Developments in Gravitation and Cosmology - Professor Bob Lambourne, Open University


Not since Galileo in 1610 made his ground-breaking discoveries using the newly invented telescope, have we been at such a scientific threshold - a new age of astronomy. Such was the view of our Vice-President, Professor Bob Lambourne, in his February 2018 lecture to our Society. For not only were gravity waves, originating from two colliding neutron stars 130 million light years away, detected on 17th August 2017 (GW170817) by the LIGO interferometers in Hanford and Livingston, and the Virgo interferometer near Pisa, but also parallel observations were made all across the electromagnetic spectrum.

Professor Lambourne started his lecture reprising material he had presented to the Society in February last year: Newtonian –v– Einsteinian theories of gravity, Interferometry and LIGO, a brief history of the universe. He then went on to describe the discovery timeline of that neutron star collision detection on 17th August last year.

1.7 seconds after the gravity wave event, a gamma ray burst was detected by the NASA/DoE Fermi space telescope. 6 minutes later the Virgo observatory confirmed the LIGO data (it had taken time because the Virgo detection was very weak, being close to one of the instrument’s blind spots). 40 minutes after the event, the gravity wave alert was sent out to the astronomical community. 5 hours later Virgo and LIGO data were combined to determine the source direction of the original neutron star collision – somewhere near the elliptical galaxy NGC4993 near γ-Hydra. Now optical telescopes could get to work and after 11 hours the Swope 1-metre telescope spotted the collision – the galaxy’s red shift (z = 0.009) put it at a distance of 130 million light years mirroring the gravitational wave data. 15 hours after the event, the Swift satellite reported a bright UV emission. 2 weeks later there was X-ray data. Interestingly, but rather disappointingly, the Ice Cube Neutrino Detector at the South Pole failed to detect anything.

All this takes place rather fittingly almost exactly a century after the birth of modern Cosmology; it heralds the birth of multi-messenger astronomy and hopefully will give us new insights to things like gamma-ray bursts, binary star evolution, heavy element synthesis – and, who knows, even dark matter! “There is a huge revolution in progress” Professor Lambourne concluded “This is a great time to be interested in astronomy”.

Sandy Giles

Variable Star Research using SuperWASP - Prof Andrew Norton, Open University

 Professor Andrew Norton and WAS' DR Sandy Giles

Professor Andrew Norton and WAS' DR Sandy Giles

Prof Norton and his colleagues certainly took advantage of the data harvested by SuperWASP telescopes when advancing our knowledge of variable stars. The Wide Angle Search for Planets (WASP) is an international consortium of several academic organisations primarily performing an ultra-wide angle search for exoplanets using transit photometry. Two continuously operating observatories in the Canary Islands and South Africa cover the Northern and Southern Hemispheres, and simultaneously monitor many millions of stars at magnitudes 8 to 15 using eight wide-angle cameras.



(The telescopes are about fifteen years old now and Prof Norton amused us with the story that in the early days, while trying to eke out their research budget, they were compelled to buy the Canon 200 mm f1.8 lenses in just one’s and two’s. Unfortunately Canon stopped making them before the two telescopes were completed and all remaining stocks were bought up by a single buyer who put them up on e-Bay for sale. Fortunately they were able to persuade the university’s Purchasing Department to bid for them and hence complete the instruments!)

So though the primary aim of WASP was to monitor stars for exoplanets, there was a wealth of other data which could be put to good use on variable stars. And we’re talking big data here! Using a Linux computer cluster, initially 30 million stars were identified with apparent periods of variation. Then, using specially written software to automatically filter out unwanted interferences, 771,000 stars were found to have valid periods. And out of this work emerged a number of discoveries.

For example, 143 short period eclipsing binaries with periods of less than 5½ hours were discovered – only 12 were known previously. And the orbital period of many binary stars varies, which may be caused by the presence of a third massive body in the system. They studied the period variations in 13,927 eclipsing binary candidates and observed sinusoidal period changes, strongly suggestive of third bodies, in 2% of cases; however, linear period changes were observed in a further 22% of systems, likely to reflect longer-term sinusoidal period variations caused by third bodies. But this is only scratching the surface of how stars are organised. One binary pair turned out to be a doubly eclipsing quintuple low-mass star system, with a group of three stars orbiting another group of two!

So just as we are now discovering that planets associated with stars are in fact commonplace, it now seems single stars are in a minority, especially at higher masses. And the notion that binary stars have planets is not far-fetched either.

Much to ponder after this technical but, judging by the large number of questions asked, very engaging lecture.


