2. What other galaxies are near the Milky Way
galaxy?
“Near” is a relative term when it comes to
galaxies. Within a few million light-years of the
Milky Way are several dozen galaxies that make
up the Local Group. Some of those galaxies,
such as the Sagittarius dwarf galaxy, are
almost in physical contact with the Milky Way’s
outskirts.
3. What is the largest galaxy in the Local
Group?
The Andromeda galaxy, which is slightly
larger than the Milky Way, is the largest galaxy in
the Local Group. Andromeda is also known as
Messier 31, or M31, because it is the thirty-first
object listed in the famous catalog of night-sky
objects compiled by Charles Messier in 1774.
4.
5. When was Andromeda discovered?
According to French astronomer Charles Messier, who
put the great nebula in Andromeda as the thirty-first
object in his famous Messier catalog, the first European
astronomer who discovered Andromeda was Simon
Marius. Marius observed the Andromeda galaxy through a
telescope in 1612; he was probably the first person to do
so. According to non- European records, however, the
ancient Persian astronomer Al-Sufi observed the
Andromeda galaxy as early as 905 C.E. without the aid of a
telescope. Al-Sufi called it the “little cloud.”
6. How similar is the Andromeda galaxy to our
own?
The Andromeda galaxy shares many
characteristics with the Milky Way. It is a large
spiral galaxy, like the Milky Way; it appears to
be roughly the same age as the Milky Way; and it
contains many of the same types of objects
as the Milky Way, including a
supermassive black hole at its center.
Andromeda is somewhat larger than the Milky Way
7. What other galaxies populate the Local
Group of galaxies?
The largest of these Local Group dwarf
galaxies are the Large Magellanic Cloud and
the Small Magellanic Cloud, which orbit the
Milky Way, and Messier 32 and Messier 33,
which orbit Andromeda. Other wellknown
Local Group dwarfs include IC 10, NGC 205,
NGC 6822, and the Sagittarius dwarf galaxy.
The table below lists some of the Local
Group galaxies.
8.
9.
10. What important astronomical event occurred
recently in the Large Magellanic Cloud?
On February 23, 1987, Supernova
1987A appeared in the Large Magellanic
Cloud. It was discovered almost immediately
by two astronomers, Ian Shelton and
Oscar Duhalde, at Las Campañas
Observatory in Chile.
11. What is the Large Magellanic Cloud?
The Large Magellanic Cloud, or LMC, is the
largest dwarf galaxy that orbits our own
Milky Way galaxy. It is an irregular disk galaxy that
is similar in shape to the Milky Way, and we see it
sort of edge on, so it looks like an oblong-shaped
cigar to viewers on Earth. The LMC is about 30,000
light-years across and 170,000 light-years away
from Earth. It is named after the explorer
Ferdinand Magellan, who in 1519 was the first
European to record its existence.
12. What is the Small
Magellanic Cloud?
The Small Magellanic Cloud (SMC), like
its bigger compatriot the Large Magellanic
Cloud (LMC), is a small irregular galaxy
that orbits the Milky Way galaxy. It is a
roughly disk-shaped galaxy about 20,000
light-years across and about 200,000 light-
years away.
13. Located in the Small
Magellanic Cloud,
N81 is a cluster of
about 50 stars within a
mere 10 light-year
distance of one
another. Such unusual
phenomena within both
the Large
and Small Magellanic
Clouds make them
irregular galaxies.
