49 Fun Facts About Ceres

Ceres orbits in the main asteroid belt, between Jupiter and which other planet?

Mars. Jupiter's gravity is thought to have kept the rubble out there from ever gathering into a full planet, leaving Ceres as the biggest piece.

What was Giuseppe Piazzi compiling at his telescope when he came across Ceres in 1801?

A catalogue of star positions. On New Year's night he logged a faint 'star' that his lists did not show, and over the next few evenings he watched it creep across the sky.

Piazzi found Ceres from an observatory on which island?

Sicily. Piazzi ran the observatory at Palermo, and he named his find after the island's patron goddess.

Piazzi privately suspected Ceres was 'something better', but what did he first report it as?

A comet. It showed no fuzzy halo and its motion was slow and steady, so he suspected a planet, but he wrote that he was careful not to say so in public.

Which 24-year-old mathematician invented a new orbit method to recover Ceres after it was lost in the Sun's glare?

Carl Friedrich Gauss. His predicted position differed from those of other astronomers, yet when Ceres was sighted again it lay close to where he had said.

Ceres seemed to fill the gap predicted by which formula for the spacing of the planets' orbits?

The Titius–Bode law put a missing planet at 2.8 times Earth's distance from the Sun, right where Ceres turned up. A later planet broke the pattern, and it is now seen as a coincidence.

Piazzi's full name for his find, Ceres Ferdinandea, was a tribute to whom?

His king: Ferdinand, Piazzi's monarch and patron. Astronomers in other countries would not use a foreign ruler's name, so the royal half was dropped and only Ceres stuck.

Ceres, the Roman goddess of agriculture, was identified with which Greek goddess?

Demeter. Rome took over her myths wholesale, so Ceres too was said to have been the first to plough and sow and to have taught those skills to humankind.

Which everyday word derives from the goddess Ceres?

Cereal comes from the Latin Cerealis, 'of Ceres'. Chemists borrowed the name as well: two years after the new world was found, a newly discovered element was named cerium in its honour.

What is the old astronomical symbol of Ceres?

A sickle, one of the goddess's emblems. Early asteroids were given symbols of their own until they grew too elaborate to draw, and plain numbers took over.

Which astronomer introduced the word 'asteroid' in 1802 for Ceres and its new neighbour Pallas?

William Herschel. The word means 'star-like': he wrote that even very good telescopes could hardly tell the two newcomers from small stars.

Besides astronomy, what was the lifelong calling of Giuseppe Piazzi, the discoverer of Ceres?

Catholic priest. Piazzi joined the Theatine order as a young man and taught theology in Rome before a mathematics post led him to found an observatory.

What number does Ceres carry in the minor planet numbering system?

1. For half a century Ceres was listed among the planets; only when similar finds piled up did astronomers file it as the first of a numbered series instead.

Ceres was reclassified as a dwarf planet in the same 2006 IAU decision that demoted which body?

Pluto. The vote that demoted it was a promotion for Ceres, which had been filed as an asteroid for generations and now moved up to dwarf planet.

What makes Ceres a dwarf planet?

Its gravity has pulled it round. Smaller asteroids stay lumpy, but Ceres is massive enough to settle into a ball; it falls short of a full planet because it shares its path with thousands of neighbours.

Ceres's diameter is about a quarter that of which familiar world?

The Moon. At about 940 km across Ceres is tiny by planetary standards, yet it alone holds at least a quarter of all the mass in the asteroid belt.

In which TV space drama does detective Joe Miller work the corridors of a colonised Ceres?

The Expanse. Its Ceres is a crowded, colonised port in the asteroid belt, and Miller is the local policeman sent to track down a missing heiress.

Mountains and plains on Ceres are named after what from around the world?

Farming festivals, while its craters take the names of farming gods. The rule extends the theme Piazzi set when he named his discovery after a Roman goddess.

What supplied the Dawn spacecraft's electrical power during its years at Ceres?

Solar panels. Sunlight out there is far weaker than at Earth, so Dawn carried two great wings spanning nearly 20 metres from tip to tip.

A faceless aluminium statue of Ceres has crowned which Chicago skyscraper since 1930?

The Board of Trade Building. The exchange grew up trading the prairie's crops, so its patron went on the roof, and sculptor John Storrs left her without a face.

Which space agency's Dawn spacecraft became the first to orbit Ceres, in 2015?

NASA. Dawn slipped into orbit in March 2015 and stayed for more than three years, swooping at the end to within 35 km of the surface.

Which record does Dawn, the spacecraft sent to Ceres, hold?

First to orbit two extraterrestrial bodies. Carrying one set of instruments to both let scientists compare, like for like, two small worlds that had grown up very differently.

What kind of propulsion carried the Dawn spacecraft on its long journey to Ceres?

Ion thrusters. Each pushed no harder than a sheet of paper resting on your palm, and at full throttle Dawn needed four days to go from 0 to 60 mph.

The brightest of Ceres's famous bright spots sit on the floor of which crater?

Occator. Its patches still gleam because they are young: under two million years old, too recent for the steady rain of meteorite dust to have dulled them.

Once suspected to be ice, Ceres's bright spots are made of what?

