July 27 – Sir George Airy

Today is the birthday of Sir George Biddell Airy, born in 1801 at Alnwick (I think you pronounce it ‘annick’, but don’t quote me) in Northumberland, England.  If you pay a visit, you’ll probably recognise Alnwick from its castle, which has starred in two Harry Potter films, Downton Abbey, Star Trek: the Next Generation and The Black Adder.

Airy shone as a student at Cambridge, probably to the annoyance of his fellows. Like Isaac Newton before him, Airy was a sizar, a class of student whose parents could not afford to pay the full fees, but who were allowed entry on the understanding that they paid their way by working as a servant at the university while studying.

A mere six years after entering Cambridge Airy was appointed Lucasian professor of mathematics, one of the most prestigious academic posts anywhere, held over the years by (among others) Charles Babbage, Paul Dirac,  Stephen Hawking, and the aforementioned fellow sizar Isaac Newton.

Airy made several important discoveries in his time, including a tiny inequality in the motions of Venus and Earth that led to an overhaul of Delambre‘s solar tables.  He also came up with a new figure for the mean density of the Earth.  This was achieved by measuring the change in gravity as one descends into the Earth by using changes in the swing rate of a pendulum at the top and bottom of a deep coal mine. It turns out that at just over 1000 feet down the pendulum ‘gains’ two and a quarter seconds a day. From this, Airy was somehow able to calculate a specific density of about 6.5. Today it is thought to be 5.5.

Today’s picture is A Shell Forge, by war artist Anna Airy, George’s granddaughter.

A Shell Forge (Anna Airy).
A Shell Forge (Anna Airy).

1879  –  Discovery of C-type asteroid 200 Dynamene by C H F Peters.


July 26 – Apollo 15

Today in 1971David ScottJames Irwin and Alfred Worden became the first philatelists in space.  Their attempt to smuggle unauthorised postage stamps to the Moon and back to be sold later did rather put a bit of a downer on the reputation of the fourth Moon landing, which was a shame, because the mission (including the first use of the lunar rover), was otherwise a great success.

Apollo 15 crew (image credit: NASA)
Apollo 15 crew (image credit: NASA)

Apollo 15 was the first to land somewhere other than a lunar mare, and was longer than previous visits, with over 18 hours spent outside the lunar module.  The landing site chosen for Apollo 15 was Hadley Rille, a valley to the southwest of Mons Hadley, a ‘massif’ in the Moon’s northern hemisphere.

1958 – launch of Explorer 4. Launched this day in a blaze of secrecy, Explorer 4 spent the summer of 1958 collecting data on the Van Allen radiation belts. The Explorer family is the longest running series of spacecraft ever, from Explorer 1 in 1958 to Explorer 78 in 2000.

July 22 – Friedrich Wilhelm Bessel

Today is the anniversary of the birth, in 1784 of Friedrich Wilhelm Bessel, the German astronomer who was the first to use parallax to find the distance to a star.  The star in question was 61 Cygni, which Bessel decided was 10.3 light years away (the current measurement is 11.4 ly).  One can only marvel at Bessel’s ability, in 1838, to measure the unbelievably small angles involved.  The feat was somewhere akin to measuring the differences in direction of the left and right edges of a Brussells sprout located about three miles away.

Portrait of Bessel by the Danish artist C A Jensen
Portrait of Bessel by the Danish artist C A Jensen

Asteroid 30 Urania was discovered on July 22nd 1854 by John Russell Hind.  It is a main belt S-type asteroid of about 100km diameter at its widest point.


Urania is the Greek muse of astronomy, a daughter of Zeus, and great-granddaughter of Uranus.  She is usually represented wearing a cloak embroidered with stars.  The allegorical representation above is by the French portrait painter Jean Louis Tocqué.

July 21 – Small Step; Big day

July 21st 1969 is going to take some beating as far as big days go.  I’ve been thinking about it, and it’s just really obvious that nobody has ever done anything even remotely as impressive as walking on the Moon.  The more one thinks about it, the less likely it seems that it was even possible with 1960′s technology (don’t forget that the processors used in the guidance system were smaller than the ones available in home computers just a decade later, and my android phone is obviously from a different planet).

Pretty big shoes to fill (image credit: NASA)
Pretty big shoes to fill (image credit: NASA)

Maybe something to top it will come along eventually (the first gay pope to visit  Mars, maybe?) but in the meantime, here are a couple of other events being commemorated in the enormous shadow thrown by Neil Armstrong’s boots.

