The Science of the Black Hole, and Its Significance and Place in the Universe, by Professor Derek Ward-Thompson

As we move towards the spring equinox for 2026, the Flamsteed Astronomy Society gathered again at the National Maritime Museum Auditorium for its main March lecture, marking another well-attended and engaging evening in this season’s programme.

Attendees were welcomed by our host for the evening, Barry Cassels, who opened proceedings with thanks to the organising team, museum staff, and those providing refreshments. There was also appreciation for members’ continued contribution of images for the opening slideshow, which again showcased some remarkable captures of both deep-sky subjects and more earthly aurorae.

Barry was our host for the evening, with Chris Sutcliffe giving a short talk on the night sky this month. Pictures by Bobby Manoo.

With the evening underway, we began with a short ‘The Night Sky This Month’ observational talk from returning contributor Chris Sutcliffe. Picking up from the previous month’s discussion on comets, Chris provided an update on current comet sightings. He included a recollection of a memorable observation flight he took from Gatwick Airport to view Halley’s Comet back in 1986 - complete with certificates and even whisky for those on board. He also highlighted current objects of interest in the night sky, including Uranus and Jupiter in Taurus, and Venus appearing low on the horizon later in the month. The timing of the spring equinox and key lunar phases were also noted.

We then moved on to the main talk of the evening, given by our guest speaker, Professor Derek Ward-Thompson. As Director of the Jeremiah Horrocks Institute and a member of the Event Horizon Telescope collaboration, Derek brought both expertise and first-hand experience to the subject of galaxies, black holes, and cosmology.

Professor Derek Ward-Thompson, during his talk to the Flamsteed. Pictures by Bobby Manoo and Paul May.

He began by taking us back through the historical development of astronomy, from the early cataloguing work of Charles Messier - whose frustration at confusing comets with other ‘fuzzy’ objects provided the original motivation for his catalogue - through to the extensive surveys carried out by William and Caroline Herschel, and later John Herschel in the southern hemisphere. These efforts ultimately led to more comprehensive catalogues such as the New General Catalogue, laying the groundwork for modern observational astronomy.

From cataloguing, the talk moved naturally into classification. Hubble’s well-known tuning fork diagram was introduced, though with the important clarification that it does not represent a simple evolutionary pathway. Instead, modern approaches classify galaxies by properties such as colour and luminosity, with systems distributed across the “blue cloud,” “red sequence,” and the so-called “green valley.” Observations now suggest this is not a strict transition but a more continuous spread - perhaps less a tidy diagram and more a reminder that galaxies, like many things in the universe, can be quite variable in structure.

The discussion then expanded to encompass the scale of the universe itself. Hubble’s observations of redshift provided the first clear evidence that the universe is expanding, forming the basis of what we now call the Big Bang theory - ironically named by Fred Hoyle, who was not, in fact, a supporter of the idea. Using the familiar analogy of an expanding balloon, Derek illustrated how this expansion occurs uniformly, with no privileged centre.

A packed lecture theatre for Derek's talk. Pictures by Bobby Manoo.

Attention turned to the problem of dark matter. Unlike the solar system, where orbital speeds decrease with distance, galaxies exhibit flat rotation curves - stars moving at roughly constant speeds, regardless of their distance from the centre. This observation implies the presence of a substantial amount of unseen mass, now understood as dark matter, quietly dominating galactic dynamics while remaining frustratingly invisible.

Bringing the focus closer to home, we examined the Milky Way itself. Once thought to be a standard spiral galaxy, it is now recognised as a barred spiral, with its central structure revealed through infrared observations, capable of penetrating interstellar dust. This dust, composed of fine silicate and carbon-based particles, obscures visible light but allows astronomers to study otherwise hidden regions of the galaxy - rather helpfully turning what was once an obstacle into a tool.

From there, Derek guided us progressively inward, from the full extent of the Milky Way - spanning around 100,000 light-years - down to its central regions. Structures such as the central molecular zone and circumnuclear disk were described, along with the complex magnetic fields present near the core. At the very centre lies a supermassive black hole, recently imaged through a global collaboration, providing a striking contrast to smaller stellar black holes formed from collapsing stars.

We then broadened out again to consider the different types of galaxies observed across the universe. These include elliptical systems ranging from near-spherical to highly elongated forms, lenticular galaxies with disk-like structures but little star formation, and spiral galaxies classified by the tightness of their arms and the presence of bars. Irregular galaxies, such as the Magellanic Clouds, further highlight the diversity of galactic forms.

This diversity is often shaped through interaction. Galaxies exist close enough to one another for gravitational encounters to be relatively common on cosmic timescales. Examples such as the Whirlpool Galaxy, the Antennae Galaxies, and various ring systems illustrate how these interactions can distort structure and trigger intense periods of star formation. Some of the more complex mergers - aptly described as “train wreck” galaxies - serve as a reminder that even on the largest scales, the universe can be rather chaotic.

In the final part of the lecture, we stepped back to consider the largest structures in the universe. Galaxies are organised into groups and clusters, which themselves form part of even larger superclusters connected by vast filaments and separated by voids. While the Cosmological Principle suggests that the universe should appear uniform on sufficiently large scales - “rather like a well-stirred soup,” as Derek put it - recent discoveries of extremely large structures challenge this assumption and have prompted renewed discussion within the scientific community.

Derek concluded by emphasising both how far our understanding has progressed and how many fundamental questions remain, particularly in areas such as galaxy evolution, dark matter, and the large-scale structure of the universe. He also encouraged the audience to continue engagement through questions, further study, and participation in upcoming meetings and research discussions.

The lecture was met with warm applause, bringing another successful and thought-provoking evening for the society to a close.

Photos from the evening (by Bobby Manoo and Paul May):