Canis Major
0Loading crowd target
0Loading crowd target
7correct to beat the crowd
40 free Canis Major trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Canis Major, the Greater Dog, is one of the easiest constellations to find, because it holds Sirius, the Dog Star, the brightest star in the night sky. People have watched it for thousands of years, and it has left its mark on calendars, myths, flags and even the weather phrases we still use. This quiz covers the Big Dog from nose to tail: the stories the Greeks and other cultures told about it, the constellations around it, the science of Sirius and its hidden companion, and the giant stars, clusters and nebulae inside its borders. Every answer comes with a short explanation, so you pick up a fun fact with each question. It is written for stargazers, students and quiz fans alike. Some questions are easy wins, and a few are for people who know their way around the night sky.
30 of 40 questions with answers and explanations. Play the quiz
Q 01Canis Major and Canis Minor are traditionally drawn as dogs trailing which constellation across the winter sky?
Orion
Orion is the hunter both dogs trail, though the earliest Greek writers gave him only one dog. The smaller second dog had joined the picture by Roman times.
Q 02Sirius, nicknamed the Dog Star, has a faint companion star that astronomers affectionately call by which name?
The Pup
The Pup was first spotted in 1862 by American telescope-maker Alvan Graham Clark, who was testing a new lens when a faint dot appeared beside Sirius.
Q 03The yearly dawn return of Sirius warned ancient farmers that which great river was about to flood?
The Nile
The Nile flood began soon after the star's dawn return each year, so the Egyptians worshipped Sirius as the goddess Sopdet, bringer of the flood.
Q 04Sirius is the brightest star in the night sky, almost twice as bright as which runner-up star?
Canopus
Canopus is in truth far more luminous than Sirius. It only looks fainter because it lies much farther away, while Sirius is one of the Sun's nearest neighbours.
Q 05Which book series features Sirius Black, a wizard named after the Dog Star who can turn into a huge black dog?
Harry Potter
Harry Potter's Black family names its children after stars and constellations, which is why Sirius has cousins called Bellatrix and Andromeda.
Q 06The dog days are named for the dawn return of Sirius, which the ancient Greeks watched for in which season?
Summer
Summer heat was blamed on the star itself: the Greeks feared that its dawn appearance made plants wilt and men weaken.
Q 07Chinese astronomers saw Sirius not as a dog but as which other animal, a sign of invasion and plunder?
A wolf
A wolf prowled the Chinese sky: Sirius was the Celestial Wolf, and a nearby pattern of stars formed a bow and arrow aimed straight at it.
Q 08NGC 2359, a glowing gas bubble in Canis Major blown by a single hot star, is better known by which nickname?
Thor's Helmet
Thor's Helmet spans about 30 light-years, and the star at its centre is thought to be in a brief stage just before it explodes.
Q 09Which country's flag shows Sirius and other Canis Major stars among 27 stars for its states and federal district?
Brazil
Brazil gives Sirius to the state of Mato Grosso, and each star on the flag is sized by how bright the real one looks in the sky.
Q 10Sirius B, the faint companion of Sirius, packs the Sun's mass into a ball roughly the size of which planet?
Earth
Earth is about the right size, yet Sirius B weighs as much as the Sun. It is the collapsed remains of a star that was once about five times the Sun's mass.
Q 11Which bright star has a Greek name meaning before the dog, because it rises shortly ahead of Sirius?
Procyon
Procyon is the brightest star of Canis Minor, the Little Dog. About five light-years from Sirius, it is also that star's closest large neighbour in space.
Q 12Sirius forms the Winter Triangle with the brightest star of Canis Minor and which red supergiant?
Betelgeuse
Betelgeuse lies hundreds of light-years away, dozens of times farther than Sirius, so the three corners of the triangle only look like neighbours.
Q 13Canis Major is often pictured chasing which small neighbouring constellation, whose Latin name means hare?
Lepus
Lepus crouches just west of Canis Major, and although it has been charted since antiquity the hare stands for no particular figure in Greek myth.
