Lesson 5 Introduction
Completion requirements
Milky Way Galaxy
When you look at the night sky, what you see mostly are stars, stars, and more stars. These stars are part of huge groupings held together by gravity called galaxies.
There are three types of galaxies: elliptical, irregular, and spiral.
In elliptical and irregular galaxies, stars have generally chaotic paths which make it difficult for planets to have stable orbits.
There are three types of galaxies: elliptical, irregular, and spiral.
In elliptical and irregular galaxies, stars have generally chaotic paths which make it difficult for planets to have stable orbits.
Pixabay
Elliptical galaxies have older stars and less dust. Irregular galaxies have younger stars, but more dust, and an increased possibility of collisions between planets.
Our galaxy is of the third type, a spiral. The Milky Way is a flattened spiral galaxy with a spherical bulge at its centre.
From our view on Earth, the Milky Way Galaxy looks like a huge hazy band of stars.
Our galaxy is of the third type, a spiral. The Milky Way is a flattened spiral galaxy with a spherical bulge at its centre.
From our view on Earth, the Milky Way Galaxy looks like a huge hazy band of stars.
Pixabay
Pixabay -Milky Way galaxy from Earth
We live on an outer “arm” of the galaxy. This small arm is between the larger Sagittarius and Perseus arms of the galaxy.
This is a good place to live because we are not in a dangerous location. The centre of the Milky Way has a black hole which could explode our Sun and give off deadly radiation. The outer edges of the Milky Way have fewer elements (magnesium iron, silicon, and oxygen) to support life.
The Milky Way Galaxy is in a small cluster of more than 54 galaxies called the Local Group. Each one of these galaxies contains millions or billions of stars.
Our spiral galaxy is one of millions of galaxies in our Universe. The vast space around us that consists of the solar system and other galaxies is called the Universe.
Read “The Universe” article to learn more. Note, this website requires flash.
This is a good place to live because we are not in a dangerous location. The centre of the Milky Way has a black hole which could explode our Sun and give off deadly radiation. The outer edges of the Milky Way have fewer elements (magnesium iron, silicon, and oxygen) to support life.
The Milky Way Galaxy is in a small cluster of more than 54 galaxies called the Local Group. Each one of these galaxies contains millions or billions of stars.
Our spiral galaxy is one of millions of galaxies in our Universe. The vast space around us that consists of the solar system and other galaxies is called the Universe.
Read “The Universe” article to learn more. Note, this website requires flash.
Pixabay- We live on the Orion Arm of the Milky Way galaxy
Just think—if there are thousands upon millions of stars, how small is Earth in the universe?
The universe is big. Really big. How big? We do not know, except the Earth can be compared to a grain of sand in the Sahara desert.
We cannot comprehend the size of the universe, but we can understand how to measure the distance to the stars.