1914  –  Discovery of Jupiter’s moon Sinope by S B Nicholsonwhile he was working as a summer assistant at Lick Observatory.  The ninth satellite of Jupiter to be spotted, Sinope was, as I say, discovered in 1914, but didn’t receive a proper name until 1975; until then it was simply “Jupiter IX”.  It was named, along with eight other moons, “on the recommendation of the Working Group for Planetary System Nomenclature” of the IAC.  Nicholson’s discovery was slightly serendipitous, as he was actually photographing “Jupiter VIII” at the time with the 36-inch British-built Crossley Reflector, a device the observatory had bought from it’s previous owner when it became obvious that the skies above Halifax, England, were a waste of a large telescope.

1998  –  RIP Alan Shepard.  Shepard (another of the Mercury Seven) was, as commander of Apollo 14, the fifth man on the Moon, and the first to play golf there.  It’s perhaps just as well that the Americans conquered the Moon.  I doubt the effect would have been quite the same when the first Briton on the surface got his dartboard out.

1961  – Launch of MR-1, the first unmanned spacecraft of the Mercury project.  A spectacular failure, it managed to attain an altitude of four inches in a flight lasting 2 seconds.

2006  –  Discovery of Actaea, the satellite of trans-Neptunian object  120347 Salacia.

July 20 – Sea of Activity

Today was a very big day in 1969, as it was the day on which, at 17 minutes past 8 in the evening, Neil Armstrong and Buzz Aldrin (but not Michael Collins) landed their lunar module in the Sea of Tranquility, becoming the first humans to land on the surface of the Moon.

Apollo 11 Crew (image credit: NASA)
Apollo 11 Crew (image credit: NASA)

There has been a great deal written and said about this event, with which I won’t attempt to compete. I will just say that although the intrepid moon men brought back 21.5 kg of lunar material, the main impact of their visit from the Moon’s perspective was to leave behind several tonnes of extremely expensive scrap metal.

Tranquility from the window of the Lunar Module (image credit: NASA)
Tranquility from the window of the Lunar Module (image credit: NASA)

The Sea of  Tranquility (Mare Tranquillitatis), once thought to be an ocean on the Moon, is a large basalt basin, probably produced by a lava flow following the impact of something quite large, at the time of the Pre-Nectarian epoch, meaning it was formed before the Mare Nectaris.  The Pre-Nectarian doesn’t really have an equivalent epoch on Earth, because any rocks of a similar age down here would long ago have been sucked back below the surface to be recycled.

Looking towards home from Apollo 11 landing site (image credit: NASA)
Looking towards home from Apollo 11 landing site (image credit: NASA)



July 19 – 226 Weringia

Main belt asteroid 226 Weringia was discovered on July 19, 1882 by the great Austrian asteroid hunter, Johann Palisa.  In under 50 years Palisa identified 122 asteroids, Weringia being one of nine he found in 1882.

Weringia is a fairly bright body of 34 km diameter, but little more is known of it.   It is named after the district of  Währing in Vienna.


Today’s artistic offering shows the church of St Gertude in Währing, about 1850, by an unknown artist.

Palisa’s home town (called Troppau then, now Opava) is these days located in the Czech Republic, and the local university at Ostrava thought highly enough of their local hero to re-name their observatory and planetarium after him in 2000.

July 18 – John Glenn

Today marks the birth, in 1921, of John Herschel Glenn, Jr, recently deceased (December 8th 2016) but liver of quite a full life, of Scottish descent (I believe he also had relatives in Sheffield), and born in Cambridge, Ohio.  Reading that sentence back the word “liver” sounds a bit anatomical, but I’m going with it anyway.

Glenn was a member of Astronaut Group 1, more commonly known as the Mercury Seven, the original hand-picked, hard-boiled, right-stuff-infused group of astronauts selected by NASA in 1959, who had a presence in all of the classes of manned American spacecraft of the twentieth century (MercuryGeminiApollo and Shuttle).

John Herschel Glenn Jr, of the clan Glenn-Macintosh. (Image credit: NASA).
John Herschel Glenn Jr, of the clan Glenn-Macintosh. (Image credit: NASA).

