Download Galaxy Notes Presentation

Galaxies and Stars
The universe…
…is space and everything in it.
Galaxies
A
galaxy is a cluster of
stars, gas, and dust that
are held together by
gravity.
 There
are three main
types of galaxies:
Irregular
 Elliptical
 Spiral

Types of Galaxies – Irregular…
 Some
galaxies does
not have regular
shapes
 They contain young
stars, dust, and gas.
Types of Galaxies – Elliptical...
Elliptical
galaxies look like
a ball that has been flattened.
These galaxies contain billions
of stars, but have little gas and
dust between the stars.
Contain only old stars.
Types of Galaxies –Spiral…
Spiral
galaxies consist of a flat,
rotating disk with stars, gas, and
dust and a central concentration
of stars, known as the bulge.
Contains middle aged stars
Types of Galaxies – Barred Spiral…
The arms terminate at the
ends
Looks like Spiral Galaxies
without arms extending out.
Contain old and new stars
A
Milky Way
giant spiral galaxy
including our Sun
 The disk’s diameter is
100,000 light years
 Mass is 1,000 to 2,000
billion times the mass of
the Sun
 The Sun lies a little more
than 30,000 light years
from the center
 Cannot actually count the
number of stars in the
galaxy, can estimate as
roughly 100 billion
Andromeda Galaxy
 The
2
other large galaxy in our cluster
million light years away
 More
luminous than us
 Visible
to the naked eye
What makes up galaxies?
Nebulas – giant clouds of gas and dust
where new stars can form. It is
considered the star nursery.
Stars and star clusters
Black Holes – now believed to be the
center of all spiral and elliptical galaxies
Star Clusters
 Globular
clusters
look like a ball of
stars with 20,000 to
100,000 stars on
average.
 Newly
formed open
clusters have many
bright blue stars
with a few hundred
to a few thousand
stars.
Copy this
chart.
You have
only 10 mins.