50 free Sirius trivia questions with answers — science & nature quiz, new questions added Aug 2026.
This Sirius trivia quiz covers the brightest star in the night sky, from its place in Canis Major to the white dwarf that circles it every fifty years. The easy questions are ones any stargazer can answer: the constellation, the nickname, roughly how far away it is, what kind of star its faint companion is and which season's dog days it once announced. The harder end is for astronomy and history readers: what the Greek name means, the Egyptian goddess who was Sirius, why the Nile flood was tied to its rising, the astronomer who predicted the unseen companion in 1844 and the telescope-maker who spotted it in 1862, the year Huggins first measured a star's velocity, why some ancient writers called Sirius red, the Polynesian bird constellation it formed, the year it will become the southern pole star, the Dogon controversy, and the satellite radio company named after it. Every answer was checked against encyclopaedia entries for the star, its constellation and its history before publishing, and the supporting sentence is stored with each question. If you enjoy this one, try our Stars, Constellations and Astronomy quizzes next.
30 of 50 questions with answers and explanations. Play the quiz
Q 01In which constellation is Sirius the brightest star?
Canis Major
Its formal designation is Alpha Canis Majoris.
Q 02What is Sirius's popular nickname?
The Dog Star
Canis Major and Canis Minor are pictured following Orion the hunter across the sky.
Q 03What does the Greek word behind the name Sirius mean?
Glowing or scorching
Its earliest recorded use is in Hesiod's Works and Days in the 7th century BC.
Q 04Which star is the second-brightest in the night sky, roughly half as bright as Sirius?
Canopus
Canopus is a distant supergiant, whereas Sirius owes its brilliance mostly to being close.
Q 05Roughly how far from Earth is the Sirius system?
About 8.6 light-years
It contains two of the eight nearest stars to the Sun.
Q 06What kind of object is Sirius B?
A white dwarf
It is nicknamed the Pup and was once the more massive of the pair.
Q 07How long do Sirius A and B take to orbit each other?
About half a century
Their average separation of about 20 AU is roughly the Sun-Uranus distance.
Q 08Which astronomer deduced in 1844 that Sirius had an unseen companion?
Friedrich Bessel
He read the wobble in the star's path across the sky.
Q 09Who first observed Sirius B, in January 1862, while testing a new telescope lens?
Alvan Graham Clark
The 18.5-inch refractor he was testing was then the largest telescope in the United States.
Q 10For which observatory was the 18.5-inch refractor that revealed Sirius B built?
Dearborn
The sighting was confirmed with smaller telescopes that March.
Q 11Who observed the spectrum of Sirius B in 1915 and showed it was a faint white star?
Walter Sydney Adams
That made it the second white dwarf ever identified, after 40 Eridani B.
Q 12Roughly what is the diameter of Sirius B?
About that of Earth
Packing a solar mass into an Earth-sized ball makes it one of the most massive white dwarfs known.
Q 13Which Egyptian goddess was identified with Sirius?
Sopdet
She was later merged with Isis, while her husband Sah, the constellation Orion, was linked to Osiris.
Q 21Which Pacific archipelago at 17°S sits directly under Sirius's path each day?
Fiji
Polynesian navigators used bright stars as latitude markers.
Q 22In the Polynesian 'Great Bird' constellation Manu, which part did Sirius form?
The body
The bird split the sky into two halves.
Q 23Who discovered in 1717 that Sirius and other 'fixed' stars had moved since antiquity?
Edmond Halley
Sirius had shifted about half a degree, roughly the width of the Moon.
Q 24Sirius was the first star to have its velocity measured, in 1868. Who did it?
Q 14Which annual event did the heliacal rising of Sirius herald in ancient Egypt?
The flooding of the Nile
At Cairo the rising fell on 19 July in the Julian calendar, just before the flood.
Q 15How long was Sirius absent from the Egyptian sky each year, seen as an underworld journey?
70 days
Egyptian mummification traditionally took the same 70 days.
Q 16How long is a Sothic cycle, after which Sirius's rising realigns with the civil calendar?
1,461 Egyptian years
The 365-day civil year drifted a quarter-day a year against the star's rising.
Q 17Which season's 'dog days' did the ancient Greeks tie to the reappearance of Sirius?
Summer
Anyone suffering its effects was said to be star-struck, astrobólētos.
Q 18Which animal did the Romans sacrifice to Robigo at the heliacal setting of Sirius?
A dog
The English phrase dog days is a direct translation of the Latin dies caniculares.
Q 19Which Aegean island's people sacrificed to Sirius and Zeus for cooling breezes?
Ceos
Third-century BC coins from the island show dogs and stars with radiating rays.
Q 20Which season did the rising of Sirius mark for the Māori, who called it Takurua?
Winter
In Hawaii its culmination at the winter solstice was celebrated under the name Ka'ulua, Queen of Heaven.
William Huggins
He got the sign wrong; Sirius is actually approaching the Sun at about 5.5 km/s.
Q 25Which ancient astronomer described Sirius as reddish in his Almagest?
Ptolemy
Chinese records consistently called Sirius white, and the redness is best explained by atmospheric effects near the horizon.
Q 26Which two stars join Sirius to form the seasonal triangle seen on northern cold nights?
Procyon and Betelgeuse
Procyon, at 5.24 light-years from Sirius, is its closest large neighbour.
Q 27North of which latitude can Sirius not be seen at all?
73° N
South of 73° S it never sets, making it circumpolar there.
Q 28Around what year will Sirius become the southern pole star?
66,270 AD
It will come within 1.6 degrees of the south celestial pole.
Q 29Which star will eventually replace Sirius as the brightest in Earth's night sky?
Vega
Sirius is currently drawing nearer and will peak at magnitude -1.68.
Q 30Roughly how much more luminous than the Sun is Sirius A?
About 25 times
It is about twice as massive as the Sun with a surface near 9,940 K.