Q 01/05

What is the Andromeda Galaxy's number in Charles Messier's catalogue?

A) M42

B) M33

C) M31

D) M51

Answer · why

C) M31

Messier logged it in 1764 and wrongly credited a German astronomer with discovering an object visible to the naked eye.

Q 02/05

Roughly how far from Earth is the Andromeda Galaxy?

A) 250,000 light-years

B) 2.5 million light-years

C) 25 million light-years

D) 250 million light-years

Answer · why

B) 2.5 million light-years

Four independent methods, averaged, give about 2.54 million light-years.

Q 03/05

The Andromeda Galaxy is described as which type of galaxy?

A) Elliptical

B) Barred spiral

C) Lenticular

D) Irregular

Answer · why

B) Barred spiral

Visible-light images suggested an ordinary spiral, but infrared surveys revealed a bar, just like the Milky Way's.

Q 04/05

Andromeda is the largest member, by extent, of which galaxy grouping that also includes the Milky Way?

A) The Coma Cluster

B) The Sculptor Group

C) The Virgo Cluster

D) The Local Group

Answer · why

D) The Local Group

The group is dumbbell-shaped, with the Milky Way and its satellites in one lobe and Andromeda and its satellites in the other.

Q 05/05

With an apparent magnitude of about 3.4, how can the Andromeda Galaxy be seen from Earth?

A) Only from the Southern Hemisphere

B) With the naked eye on moonless nights

C) Only in infrared light

D) Only through large telescopes

Answer · why

B) With the naked eye on moonless nights

It can be spotted even from areas with moderate light pollution and is one of the most distant naked-eye objects.