The March 2025 Society Meeting talk saw a change of plan, following the late cancellation of the planned event, with our own society member and society Outreach Lead, Hugh Alford, stepping in to give his own talk titled: ‘Space is BIG!’.
Right at the start, Hugh warned us all that he was going to take us on a trip from the Earth right out to the edge of the known observable universe and that this would involve us dealing with scales which we might find difficult to comprehend; especially as space was more nothing than something!. It was going to be a challenge which we all willingly agreed to take and he prefaced the talk with the warning of, “no maths or equations but some VERY big numbers.’
Beginning with a look at what we comprehend as the meaning of the word ‘space’ and quickly introducing some large numbers with relation to the volume of just one cubic light year, we revised the theory of the Big Bang along with the well-known scales of the Solar System as a warm-up to the bigger things to come.
The Solar System moved on to the Milky Way Galaxy quite quickly and numbers and figures came and went and caused pause for thought. There was a quick stop along the way to consider the number of stars/planets that radio signals from Earth may have propagated to in the last 125 years, which was notably small and Hugh expressed no surprise that we had yet to hear any signals from those ‘little green men’!
Then it was out of the Milky Way into intergalactic space, where every other visible light was another galaxy. Respective sizes of galaxy were discussed along the way, with Andromeda considered on its own before looking at our local galaxy supercluster and the distances and volumes of space involved, highlighting those of the massive cosmic voids in between.
The results of the 1995 Hubble Deep Field images had been updated by the James Webb Telescope and an animation of the 2003 Anglo-Australian 2 Degree Field Galaxy Red Shift Survey, along with several others, helped put such results into perspective.
There had been several big scale jumps throughout the talk and this, hopefully, had prepared us for the journey towards how the scale of the universe looked as we reached the magnitude of the vast cosmic web that formed the entirety of what we perceive as the ‘Observable Universe.’
Hugh then put some ‘best guess’ figures to what star and space magnitudes would be involved in such a volume just to try to numb our brains into submission.
Several deductions on his own perceptions of what we had just seen and heard, along with a quote from Stephen Hawking on the value of understanding our own place in the cosmos brought this enjoyable talk to a thoughtful and humorous conclusion.
Prepared by Hugh Alford