Lesson 4 Flashcards
Is most matter in galaxies visible or invisible
invisible
What is dark matter
it is matter that emits no light at any wavelength
True or false it is hypothesized that more than 90% of the universe’s mass is dark matter
true
tree types of galaxies
spiral elliptical and irregular
What is the center region of a spiral galaxy
the central bulge
In a spiral galaxy where do gas dust exist
in the spiral arms that begin in the central disk
Do elliptical galaxies have an internal structure
no
true or false some elliptical galaxies are shaped like spheres and others like footballs
true
In elliptical galaxies what kind kind of stars are more frequent
old red stars
Elliptical galaxies contain little to no
gas and dust
What do scientists suspect about elliptical galaxies
that they form from the gravitational merging of two or more spiral galaxies
How are irregular galaxies shaped
they are oddly shaped
How do irregular galaxies form
the gravitational pull of neighboring galaxies
What kind of stars do irregular galaxies have a lot of
young stars
What kind of galaxy has areas of intense star formation
irregular
Are groups of galaxies distributed evenly throughout the universe
no
What are groups of galaxies held together by gravity called
clusters
True or false most clusters exist in even larger clusters called super clusters
True
What super cluster is the milky way a part of
Laniakea
What are between super clusters
voids
What are voids
voids are regions of nearly empty space
What is the milky way
a spiral galaxy that contains gas dust and almost 200 billions stars it is a member of the local group which contains 30 galaxies in a cluster
Why can people not see beyond the central bulge to the other side of our galaxy
because earth is located inside the disk of the of the milky way
Where is earth located
in one of the spiral arms of the milky way
