The Flamsteed Astronomy Society’s November meeting began with an engaging astronomy news update from our chair, Bobby Manoo. Kicking off the evening, Bobby marked the “Martian New Year”, celebrated on 12th November 2024. He explained that the Martian calendar began in 1955, and this year marks the start of the 38th Martian year. Mars has slightly longer days, called "sols" (lasting 24 hours and 39 minutes), and its 687 Earth-day year - plenty of time to stick to your New Year’s resolutions if you live there!
Bobby also highlighted exciting progress in radio astronomy. Using the MeerKAT array in South Africa, researchers recently uncovered 719 new galaxies hidden in the Zone of Avoidance, a dusty region near the galactic centre. This breakthrough was achieved by detecting neutral hydrogen emissions, revealing that over two-thirds of these galaxies had not been previously identified.
Shifting focus, Bobby discussed the challenges posed by the second-generation StarLink satellites, which emit significantly more radio interference than their predecessors. With nearly 2,000 of these satellites now in orbit, they are creating significant difficulties for radio telescopes like LOFAR. He also noted how heightened solar activity recently caused three Australian satellites from the Binar Space Program to burn up earlier than expected, due to increased atmospheric drag.
To close his update, Bobby reflected on the 10th anniversary of the Rosetta mission’s Philae lander, the first spacecraft to touch down on a comet, and encouraged members to observe Venus, Jupiter, and Saturn in the coming weeks. Venus, in particular, promises to be a spectacular sight as it brightens to a magnitude of -4.2 in December. With members up to speed, the meeting transitioned to the evening’s main event.
The main lecture was delivered by Professor Andy Bunker of the University of Oxford, who presented a fascinating talk on the James Webb Space Telescope (JWST) and its contributions to astronomy. A member of the NIRSpec Instrument Science Team and the JADES collaboration, Andy shared how JWST is pushing the boundaries of what we know about the early universe.
Andy began by describing JWST’s long development journey, its successful launch on Christmas Day 2021, and its deployment to Lagrange Point 2 (L2). He highlighted its impressive engineering, including a 6.5-metre diameter segmented mirror, advanced cooling systems, and a sunshield the size of a tennis court, making it the most powerful infrared observatory ever constructed.
Turning to the science, Andy explained how JWST has detected some of the most distant galaxies ever observed. Through the JADES survey, the telescope has identified galaxies at redshifts of up to z ~ 14, meaning they existed just a few hundred million years after the Big Bang. These findings offer a rare glimpse into the “first light” era, when the first stars and galaxies began forming.
A key focus of the talk was JWST’s spectroscopic capabilities, which allow astronomers to analyse the light from these galaxies in extraordinary detail. Andy explained how this technique reveals their chemical composition, star formation rates, and gas temperatures. The data show these galaxies are chemically simple, with low levels of heavier elements, and their gas is much hotter than that of modern galaxies - all evidence of young, energetic stars.
Andy also discussed the challenges of studying such faint and distant objects. He described methods like the Lyman-break technique and emission-line spectroscopy, which are crucial for confirming the redshifts of these galaxies and piecing together the early history of the universe.
Looking ahead, Andy outlined the potential for JWST to explore the first stars, known as Population III stars, and the formation of supermassive black holes. These discoveries could answer some of astronomy’s most fundamental questions. The telescope’s ability to observe multiple galaxies simultaneously will also accelerate efforts to map the evolution of the universe over cosmic time.
Members appreciated the clarity and insight of Andy’s presentation, which highlighted the transformative role of JWST in modern astronomy. Thanks to Andy for his excellent lecture and to Bobby for his engaging update, both of which made for a highly enjoyable and informative evening.
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