Projects at the observatory - Distances in Astronomy

In this project participants are able to experience the cosmic distance ladder.

The science of astronomy deals with distances and numbers that can be difficult to imagine. Rather than simply being lectured about the methods used, members of the group will carry out distance measurements using their own bodies. Using the length of their arms and the distance between their eyes, students will make some simple parallax measurements of the distances of stars, which will be represented by balloons.

Participants will then climb the next step on the distance ladder by developing methods, similar to the distance modulus in astronomy, to measure the distance to balloons that are further away.

Finally, they will discover what the colour of the balloon, or the redshift* of a star, can say about how far away it is.

The project can be extended to include computer labs, used in the measurement of distances to other star clusters in our galaxy, or to measure redshift and distances to other galaxies.

* Light is made up of different wavelengths or colours. If light comes from a source that is moving, e.g. a star, the wavelength is either stretched or squashed. The stretching of the wavelength makes the colour turn redder and the squashing makes the colour turn bluer. In astronomy this effect is called redshift.

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