We had an excellent talk by Dr Samantha Lawler, entitled: Planet 9 or Planet Nein? Discoveries in the outer Solar System. This was followed by an in depth ‘Sky in May’ presentation by Alan Pickup and then for members only, our president, Andrew Farrow gave a talk on a beautiful old telescope from the society (information available for Members).

Dr Samantha Lawler is from Campion College and the department of physics at the University of Regina in Saskatchewan, Canada. Her research has been analysing outer Solar System bodies found using image data from the large telescopes from the Observatories on the summit of Mauna Kea in Hawaii.

Samantha’s lecture was a detailed and fascinating technical explanation of what astronomers understand about the bodies in our outer Solar System, discussing theories for their formation and their connection to help us understand further about the theory for the formation and position of our major Planets and so called ‘Dwarf planets’ within the Solar System. There was detailed discussion about the ‘elusive’ Planet 9 and how herself and other astronomers have gone about finding these outer solar system objects with associated challenges and difficulties.

We are introduced to Kuiper Belt Objects (KPO’s) and Trans Neptunian Objects (TNO’s), and given an overview of the original object found and classified as one of these – Pluto. Pluto is described in detail and we are taken on a journey of our understanding of Pluto from its discovery in 1930 to the beautiful World like images showing water ice and Nitrogen ice glaciers from the amazing fly past by the New Horizons probe in 2015.

After explaining why Pluto had its status downgraded to being a ‘Dwarf Planet’ (due to the finding and analysis of a further KBO – Eris), Samantha introduced us to the vast scale of our Solar and Outer Solar System. We are given an extremely clear understanding of the incredible distances, orbits, and relative positions of our inner Solar System to the far away Kuiper Belt and extremely distant Oort Cloud (which is around half the distance to our next star!).

We were then shown and explained how Planets and planetary bodies exhibit connections such as mean motion resonance. (Interestingly we were reminded of the famous Dr Gladys West who has only recently been accredited for performing the mathematical computations for the determination of the special orbit of Pluto and its mean motion orbit resonance connection with Neptune, which she worked on and calculated back in 1964.)

Samantha then described her own research as part of the Canada – France – Hawaiian team to discover many further TNO’s from ‘The Outer Solar System Origins Survey’ (OSSOS). The survey made 840 TNO discoveries and the vast difficulties and challenges of finding TNO’s were discussed with detailed descriptions of her modelling and bias assumptions. Subsequent theories are then shown for the orbits of these outer Solar System Objects, and this includes a number of possible theories for the elusive Planet 9!

The lecture is rounded up by discussing future planned surveys for finding and mapping more TNO’s and KBO’s, one of which is using the soon to be completed Vera C. Rubin Observatory. This included some very topical discussion on the difficulty for finding these very distant KBO’s which have a brightness magnitude of 25 and are therefore 15 million times fainter than a typical SpaceX Starlink Satellite!

(Samantha expressed her passion about preserving our dark skies and we heard that there are currently +/- 1500 SpaceX Starlink satellites in orbit and by the end of 2021, SpaceX will have placed 50 % of all active satellites. We are told that SpaceX has permission for 12,000 satellites and plans to expand to a whopping 42,000! SpaceX is just one commercial company launching satellites and many more companies are soon to come online. Samantha discussed the need for urgent new modern legislation for commercial satellite ventures in space and she warned us about the loss of our beautiful night sky by these ever-increasing bright satellites and their detrimental effect on future astronomy).

All in all, the talk was superb, and, as with many astronomy theories (when looked at in detail), we are left with a feeling of yet again… ‘that there is so much out there that we need to still understand!’

Alan Pickup then gave us a very informative and knowledgeable talk on the Night Sky in May which as Alan does, included some real gems of knowledge as he navigated us through the Heavens!

In addition to describing the changing constellations and general ephemeral data for the Sun, moon and planets, Alan described the Eta-Aquarids meteor shower and its origins before describing in detail about the new Nova discovered between Cassiopeia and Cepheus. This is Nova Cassiopeia 2021 and a beautiful image of it was shown as Ian Smith had captured it when imaging the Bubble Nebula.

Alan then wonderfully explained with excellent illustrations how a Nova forms with explanations of Nova light curves. There was again some talk about light polluting satellites and secret military satellites, before an update on Comet ATLAS (C/220 R4) and its possibility to view.

Alan rounded off his talk by focusing on the constellation, Corona Borealis (the northern crown), in which he described two interesting variable stars which it contains: R. Corona Borealis and T. Corona Borealis. It was another excellent talk by Alan, which should not be missed!

Will Joy