Star waves and hue’s Clues: What can light and radio signals tell us about outer space?

Words by Joe Crutwell, Edited by Lucy Eland

At this month’s SciBar, we were treated to a talk by Dr Nick Walker, a lecturer and researcher at Newcastle University. Dr Walker specialises in both astrochemistry (studying the chemical make-up of outer space) and spectroscopy (the study of the interaction between matter and electromagnetic radiation). While these may both sound like quite “out-there” topics in their own different ways, Dr Walker brought everything back to earth with an in-house (or rather ‘in-pub’) demonstration.

Recreating an experiment from 400 years ago, Nick showed us how you can split light into a spectrum of colours using nothing more than a camera and an intense light source. For the work Dr Walker discussed, this intense light source was stars.

In the early 1900’s the director of Harvard Observatory, Charles Pickering, hired a group of women to process astronomical data relating to the spectrum of stars. This data helped create the “Hertzsprung-Russell” diagram, pictured below, that charts stars on a scatter plot based on their temperature and visible light wavelength.


It is possible to learn something about the chemical makeup of an object by studying the colour of light it emits. Nick described how scientists in the 1800’s worked out the chemical makeup of the sun by looking at the wavelengths of the colours it does not emit. This process was extended to other stars to give us a stellar fingerprint of our surrounding space.

This act of breaking up and studying visible light can be performed on other parts of the electromagnetic spectrum, from extremely fast gamma waves to slower radio waves. Radio waves are detected by installations such as the Atacama Large Millimeter Array in Chile, as radio waves are able to permeate through earth’s atmosphere.

These radio telescopes are capable of detecting specific molecules in space. As such, the desire in the scientific community has been to try and detect the presence of organic molecules in space. These molecules are known to be a precursor to life, and may help us answer one of science’s great questions. Did the building blocks of life come into being on earth, or did they land from outer space?

These questions are still to be answered, but spectroscopy is on the case. Telescopes looking at the infra-red spectrum can tell us about stellar dust, the molecules that make up stars. Dr Walker stated that this dust may help us understand where all this complex chemistry originates. Various probes have been sent into space to examine this cosmic dust, including the Cassini probe, which recently was sent crashing into Saturn at the end of it’s twenty year mission.

The next SciBar will be examining one of the most complex products of this sophisticated organic chemistry, our brains! More specifically, Dr Rhys Thomas from Newcastle University’s Institute of Neuroscience will be giving a talk on epilepsy and pregnancy. Join us on the 29th of November!


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