North Oxford astronomy enthusiast and retired physicist Geoff Cottrell recently gave an intriguing talk at Chipping Norton literary festival about a new technique enabling the distance between stars to be measured. 

 

Geoff mentioned that he first became interested in astronomy when he was ten years old and received a telescope for Christmas from his father. “It was a really nice reflective telescope” said Geoff  “You could see the moon and its craters in great detail, and we could see Jupiter and its four moons and Saturn, which was amazing for a child.” Geoff has been passionate about astronomy ever since. 

 

When asked why measuring stars is important, Geoff replied “In ancient Greece, the Greeks made maps of the stars for navigation purposes at sea, and keeping time. It started a long time ago before there were even telescopes.”

 

According to Geoff we can now see that “two colliding galaxies, which had never been seen before in great detail, triggered a wave of star formation. The collision triggered a wave of collapse of gas to form new stars.“

 

Geoff made his own device which he uses to illustrate the way astronomers measure distances in the universe. He explained how a light on the gadget represents a particular star, and a meter measures the amount of light falling on the detector. This helps astronomers to estimate the distances of stars because “If you know the brightness of the star intrinsically - how much power it's emitting - all you've got to do is measure how bright it appears to be, and you know the distance to the star. That's one of the main methods of measuring distances in astronomy.”

 

Geoff’s new book “Observational Astronomy: A Very Short Introduction” is an introduction to the universe and astronomy and is published on May 25 by Oxford University Press.