Birthday boy Édouard Jean-Marie Stephan was born on August 31st, 1837, in Sainte Pezenne, a commune on the outskirts of the town of Niort, in the Deux-Sèvres department of France. Stephan discovered two asteroids, 89 Julia and 91 Aegina, both of which have been featured in these pages. But it was on the deep sky that he focused much of his attention, discovering more new nebulae than most, and the now famous (as groups of galaxies go) Stephan’s Quintet.
His work did not go unnoticed, and in 1884 he was awarded the Prix Valz by the French Academy of Sciences. A report on the award in the American journal Scientific News described him as “a savant whose discovery of seven hundred nebulae does honor to French astronomy”.
Stephan would have been in good company at the awards ceremony (I have no idea whether they had one or not), as that year’s physics prize went to the great Henri Becquerel, co-discoverer of radioactivity.
Edward Mills Purcell, born August 30th 1912 (died March 7th 1997) was supervisor of the Harvard team responsible for detecting the elusive 21 cm line of neutral galactic hydrogen.
They achieved this by using a home-made horn antenna, built at a cost of just $500, and installed outside the Lyman Lab at Harvard.
Discovery of the 21cm line was important because it allowed radio astronomers to peer through the Earth’s atmosphere with minimal interference and calculate the rotation curve of the galactic spiral arms.
ALSO TODAY . . .
1984 – First flight (mission STS-41-D) of the space shuttle Discovery.
1880 – Asteroid 217 Eudora discovered by Jérôme Eugène Coggia.
1974 – The Astronomical Netherlands Satellite (Astronomische Nederlandse Satelliet) was launched.
74 Galatea (discovered August 29th, 1862) was the third of five asteroids to be discovered by the German astronomer Ernst Wilhelm Leberecht Tempel(comets were more his thing – he found an impressive 21!).
Galatea is a large, dark, C-type main belt asteroid, and if it seems as though every asteroid I mention fits that description it’s because 75% of all known asteroids are C-types, and the main belt contains 93% of all the numbered minor planets.
Two possibilities exist for the choice of the name Galatea. Ovid tells us on the one hand that it was the name of the ivory statue carved by the sculptor Pygmalion, with which he fell in love. But on the other hand he also uses the name to describe a nereid (sea nymph) whose lover, the river spirit Acis was killed by a boulder thrown by Galatea’s jealous suitor, Polyphemus the cyclops. Ovid omits to discuss what kind of aim a cyclops would have.
Enceladus was discovered on this day in 1789by William Herschel. This 500km diameter moon of Saturn has been proven recently to have the most impresive volcanoes in the Solar System. They are cryovolcanoes, so what comes out is cold (in this case water), and study of them has shown that they have been able to project water as far as Saturn itself, as well as providing enough ice to make up the parent planet’s “E ring”.
Enkelados was one of the Gigantes, children of Uranus and Gaia. This particular one, for his sins, was wounded in battle by Athene and buried under Mount Etna. Being buried under a volcano was a common fate for the assorted monsters and giants defeated by the Olympian gods. I suppose it was a handy method for explaining away subterranean rumblings.
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ALSO TODAY . . . .
Asteroid 167 Urdadiscovered in 1876 by Christian H F Peters. George Eric Deacon Alcock MBE was born in Peterborough, 1912.
Asteroid 240 Vanadis was discovered by the French astronomer Alphonse Borelly on August 27th 1884. It is a “C” type asteroid in the main belt, about 94km in diameter, with a day lasting just over 10 and a half hours. It has an absolute magnitude of 9.0.
Vanadis is another name for Freyja, a Norse goddess associated with fertility, love and beauty. Like a lot of Norse deities, she’s a bit quirkier than your average Greek or Roman goddess. Her peculiarities include always having a boar at her side, and driving a chariot pulled by cats. It is from Freyja that those of us who use partly or wholly Germanic languages derive the name Friday. Her alternative name, Vanadis , means something along the lines of “spirit of the Vanir” (a group of deities associated with nature and fertility).
ALSO TODAY . . . .
1962 – launch of the first successful probe to Venus,Mariner 2.
August 26th 1981 was the date on which Voyager 2made its closest approach to Saturn (at 01:21 UT). Voyager 1 had already been and gone 9 months previously, despite being launched second, and between them the Voyager twins greatly increased our knowledge of the most beautiful of all the planets. They found, among other things, that (i) the atmosphere is nearly all hydrogen and helium (Saturn would float in water if an appropriately-sized bath could be constructed); (ii) it is a very cold place (-200 to -300°F); (iii) it’s also a bit blowy (wind speeds recorded over 1,100 mph), and (iv) it rotates every 10 hours 39 minutes and 24 seconds.
It’s hard to say exactly where Voyager 2 is at the moment, because I’m typing this several days before I post it, and a Voyager can get about 30 miles further away in the time it takes me to type the word “miles”. If you want to know, then your best bet is to go to the JPL Voyager Mission Status web page. For now, I’ll round it up to something that only changes very rarely: 121 AU (1 Astronomical Unit is about 93 million miles, so it’s a safe figure for a few weeks).
