarine was later made?

By the end of the Middle Ages Europe was importing the stone to grind into ultramarine.

Prussian blue, the first modern synthetic pigment, is the traditional 'blue' in what?

Hokusai used it for his wave prints after it reached Japan through Nagasaki in the 1820s.

Which artist's Blue Period, from 1901 to 1904, followed the suicide of his friend Carles Casagemas?

He painted beggars, prostitutes and drunks in near-monochrome blues before warming into the Rose Period.

Blue eyes have no blue pigment; what light phenomenon in the iris stroma gives them their colour?

Mammals are born with blue eyes and any darkening develops afterwards.

The blue whale is the largest animal ever known; roughly how much can one weigh?

A stranded North Atlantic blue whale's heart weighed 180 kg, the largest known in any animal.

A blue whale's diet consists almost entirely of what?

An average whale needs about 1,120 kg of krill a day.

To how low can a blue whale's heart rate fall on a deep dive?

On surfacing it climbs to about 37, near its maximum.

The blue-ringed octopus carries enough venom to kill over 20 adult humans, using which toxin?

There is no antivenom, and the animal is only 12 to 20 cm long.

About half of all breeding pairs of blue-footed boobies nest on which islands?

The blue feet come from diet and are shown off in a high-stepping mating dance.

The blue jay is a member of which bird group?

Like other corvids it hides acorns to eat later.

Under the popular definition, when is a full moon called 'blue'?

Pruett had misread a 1937 Maine Farmers' Almanac article; his version happens seven times every 19 years.

How often does a calendrical blue moon occur?

A genuinely blue-looking moon needs smoke or volcanic ash in the air, hence 'once in a blue moon'.

Bluetooth technology is named after a 10th-century king of which country?

He introduced Christianity to Denmark; the logo merges the runes for his initials H and B.

Which Intel engineer proposed the name Bluetooth in 1997 after reading about the Viking king?

It was meant as a codename but spread through the industry before it could be changed.

The wireless standard's logo binds the runes Hagall and Bjarkan, initials of which Viking king?

The runes come from the Younger Futhark alphabet.

Blue jeans as we know them date from a patent granted to Jacob Davis and Levi Strauss in which year?

The innovation was copper rivets at the pocket corners.

Roughly how much indigo dye, almost all of it synthetic, was produced a year as of 2023?

The natural dye came from Indigofera plants, once common worldwide; synthetic indigo has replaced it almost entirely.

By legend, Roquefort was discovered when a shepherd left his lunch in a cave to chase what?

He came back months later to find Penicillium roqueforti had done its work.

The 'blue chip' stock term comes from which game, where blue chips are traditionally worth most?

Dow Jones lore credits early employee Oliver Gingold with coining it in the 1920s.

The term 'blue collar' was first used for trades jobs in 1924 in a newspaper in which US state?

'Blue laws', by contrast, restrict business on Sundays for religious reasons.

London's blue plaque scheme, the first of its kind in the world, was launched in which year?

English Heritage has run it since 1986.

Blue Peter, on air since 1958, holds what world record?

Its most replayed moment is Lulu the baby elephant relieving herself on the studio floor in 1969.

New Order's 'Blue Monday' holds what sales record?

Peter Saville's die-cut sleeve was designed to look like a 5¼-inch floppy disk.

Which Italian group had a worldwide hit in 1999 with 'Blue (Da Ba Dee)'?

It topped the charts in at least 18 countries and entered the UK top 40 on import sales alone.

Blue Note Records was founded in 1939 by two German-Jewish emigrants, Alfred Lion and whom?

Reid Miles's cover designs and Francis Wolff's photos made its 1950s and 60s sleeves iconic.

Which 1959 Miles Davis album is often called the greatest jazz record ever made?

The sextet included John Coltrane, Cannonball Adderley and Bill Evans.

In which city was Blue Man Group founded in 1987?

A Blue Man must be between five-foot-ten and six-foot-one and able to 'wordlessly emote'.

Which technology company is nicknamed 'Big Blue'?

It began in 1911 as the Computing-Tabulating-Recording Company.

Starting with which Microsoft operating system release did the 'blue screen of death' turn black?

Officially it is a 'stop error'.

Which Blue Öyster Cult song is a classic-rock staple famous for its cowbell?

The band formed in Stony Brook, Long Island, in 1967.

The Blue Nile rises from which body of water in Ethiopia?

In the rainy season it supplies about 85 percent of the Nile's water.

The US Navy's Blue Angels, formed in 1946, are the second-oldest formal aerobatic team after which?

The French team dates from 1931.

Iceland's Blue Lagoon gets its milky blue colour from a high content of what?

It is fed by water from the Svartsengi geothermal power station.

Which Roman emperor used Capri's Blue Grotto as his private swimming hole?

Swimming there is forbidden today; the colour Capri is named after its water.

Blue Ivy Carter charted on Billboard at two days old via which Jay-Z song?

Time called her 'the most famous baby in the world' two days after she was born.

Blue Origin, founded in 2000 by Jeff Bezos, is headquartered in which state?

Its suborbital rocket New Shepard flew Bezos himself in 2021.

Which national football team is nicknamed Les Bleus?

Most national sides wear their flag colours, which is why Argentina, Italy and Uruguay also turn out in blue shirts.

For what invention did Nakamura, Amano and Akasaki share the 2014 Nobel Prize in Physics?

Shuji Nakamura demonstrated high-brightness blue LEDs at Nichia in 1993, completing the set needed for white LED lighting.

Isaac Newton named seven spectrum colours, including blue, to match the number of what?

He believed the musical scale and the optical spectrum were related, and counted indigo separately though today it would just be called blue.

Which German company synthesised indigo in 1878, wiping out vast natural indigo farms?

Under chemist Adolf von Baeyer, the firm's product rapidly replaced the plant dye and became the blue of blue jeans.

Fine blue-and-white porcelain manufacture began in the 14th century in which Chinese city?

The cobalt blue was imported from Persia, and the style was later copied by Dutch craftsmen in Delft and English potters in Staffordshire.

Which Regency dandy created the ancestor of the modern blue business suit?

Brummell set fashion at the London Court in the early 19th century, the same era that produced riveted blue denim work clothes.

Which abbot filled a rebuilt Paris basilica with cobalt-blue stained glass in the 1130s?

He believed light was the visible manifestation of the Holy Spirit; the resulting hue became known as bleu de Saint-Denis and inspired Chartres.

Which French chemist created a synthetic cobalt blue pigment in 1799?

It became immensely popular with painters, decades before Guimet's artificial ultramarine won a French prize in 1826.