A Sense of Scale Page 4

250 light years

We increase the region to a radius of 250 light years. This contains the 1500 most luminous stars, most of which can be seen from Earth with the naked eye.

The total number of stars within this region is about 260,000. This region is only a tiny part of our galaxy.

In the diagram to the right individual stars have a size of about one pixel on your computer screen. If they would be plotted at the true scale of this diagram, individual stars would have a size of about one tenth of a millionth of a pixel!

Image: Atlas of the Universe


In our scale model this region has a radius of 2,370 km. In New Zealand that is the maximum North-South distance in the country, from Cape Reinga to the bottom of Stewart Island.

Can you find a similar reference in your country? Note that this is only the radius of the bubble, so its diameter is twice as much. And this sphere contains about 260,000 grains of sand. These would fit in a 125 ml glass.





Hyades open cluster is about 150 light years away in the constellation Taurus. The bright red star is Aldebaran, which is a foreground star at a distance of 60 light years. In the bottom left we see the Pleiades open cluster at 440 light years, hence outside the range of the diagram above.
This is the view from the Southern Hemisphere.
Photo: Alson Wong (edited).