Q 21If the hypergiant VY Canis Majoris replaced the Sun, its surface would swallow every planet out to which one?
Jupiter
Jupiter would orbit inside the star, which is so vast that a beam of light would need about six hours to travel once around its surface.
Q 22Sirius looks so bright partly because it is a close neighbour of the Sun; about how far away is it?
8.6 light-years
8.6 light-years is next door in galactic terms, while the other bright stars of Canis Major lie hundreds of light-years away.
Q 23Which German astronomer deduced from a wobble in the motion of Sirius that the star had an unseen companion?
Friedrich Bessel
Q 14In one Greek myth Canis Major is Laelaps, a hound that always caught its prey; which uncatchable animal did it chase?
A fox
A fox fated never to be caught met a dog fated never to miss. In this telling Zeus ended the paradox by turning both to stone and setting them among the stars.
Q 15Canis Major was among 48 constellations listed in the second century by which author of the Almagest?
Ptolemy
Ptolemy's list has lasted: Canis Major is still one of the 88 constellations that astronomers officially recognise.
Q 16Sirius B was once the heavier of the two stars in the Sirius system; what kind of stellar remnant is it now?
White dwarf
White dwarf is the answer, and Sirius B is the nearest one to us. It swelled into a red giant, shed its outer layers and left only its hot, dense core.
Q 17A clump of stars found in Canis Major in 2003 was hailed as the closest small companion of which galaxy?
Milky Way
Milky Way gravity may be tearing the clump of stars apart, though other astronomers argue it was never a separate galaxy, just part of our own galaxy's disc.
Q 18Which space probe, launched to study the four giant planets, should drift past Sirius in roughly 296,000 years?
Voyager 2
Voyager 2 will still miss by a wide margin, coming no closer to Sirius than about four light-years.
Q 19The Egyptians worshipped Sirius as the goddess Sopdet, who was later merged with which far better-known goddess?
Isis
Isis absorbed her almost completely in later centuries, just as Sopdet's husband Sah, the hunter constellation next door, was merged with Osiris.
Q 20Star cluster M41, just south of Sirius, may have been noted around 325 BC by which Greek philosopher?
Aristotle
Aristotle may have beaten its official discoverer by almost 2,000 years: Giovanni Battista Hodierna catalogued the cluster before 1654.
Friedrich Bessel made the call in 1844, and it took another 18 years before a telescope was good enough to show the companion.
Q 24Which English astronomer found that Sirius had moved since ancient star catalogues, showing that stars are not fixed?
Edmond Halley
Edmond Halley compared the sky of his own day with positions recorded in the second century and found that Sirius, Arcturus and Aldebaran had all drifted.
Q 25Mirzam, a bright star of Canis Major, rises just before Sirius; what does its Arabic name mean?
The herald
The herald once outshone its master: Mirzam is thought to have been the brightest star in the whole sky about 4.4 million years ago.
Q 26Adhara, the second-brightest star in Canis Major, is the night sky's brightest source of which kind of light?
Extreme ultraviolet
Extreme ultraviolet light from Adhara is strong enough to shape the thin gas between the stars near the Sun, stripping electrons from its hydrogen.
Q 27Which holy book mentions Sirius by name in a chapter titled The Star, calling God the lord of Sirius?
The Quran
The Quran names the star because some Arab tribes had worshipped Sirius before Islam, and the verse places God above it.
Q 28In Scandinavia, Sirius was traditionally known as the torch of which god of Norse myth?
Loki
Loki gave the star its Scandinavian name, Lokabrenna, which can also be read as the burning done by him.
Q 29Which French writer's tale Micromégas follows a giant from a planet circling Sirius on a visit to our world?
Voltaire
Voltaire made his visitor almost 39 kilometres tall, an outsider through whose eyes he could comment on Western culture.
Q 30The Lockheed Sirius, a monoplane named after the star, was built at the request of which American aviator?
Charles Lindbergh
Charles Lindbergh bought the first one and flew it to the Far East with his wife Anne, who wrote a book about the journey.