Salts left by evaporated brine, mostly sodium carbonate. Dawn traced the brine to a reservoir of salty water about 40 km down, and some may still be seeping up today.

In Roman myth, which daughter of Ceres was carried off to the underworld by its ruler?

Proserpina. Ceres abandoned her duties to search the world for her, and only Jupiter's intervention made the lord of the dead agree to give her up.

What do scientists think Ahuna Mons, the one prominent mountain on Ceres, is?

A cryovolcano. Rather than molten rock it oozed a slushy mix of mud and ice, piling up a lone peak about 5 km high.

What is thought to have erased Ceres's giant craters?

Its sagging icy crust: models predicted 10 to 15 basins over 400 km wide, yet the largest found is about 280 km, and ice-rich ground is thought to flatten slowly until old scars fade.

What did Dawn detect around Ceres's Ernutet crater?

Organic molecules. They are necessary for life though no proof of it, and finds like this are why scientists now rank Ceres among the places worth searching for it.

What did Dawn confirm in 2017 that Ceres has, at least intermittently?

The Herschel Space Observatory had spotted water vapour plumes in 2014.

How did the Dawn mission to Ceres end in 2018?

It ran out of fuel and stays in orbit, silent. The orbit was chosen so the dead craft would not hit Ceres for at least 20 years and contaminate a world that may hold the chemistry of life.

Ceres is counted among the few surviving what from the early Solar System?

Protoplanets: planet embryos that began to grow but never finished. Most were swallowed by the growing planets or smashed to pieces, while Ceres simply stalled.

Like Mercury and Venus, Ceres has no known what?

Moons. Size is no guide: Ida, an asteroid only about 60 km long, turned out to have a tiny one of its own when a spacecraft flew past in 1993.

From which launch site did the Dawn spacecraft set off for the asteroid belt in 2007?

Cape Canaveral. A Delta II rocket threw Dawn clear of Earth, yet over the mission the craft's own engines changed its speed by about as much again.

Ceres is a C-type asteroid, a class named for being rich in which element?

Carbon. Ceres resembles the carbon-bearing meteorites that fall to Earth, but it is no perfect match: Dawn found that its surface holds less iron than they do.

The chemistry of Ceres suggests it may have formed where?

Beyond the orbit of Jupiter, in the cold. Ceres holds ammonia-rich clays, and ammonia only freezes out far from the Sun, so it may have formed out there and drifted inward.

Away from its bright spots, the surface of Ceres reflects about as much light as what?

Fresh asphalt. Ceres bounces back less than a tenth of the sunlight that hits it, which is why its famous spots, reflecting several times as much, look so dazzling beside it.

Ceres's axial tilt of only 4 degrees means what at its poles?

Permanently shadowed craters that trap ice. With the Sun never far above the polar horizon, some crater floors stay dark all year, and Dawn confirmed ice inside at least one of them.

Which planet's discovery in 1781 made astronomers trust the spacing rule that later pointed to Ceres?

Uranus. It turned up almost exactly where the rule placed the next planet out, which sent astronomers hunting for the missing one that the same rule put closer in.

What nickname was given to the 24 astronomers who set out in 1800 to hunt the missing planet?

The Celestial Police. They split the zodiac into 24 beats, one for each member, but Piazzi found Ceres before his invitation to join had even reached him.

After Ceres and Pallas were found, what did astronomer Heinrich Olbers suggest the asteroids were?

Fragments of a shattered planet. The idea sent him hunting for more pieces, and he found one, but it is now thought that no planet ever managed to form there at all.

In Roman myth, Ceres's grief each time her daughter goes back to the underworld brings on what?

Winter. A bargain returns the girl to her mother for part of each year, and for as long as she is below the goddess lets nothing grow.

Which animal did Romans customarily sacrifice to Ceres?

A pig. Ovid tells farmers to spare the ox that pulls the plough and offer 'the lazy sow' instead, and he blames swine for trampling the trail of the goddess's lost daughter.

Which telescope's 1995 images first showed a dark patch on Ceres, nicknamed 'Piazzi' after its discoverer?

The Hubble Space Telescope. Even its sharpest views showed little more than smudges, so what the patch really was stayed a mystery until Dawn arrived twenty years later.

Which asteroid, smaller than Ceres but far more reflective, is the brightest seen from Earth?

Vesta. It orbits closer to the Sun than Ceres does, and its surface throws back more than three times as much of the light that reaches it.

Ceres's temple on Rome's Aventine Hill became the religious and political centre of which class?

The plebeians. The temple was vowed during a famine in the 490s BC, and the commoners' own officials later made it their headquarters.

At Ceres's April festival in Rome, which animals were set loose with burning torches tied to them?

Foxes. Ovid traced the rite to a farm boy who set a thieving vixen alight, only for her to bolt through the fields and burn the standing crops.

In which Shakespeare play does Ceres appear in a masque to bless a young couple's betrothal?

The Tempest. Prospero conjures spirits to play Ceres, Juno and Iris for Miranda and Ferdinand, then breaks off the show when he remembers a plot against his life.

According to Cicero, Ceres was the mother of which two deities?

Liber and Libera. Cicero explained the pair's names from liberi, the Latin for 'children', and Rome housed all three gods in a single temple.