Transcript Groups of Stars

Groups of Stars
In our Milky Way Galaxy stars can
arrange themselves in:
Globular clusters




A collection of hundreds of
thousands of stars in a
small area
These tend to orbit around
the centers of galaxies
Believed to be very old
stars
Our Milky Way Galaxy has
at least 150 globular
clusters
In our Milky Way Galaxy stars can
arrange themselves in:
Open clusters



A close arrangement of
a small number of stars
Thought to be created at
the same time from the
same nebula
Eventually they move
away from each other
Pleadies Star Cluster
(also known as the ‘seven sisters’)
In our Milky Way Galaxy stars can
arrange themselves in:
Constellations


An arrangement of stars
that form a recognizable
pattern in the sky
Very useful to find other
celestial objects such as
planets, nebula, other
galaxies, etc.
The Big Dipper
Also known as Ursa Major – great bear
Casseopeia
Cygnus – the northern cross
Orion – the hunter
Canis Major – greater dog
Winter Triangle
The three stars of the
winter triangle
•Procyon
•Sirius (canus major)
•Betelgeuse (orion)
Pointer Stars
Pointer Stars from the Big Dipper
Galaxies


Galaxies are huge
formations of
millions of stars
and clouds of dust
(nebula)
They come in
many different
shapes and sizes
Spiral Galaxies
These galaxies have very distinct shapes with spiral arms radiating
from their centers. Our own Milky Way Galaxy is a spiral galaxy.
Barred spiral galaxy
Similar to a spiral galaxy, but with only two distinct arms and an
elongated or ‘barred’ central core of stars.
Elliptical Galaxies
Elliptical galaxies have an ovoid shape and consist mainly of very old stars with
no new star formation processes.
Irregular Galaxies
Large Magellanic Cloud
Small Magellanic Cloud
Both of these irregular galaxies are small satellite galaxies of the Milky Way.
Location of the Andromeda Galaxy
A supermassive black hole at the
center of a galaxy.
Groups of Galaxies
Galaxies tend to form in
groups. Our Milky Way
galaxy is part of the Local
Group of galaxies that
includes the Andromeda
Galaxy and the Large and
Small Magellanic Clouds.
There are 30 known
galaxies in our group of
galaxies. Some galaxy
clusters contain hundreds or
even thousands of galaxies.
Galaxy Collisions
There is lots of evidence
that Galaxies have
‘collided’ with each other
or are on a collision path
with each other. The
collisions can change the
shape of the galaxies and
can also result in the
exchange of materials
between the two galaxies.
Hubble Deep Field View
Looking at a piece of the sky no wider than the width of a dime at 75 feet away
Hubble found about 1500 galaxies which takes the estimated number of
galaxies in the universe into the billions!!