Pg 441 Questions Flashcards
What is meant by the Local Group of Galaxies?
A neighbourhood of galaxies
Give 2 reasons why elliptical galaxies are thought to be older and more evolved than spiral galaxies
-elliptical galaxies rarely form new stars
-elliptical galaxies have little interstellar matter
Explain the difference between a barred spiral galaxy and a spiral galaxy
Barred spirals have well-defined bars running through the middle
How do astronomers think irregular galaxies form?
From the collision of 2 or more galaxies
The arms of a spiral galaxy are thought to have formed as the result of density or pressure waves sweeping the galaxy. When these pressure waves collide with the dust and gas, what will form within the arms?
Stars
Describe how 2 galaxies in collision could produce a supermassive black hole or quasar
-huge amounts of gas are pushed toward the supermassive black holes of the remaining galaxy
-large amounts of energy in the form of radiation are released by the black hole, right before the gas is consumed
Why are hot stars blue and cold ones red?
Hot stars are blue because most energy is emitted in the blue parts of the spectrum
Would life as we know it be able to exist on a planet circling a star in the galactic core?
Life would not be able to exist near a black hole
What type of signal is given off by a quasar?
Radio
What is a galaxy cluster and what keeps it together?
-galaxy clusters are large groupings of galaxies, from hundreds to tens of thousands
-the intense gravitational pull of black holes keeps the cluster together
How many stars does a globular star cluster contain?
Thousands to millions
How many stars does an open star cluster contain?
A few hundred
Age of the stars in a globular cluster
Very old
Age of the stars in an open cluster
Young stars, 10 to 30 million years old
Shape and size of a globular star cluster
Spherically shaped, 10 to 30 light-years across
