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

2.5 million light-years. That means the glow you can see tonight left Andromeda about 2.5 million years ago, long before our own species existed.

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

Barred spiral. Dust hid the bar in ordinary photographs, so it took near-infrared surveys in the 2000s, which see through the dust, to pick out the bo...

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 Local Group. Mutual gravity holds its galaxies together, which is why Andromeda is falling toward the Milky Way while far-off galaxies rush away f...

Q 05/05

At a minimum, how can the Andromeda Galaxy be seen from Earth?

A) With a large observatory telescope

B) With the naked eye on moonless nights

C) With a backyard telescope

D) With binoculars on moonless nights

Answer · why

B) With the naked eye on moonless nights

With the naked eye on moonless nights, no instrument is needed, which is why skywatchers had put it on star charts centuries before the telescope was ...