Today in 2003, Cupid and Mab, moons of Uranus, both of which had been too dim to see on Voyager photographs, were discovered by Mark R Showalter and Jack J Lissauer using the Hubble Space Telescope. Cupid was named after the character in William Shakespeare’s rarely performed and possibly incomplete play Timon of Athens, and Mab after the queen of the fairies who is mentioned in Romeo and Juliet (and as a long-time fan I would also refer you to The Fairy Feller’s Master Stroke on the album Queen II). Mab has unusual hobbies. She drives her chariot (which I believe is made from an acorn) up people’s noses to enable her to influence their dreams, and she is thought to decide who gets infected by herpes simplex.
Neither Cupid nor Mab could be described as impressive bodies. Cupid measures about 18 km in diameter, while Mab is thought to be about 24 km.
Also today, asteroid 84 Klio was discovered by R Luther in 1865. Clio (or Klio or Kleio) was the muse of history. A daughter of Zeus and Mnemosyne, she had one son, to whom she gave the butchly masculine name Hyacinth. Her own name is derived from the verb kleô, meaning to celebrate or make famous.
1889 – Asteroid 287 Nephthys discovered by C F H Peters, and is the last of his incredible haul of 48 asteroids. Nephthys is a large, S-type main belt asteroid, and for a change is named after a character from Egyptian mythology, the daughter of Nut and Geb, and sister of Isis.
I’m going to have to do some digging on Peters, because I find it hard to believe that after 28 years of tracking the things, he doesn’t have an asteroid named after him. I’ve found two so far named after people called Peters, and he isn’t either of them.
Finally today,Voyager 2 made its closest approach to Neptune on August 25th, 1989. This was the end of a bit of a purple patch for NASA. Photographs from the outer planets had enthralled the inhabitants of this one for more than a decade, and Neptune didn’t disappoint. Voyager 2 was able to get some great shots of the planet, including the “Great Dark Spot” which seems to have subsequently vanished. There was also time for a visit to Triton, Neptune’s volcanically active largest moon, thought to be a captured Kuiper Belt object.
Although they didn’t know it at the time, this fly-by marked the point at which every planet in the solar system had been visited (back in the day they still had Pluto on the list, but it would eventually be removed).
The large, dark, C-type main-belt asteroid93 Minerva was discovered today in 1867 by the American-Canadian astronomer James Craig Watson. Minerva was the second of his 22 asteroids. Several occultations of stars by Minerva have been observed since discovery to give an estimated diameter of 150 km. It has recently become apparent that Minerva is in fact a trinary asteroid, with two tiny moons (just 3 and 4km across).
Minerva was the Roman equivalent of Athena, a goddess primarily associated with wisdom, although she did have several other attributes on her curriculum vitae (or resumé if you insist) including music, poetry and magic.
The moons of Minerva have been given names associated with their parent. S/(93)1 is now known as Aegis, after the animal skin worn by Athena, while S/(93)2 Gorgoneion refers to a protective amulet (of the Gorgon’s head) worn by certain deities.
Today’s second picture is the shrine to Minerva at Handbridge in Chester. You can’t see a great deal of detail, and the surrounding stonework is nineteenth century, but it is “Grade I” listed and the only one of its kind in situ in western Europe, so it deserves a mention.
Main belt asteroid 124 Alkesteis an S-type of just over 76 km diameter, discovered on August 23rd, 1872 by C H F Peters from Hamilton College in New York State. The name refers to Alcestis, daughter of the mythological Greek king Pelias, and eponymous subject ofthe play by Euripides which won second prize at the City Dionysia in 438 BC.
The name was chosen by Adelinde Weiss, wife of the Austrian astronomer Edmund Weiss.
We almost have a photograph of today’s birthday girl, although actually it’s a series of images of the star Beta Virginis, the fifth brightest star in the constellation Virgo. This star was occulted (temporarily hidden) by Alkeste on June 24th, 2003. If enough people within the area from which the occultation can be seen make images of the track of the occulted star, these can be combined to give a rough guide to the size and shape of the asteroid. The area in question was a slender 80 or so kilometre slice across New Zealand and southern Australia, but enough observations were taken on the night to give the above indication of Alkeste’s shape.
Asteroid 19 Fortuna, discovered today in 1852, is a large, dark, main-belt asteroid. In fact, it is one of the darkest large asteroids known. It was discovered by John Russell Hind, an English astronomer who was working at the private observatory of George Bishop, having previously been at Greenwich. Hind will hopefully be given the full treatment on his birthday (May 12) but for now I’ll just mention that his wife had the wonderfully Bond girl-esque name of Fanny Fuller.
Fortuna, of course, was the Roman goddess of luck. Being a goddess of fate as well though, the luck she brought couldn’t be relied upon to be of the good variety (an amulet mentioning her was found at Pompeii, for example).
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ALSO TODAY . . . .
1868 – Discovery of asteroid 102 Miriam by C H F Peters. Miriam is named after the sister of Moses. Back in the 1880s asteroids were named after mythological figures, so the choice caused a stir at the time, the inference being that she may not have been a real person.
1882 – Discovery of C-type main belt asteroid 229 Adelinda by Johann Palisa.