13 Journeys through Space and Time: Christmas Lectures from the Royal Institution - Colin Stuart


When Colin Stuart asked the audience how many people had listened to the Royal Institution Christmas Lectures, a large number of hands went up. When asked how many had actually attended one for real, well, I put my hand up though I didn’t notice whether there was anyone else. Those of us who listened through our childhood to these lectures remember them with fondness, and certainly my interest and eventual occupation as a scientist owe much to the quality and enthusiasm of the selected speakers over the years.
Colin Stuart is an astronomy speaker and author whose books have sold more than 100,000 copies worldwide. He has written over 100 popular science articles for publications including The Guardian, New Scientist, BBC Focus and the European Space Agency. In recognition of his efforts to popularise astronomy, the asteroid (15347) Colinstuart is named after him.
The Christmas Lectures have run every year since 1825 (with a brief pause between 1939 and 1942 and between 2005 and 2006). They were the brainchild of Michael Faraday who gave the first one; his idea was that the talks should be aimed at children and should include as many practical demonstrations as possible. Colin Stuart set out to discuss thirteen of the lecture series over the years. But to a large extent, the actual content of those lectures was not the key point of interest. It was those snippets of science and the scientists that he learned about during his researches which provided the main fascination.

  • For example Robert Ball’s 1881 series. At that time Ball didn’t know what powered the Sun; the Moon, he stated, was too far away for Man ever to get there; there were canals on Mars. More fascinating was the fact that communications in those days were so slow that letters between scientists travelled too slowly to make important announcements (for example about sightings of comets). The scientists of the day devised an ingenious coding system employing a dictionary to exploit the Telegram Service to communicate this type of information.
  • Herbert Hall Turner in his 1905 lectures opined that Sun Spots were bruises inflicted on the Sun by Comets!
  • Harold Jones’s lectures on “Astronomy in our Daily Life” was the first to be recorded by Pathé. The rapt interest and enthusiasm shown by his young audience was no different from today’s youngsters.
  • In 1970, Sir George Porter used a model time machine. It was so large that a window in the Institute had to be removed to allow the model to be brought in and out using a crane!
  • The economies (or rather the lack of them) for Carl Sagan’s 1977 series drew some surprise, but the extract shown of Sagan entertaining two young audience members to afternoon tea on Mars was particularly heart-warming, just so typical of the very practical nature of all these lectures. Colin Stuart’s hunt for Sagan’s assistant, Dr Arun Aggarwal, was also charming.

Colin Stuart’s book (of the same title as this lecture) goes into a lot of detail and contains many fascinating and humorous stories about the lectures. This was a gentle, entertaining and confidently delivered lecture which our audience of about fifty enjoyed enormously.


Lecture by Professor Chris Lintott – “Is the Milky Way Galaxy Special?”


“Intriguing”, “Stimulating”, “Skilfully explained”, “Superb”, “Funny”. Just some of the comments we received after Chris Lintott’s highly entertaining, thought-provoking and informative lecture about our Milky Way galaxy and its place in the universe.
We have tried for a number of years to get this acclaimed astronomer to come to speak to us – often his commitments such as the BBC’s “Sky at Night” or “Stargazing Live” took him away from us. But this time he was able to come. And it was worth the wait!
He gave a very personal view on his approach to astronomy – basically, making interpretations of simple observations of the sky to decide things about the universe. Why, for example does the Milky Way appear the way it does? William Herschel in the 18th century was one of the first to map the stars in our galaxy, though he didn’t know he couldn’t see all of them. It took the Spitzer Infra-red Space Telescope to build a proper map, showing our place in the universe and determine that our galaxy had spiral arms – oh, and a bar (“Things are looking up” someone nearby remarked!)
But is our galaxy different? Lintott described how in 2007 he and his colleagues started to classify galaxies just on the basis of their appearance (e.g. spiral or elliptical). It turns out that humans are better than machines doing this and one student spent a whole year classifying 50,000 of them – but information was needed on another 900,000! Enter Galaxy Zoo, the crowd-sourced astronomy project which invites members of the public to assist in the morphological classification of large numbers of galaxies. The work was completed in months and duplication of observations helped clear up anomalies.
Out of this emerged the Galaxy Colour-Magnitude diagram (analogous to the Hertzprung-Russell diagram for stars) and this is where our galaxy is unusual – it’s green (most are red or blue) and it’s massive for its colour – in this regard we’ve had an unusual history. Nor is our galaxy as active as it should be, albeit it may have been more active as little as 25,000 years ago. Which is a very short time astronomically speaking. Observations of Fermi Bubbles in our galaxy suggest that the black hole at the centre may switch itself on and off on very short timescales. So maybe we are special.
On the other hand, there is data to show that about thirty other galaxies have gone from active to silent in the last 50,000 years. Maybe the Milky Way is not abnormally quiet… we’ve just caught it at a quiet phase.
The information we have at present is conflicting. We need to get Professor Lintott back again, maybe in year or so, when more data will be available. There’s no doubt everyone who attended this lecture would like that!