11 February 2020
Two centuries of astronomical discoveries are at the heart of Royal Mail’s latest issue, celebrating the 200th anniversary of the Royal Astronomical Society and the British astronomers and astrophysicists who have deepened our knowledge of the universe.
The Royal Astronomical Society, based in London’s Piccadilly, exists to promote the study of astronomy, solar system science and geophysics, a goal echoed by its motto Quicquid nitet notandum(whatever shines should be observed).
Founded on 10 March 1820, with a small membership of largely ‘gentleman astronomers’, the society is now one of the world’s foremost authorities on astronomy and awards a number of prestigious medals and prizes each year, including the Gold Medal of the Royal Astronomical Society.
The eight stamps featured in Visions of the Universe each showcase an astronomical discovery with connections to the Royal Astronomical Society. Stamp one (2nd) features a Cat’s Eye Nebula, a planetary nebula in the northern constellation, first discovered by the society’s original president William Herschel on 15 February 1786, more than thirty years before the founding of the society. The stamp wording reads: ‘Cat’s Eye Nebula is composed of dust and gas’. Huggins’ discover demonstrated that these nebulas were composed of gases and weren’t stellar in nature.
Herschel’s influence is also evident on the second of the 2nd class values, this time showing Enceladus, Saturn’s sixth-largest moon. The wording ‘Enceladus has geysers of water ice and vapour’ is accompanied by a dramatic illustration showing the surface of this moon, whose icy covering makes it one of the solar system’s most reflective objects. It was first discovered by Herschel on 28 August 1789 and two centuries later, was studied at close quarters by the spacecraft Voyager 1and Voyager 2. Investigations continue and in 2018, scientists reported that complex macromolecular organics had been detected on Enceladus’s jet plumes.
The third stamp in the set showcases the well-known black holes of space, labelling them as ‘super dense regions of space’. The subject of countless works of sci-fi literature and film, the possibility of the existence of black holes was first considered by 18th-century scientists, and first published as an interpretation of a region of space from which nothing can escape by David Finkelstein in 1958. It wasn’t until last year that the first ever direct image of a black hole was published, thanks to observations made by the Event Horizon Telescope.
The dramatic illustration on the second of the 1st class values shows a pulsar, a magnetized rotating neutron star which is a relatively recent astronomical discovery, first observed in November 1967 by Jocelyn Bell Burnell and Antony Hewish and later credited as being ‘one of the most significant scientific achievements of the 20thcentury’, whose discovery was later recognised by a Nobel Prize in Physics (but not awarded to Jocelyn Bell Burnell, despite her role in the discovery). Bell Burnell did, however, go on to become president of the Royal Astronomical Society and of the Institute of Physics.
We now move to a phenomenon often visible from earth, the aurora – sometimes referred to as the northern lights or southern lights. Stamp five features the dramatic auroras of Jupiter, described on the stamp as the strongest in the solar system, perhaps not surprising since Jupiter is the solar system’s largest planet and is one of the brightest objects that a human eye can detect in the night sky. The planet is still very much a focus for future scientific research, with scientists working towards the goal of exploring the liquid ocean of Jupiter’s moon Europa.
‘Gravitational lensing occurs when gravity bends light’ reads the wording on stamp six (£1.55), which features a striking illustration of this phenomenon. There is no single focal point to a gravitational lens, but rather a focal line, with this effect being strongly associated with Albert Einstein and his general theory of relativity. We next move to the comet, with a 67P comet shown on the £1.60 value. This clustering of rock, ice and dust can travel at 84,000 miles per hour and has a 6.45-year orbit. It Is part of the Jupiter family of comets and was first observed in 1969.
Finally, we see the Cygnus A Galaxy, described as a powerful source of radio waves on the second £1.60 value. This galaxy is one of the strongest radio sources in the sky and has a supermassive black hole at its core. As with the other discoveries featured in Visions of the Universe, it continues to interest scientists and will be the subject of study for decades to come.
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Click here for your chance to win one of ten Visions of the Universe presentation packs, courtesy of Royal Mail.