Flight Through the Universe

We live in the Milky Way galaxy, a swarm of a hundred billion stars. Beyond our galaxy are hundreds of billions of other galaxies. Using a special instrument on the Anglo-Australian telescope astronomers have measured the positions of hundreds of thousands of them. The project is called the 2DF survey. It covers two huge slices of space, each going out four billion light years. By mapping these enormous volumes astronomers can see how galaxies are distributed on a very large scale.

Here we are seeing galaxies at their real positions in space. The survey has netted so many galaxies that astronomers can make an accurate census of them, working out the number of each different type.

Our own galaxy is like this one. A central bulge of stars surrounded by a thin disk.

This galaxy is just a giant ball of stars.

Some galaxies are clustered in groups.

There are vast empty regions with now galaxies at all. The 2DF survey is answering some of astronomy’s most fundamental questions. By knowing where the galaxies are today, astronomers are getting a better understanding of how the universe evolved.

Canadian Heritage Information Network

© Canadian Heritage Information Network 2003


Woodcut

This woodcut shows the astronomer's quest to look beyond Earth's horizons and discover a deeper.

Anonymous
From L'Atmosphere Météorologie Populaire
1888
Paris, FRANCE
© Camille Flammarion


"We live on a tiny blue planet, one of nine worlds that orbit an average-size star called the Sun. Our Sun and its family of planets exist within a vast group of stars called a galaxy.

Our galaxy is called the Milky Way, and it contains nearly 200 billion stars-that’s about the same number as there are grains of sand on a beach.

That might sound like a lot, but it’s only the beginning. The Milky Way is one of about 50 galaxies that form a loose cluster called the Local Group. Some of our neighbours in the Local Group are the Large and Small Magellanic Clouds, the Andromeda galaxy and the Triangulum galaxy.

The Local Group belongs to a cluster of more than 2 500 galaxies, known as the Virgo Cluster. Altogether, these galaxies and galaxy groups form the Local Supercluster. And things still get bigger!

The word astronomy comes from two Greek words: "astron," which means "star," and "nemein," which means "to name."
"We live on a tiny blue planet, one of nine worlds that orbit an average-size star called the Sun. Our Sun and its family of planets exist within a vast group of stars called a galaxy.

Our galaxy is called the Milky Way, and it contains nearly 200 billion stars-that’s about the same number as there are grains of sand on a beach.

That might sound like a lot, but it’s only the beginning. The Milky Way is one of about 50 galaxies that form a loose cluster called the Local Group. Some of our neighbours in the Local Group are the Large and Small Magellanic Clouds, the Andromeda galaxy and the Triangulum galaxy.

The Local Group belongs to a cluster of more than 2 500 galaxies, known as the Virgo Cluster. Altogether, these galaxies and galaxy groups form the Local Supercluster. And things still get bigger!

The word astronomy comes from two Greek words: "astron," which means "star," and "nemein," which means "to name."

© Canadian Heritage Information Network, 2003

Andromeda Galaxy

The Andromeda galaxy-the largest member of the Local Group of galaxies-is about 2.25 million light-years away.

Chris Cook

Chris Cook © 2002


As far as astronomers can tell, the universe contains about 100 billion galaxies. These galaxies are grouped into clusters, which in turn are grouped into even bigger groups called superclusters.

Superclusters are arranged in long filaments that reach through space. These filaments are like tendrils of light that embrace large bubbles of empty space called galactic voids. It’s as if the universe were a vast, frothy sea, with galaxies forming the surface of the bubbles.
As far as astronomers can tell, the universe contains about 100 billion galaxies. These galaxies are grouped into clusters, which in turn are grouped into even bigger groups called superclusters.

Superclusters are arranged in long filaments that reach through space. These filaments are like tendrils of light that embrace large bubbles of empty space called galactic voids. It’s as if the universe were a vast, frothy sea, with galaxies forming the surface of the bubbles.

© Canadian Heritage Information Network, 2003

1.6 Million Galaxies

More than 1.6 million galaxies are shown in this large-scale view of the nearby universe. The closest ones are blue and the farthest ones are red.

2MASS (2 Millimeter All Sky Survey) / CALTECH / MIT

© 2MASS (2 Millimeter All Sky Survey) / CALTECH / MIT.


At the other end of the scale, everything in the universe - people, planets, stars and galaxies - is made of atoms.

Atoms are unimaginably small-about 10,000 billion could fit in the dot at the end of this sentence.

An atom is a tiny nucleus surrounded by clouds of negatively charged electrons. The nucleus, in turn, consists of even smaller protons and neutrons. Neutrons, like their name implies, are electrically neutral, while protons carry a positive charge. Finally, the smallest particles that we’ve found are quarks, which are what protons and neutrons are made of.
At the other end of the scale, everything in the universe - people, planets, stars and galaxies - is made of atoms.

Atoms are unimaginably small-about 10,000 billion could fit in the dot at the end of this sentence.

An atom is a tiny nucleus surrounded by clouds of negatively charged electrons. The nucleus, in turn, consists of even smaller protons and neutrons. Neutrons, like their name implies, are electrically neutral, while protons carry a positive charge. Finally, the smallest particles that we’ve found are quarks, which are what protons and neutrons are made of.

© Canadian Heritage Information Network, 2003

Helium atom

A helium atom has two protons, two neutrons and two electrons.

Planétarium de Montréal

© Planétarium de Montréal


The speed of light

Light moves through space at about 300 000 km per second.

If you flew to the Sun in a Boeing 747, it would take you 20 years to get there, but light travels the same distance in only eight minutes.

Light-years

Cosmic distances are so vast that astronomers measure them in light-years. A light-year is the distance a beam of light travels in a year-about 10 trillion kilometres. The closest star to us (apart from the Sun) is Proxima Centauri, which is 4.2 light-years away. Its light takes 4.2 years to reach the Earth.
The speed of light

Light moves through space at about 300 000 km per second.

If you flew to the Sun in a Boeing 747, it would take you 20 years to get there, but light travels the same distance in only eight minutes.

Light-years

Cosmic distances are so vast that astronomers measure them in light-years. A light-year is the distance a beam of light travels in a year-about 10 trillion kilometres. The closest star to us (apart from the Sun) is Proxima Centauri, which is 4.2 light-years away. Its light takes 4.2 years to reach the Earth.

© Canadian Heritage Information Network, 2003

The speed of light

A beam of light is fast enough to circle the Earth 7½ times in one second.

Planétarium de Montréal

© Planétarium de Montréal


Learning Objectives

The learner will:

  • Recognize that the universe is vast
  • Form a basic concept of the atom
  • Define “light-year”

Teachers' Centre Home Page | Find Learning Resources & Lesson Plans