2. WHAT IS A
GALAXY?
A Galaxy is
basically a large
group of stars,
gas and dust
held together by
gravity. This is
the simplest
definition of a
galaxy.
3. What are the types of galaxies?: Size
So we know what a galaxy is but there are different
types of galaxies. When we look through a telescope
we see odd looking galaxies and normal looking
galaxies but we don’t really know there sizes. A
small galaxy might have minimal of up to a couple
thousand stars. People might think that is a lot but it
is nothing compared to our galaxy and the mega
galaxies. Our galaxy, the Milky Way has some 200
billion stars all together. The biggest galaxies out
there have more than a trillion stars. Now that is
just huge. You can also see how big galaxies are by
their age. Younger galaxies tend to have less stars
than the old giant galaxies.
4. What are the types of galaxies?: Shape
The next galaxy are the Elliptical
galaxies. Elliptical galaxies are
the most giant galaxies out of
the 4 and scientist say they are
formed by 2 other galaxies
colliding with each other to give
it a big size and that odd type of
look:
The last galaxy we will see today
is the irregular galaxy and from
its name you can tell it has no
shape at all. They are the most
uncommon but are famous like
the Cat’s Eye galaxy and the M82
which is both a starburst and
irregular galaxy:
5. What are the types of galaxies?: Shape
There are 4 types of galaxies in
our universe. We start out with
our own galaxy the Milky way.
The Milky Way galaxy is a barred
spiral galaxy which means that it
has the shape of a disk with a
bulge sticking out of it and a bar.
It looks something like this:
The second type of galaxy in our
universe is called a spiral galaxy.
Spiral galaxies are the most
common out of the 4 and they
just look like a spiral shape but
with no bulge in the middle.
6. The Milky Way as you know is our galaxy and home that we
live in. It is home to at least 200 billion stars and is considered
a “giant” type of galaxy. Our galaxy is considered a Spiral Type
of galaxy because of its spiral spinning shape and the big
bulge in the middle. The center of our galaxies (which is
called the Galactic Center), like most galaxies contain more
stars than the outer parts. In the center is the main star
Sagittarius A* which scientists are confident it is a super
massive black hole and just recently found out that there are
super massive black holes in the center of every galaxies.
7. The Milky Way is the only galaxy to be recorded to have a
planet with life, although there are billions of galaxies out
there, earth is the main one. Scientist have found the age
of the Milky Way, since our Sun is about 5 billion year old,
the galaxy is at least 5 billion more years old (So roughly
about 10 billion years old) Our Milky Way is between about
750 billion-1 trillion solar masses and is about 10,000 light
years in diameter. Our galaxy is very unique and we are
lucky to have it. From earth to the solar system, all the way
to the black hole. Our galaxy is changing every day.
8. •"Galaxies." SEDS. N.p., n.d. Web. 27 Jan. 2011.
<http://seds.org/messier/galaxy.html>.
•
"NASA - Our Solar System." NASA - Home. N.p., n.d. Web.
27 Jan. 2011.
<http://www.nasa.gov/topics/solarsystem/index.html>.
•
"The Milky Way Galaxy." SEDS. N.p., n.d. Web. 27 Jan.
2011. <http://seds.org/messier/more/mw.html>.
