A Sense of Scale Page 5

5000 light years

We are now beginning to see some of the structure of our Milky Way galaxy. The Sun is located in the Orion Arm - a rather slim arm compared to the neighbouring Sagittarius Arm.

Several stars which are located deep within the Orion arm, are visible from Earth with the naked eye. The most notable group of stars are the main stars in the constellation of Orion. All of these stars are bright giants, thousands of times more luminous than the Sun.

There are about 600 million stars within 5000 light years from our Sun.

Image: Atlas of the Universe








This region has a radius in our scale model of 47,000 km, and it has 395 times the volume of planet Earth. The average distance between the grains of sand (stars) in this sphere is 45 km. 600 million grains of sand fit in a 300 litre bin.

So far we have only covered a small part of our galaxy, but we are already far outside planet Earth with our scale model.

A 3D view of the constellation Orion. In the Southern hemisphere we see that upside down.

Animation Freedman and Kaufmann http://bcs.whfreeman.com