Here’s a potted history of some of John Glenn’s achievements:  fighter pilot in the South Pacific, North China and Korea; test pilot; first supersonic transcontinental flight; first American to orbit the Earth; senator (Democrat); oldest person in space.

On a slightly less joyous and happy-birthdayous note, he managed to get himself caught up in the Lincoln Savings and Loan affair, and was for a time opposed to the inclusion of women in NASA’s astronaut program.  That said, I still don’t know how a man who had once had a ticker-tape parade through New York in his honour later managed to lose the vice-presidential race to career politician and sometime lawyer Walter Mondale, a man who would later go on to suffer one of the biggest landslide defeats in US presidential election history.

Walter Mondale is of Norwegian descent, and the ancestral family home is the village of Fjærland, on a tributary of the Sognefjord, which gives me an extremely tenuous reason to end with one of my own photographs, taken a mere ten miles or so downstream from chez Mondale in 2010.

Sognefjord, 2010. (Image credit: me.)
Sognefjord, 2010. (Image credit: me.)

1966  –  Launch of Gemini X (command pilot John W Young and pilot Michael Collins) from Cape Canaveral launch site LC-19.  This was the sixteenth manned American spaceflight.

1997  –  Death of Eugene Shoemaker, astrogeologist, and co-discoverer of comets (along with his wife and David Levy).  Of their combined tally, the most important was  probably Shoemaker-Levy 9, which collided with Jupiter in 1994.

July 15 – Dame Jocelyn Bell Burnell

Today is the birthday of Professor Dame Susan Jocelyn Bell Burnell DBE, born July 15th 1943 in Belfast, Northern Ireland. Dame Jocelyn was the the discoverer of the first four pulsars, and, rather disgracefully, a non-recipient of the Nobel Prize for her efforts, which has annoyed a great many people, although Bell herself has been very forgiving, as one would expect from a good Quaker girl.

1890 – Asteroid 294 Felicia was discovered by Auguste Charlois.


July 14 – Elst-Pizarro: Asteroid or Comet?

Minor planet 7968 Elst-Pizarro was discovered by Eric W Elst and Guido Pizarro from photographic plates taken by Pizarro while he and his brother Oscar were working as assistants with the ESO Schmidt telescope at La Silla Observatory, on July 25, 1979. The discovery was reported by Elst, of the Royal Observatory, Uccle, Belgium, on August 7th. Comet 133P/Elst-Pizarro was discovered by M R S Hawkins and R H McNaught on July 14, 1996.  They are one and the same.

133P/Elst-Pizarro has characteristics of both an asteroid (for a start, it’s in the asteroid belt, with an orbit varying between 2.6 and 3.6 AU) and a comet (it sometimes has a tail). The tail suggests a non-asteroidal icy composition, although it is also possible that this is a rocky body that occasionally expresses dust due to the gas pressure of evaporating ice.  This is where I go off at a tangent to make sure we’re on the same wavelength with the word “express”.  Your small strong coffee is called an espresso because of the way the water is forced under pressure through the beans,  like so much ice from the surface of comet 133P/Elst-Pizarro (possibly) and has nothing to do with the speed of it’s drinking, or the way it makes you rush around like a lunatic for thirty minutes afterwards.  And while we’re on the subject, look up the origin of the name cappuccino. (End of pointless aside.)

The occasional nature of the tail doesn’t do much for E-P’s comet cred. It only tends to appear close to the perihelion of its 5.62 year journey around the Sun.

July 13 – Gamma Cephei Ab

Gamma Cephei Ab was probably discovered on July 13,  1988 by Bruce Campbell, Gordon Walker and Stephenson Yang. But there was, understandably, a certain amount of uncertainty over whether they had, in fact, discovered the first extra-solar planet, so it wasn’t confirmed until more than a decade later.
The star Gamma Cephei is, of course, in the constellation Cepheus, named after a mythological king of Aethiopia. It is a binary system, comprising Gamma Cephei A, a “K” type star (the next most common type of main sequence star after the “M” types) and B, thought to be a red dwarf.

La Délivrance d'Andromède (1679) by Pierre Mignard.
La Délivrance d’Andromède (1679) by Pierre Mignard.

Today’s visual aid is from the Louvre, Paris, and shows King Cepheus (kneeling) and his queen, Cassiopeia, thanking Perseus for freeing their daughter Andromeda.  Completing the collection of Northern constellations, a certain winged horse can be seen palette-bombing in the background.