Posts Tagged ‘Caltech’

Yesterday (Thursday 21 January) I was on BBC Radio talking about the possibility of their being a 9th planet in the Solar System (remember, in 2006 Pluto was demoted to being a minor-planet, leaving us with 8). If this suggestion is true, this would lead to our once again having to revise the list of planets that many of us know knew by heart. It would not be the first time we have had to revise it, nor I suspect will it be the last.

The team’s argument is based on anomalies in the orbits of Kuiper belt objects. The Kuiper belt is a region beyond the orbit of Pluto which is the reservoir of short-period comets. I have blogged about the Kuiper belt before here. The authors of this new paper argue that some Kuiper belt objects are having their orbits disturbed by an unseen object, and they suggest that it is an object about ten times larger than Earth.


The Caltech team claim that anomalies in the orbits of Kuiper belt objects suggest that there is a large planet disturbing them

It may come as a surprise to some of you that this is precisely the way that Neptune was discovered. After Uranus’ discovery by William Herschel in 1781, astronomers noticed that it was not orbiting exactly as it should. The simplest explanation was that its orbit was being affected by an unseen planet. Two mathematicians (Frenchman Urbain le Verrier and Englishman John Couch Adams) separately worked out where the disturbing object should be.  There was a race on for astronomers to find the object, and the race was won by astronomer Johann Galle in 1846 working at the Berlin Observatory.

The existence of this new 9th planet is a long way from being proven. The anomalies in the orbits of the Kuiper belt objects is an example of something called a ‘many-body problem’. The gravitational influence of many objects, including the Sun, Jupiter, the other gas giants, as well as other Kuiper belt objects, all have to be calculated to see if there are any unaccounted for effects. This is a horrendously complicated problem, and I am sure this prediction by this team from Caltech will be challenged by others working in this area of research. 


Read Full Post »

Last Thursday (24th of October 2013) I gave a talk to Swansea Astronomical Society. This is the third year in a row that I have spoken in the autumn to this wonderfully active society on a historical theme. Two years ago I spoke about the early history of Yerkes Observatory (I blogged about that talk here), and last year I spoke about George Ellery Hale (my blog on that talk is here).

This year I continued the Hale theme, speaking about the history of Mount Wilson Observatory, which Hale established in 1904 after resigning as Director of Yerkes Observatory. Mount Wilson Observatory is most famous of course for its 100-inch telescope, the telescope used by Hubble (and Humason) to discover that the Universe is expanding. The Observatory is located just outside Los Angeles, and despite the light pollution of LA, it is still a very active observatory. This is mainly due its exceptionally stable air, giving it image quality better than pretty much any other observatory in the continental USA.

My connection with Mount Wilson Observatory is not as strong as my connection with Yerkes, but I was lucky enough to be awarded a Mount Wilson Fellowship in late 1999 and so went to use the famous 100-inch on four separate observing runs in 1999/2000. I was using an adaptive optics system, the plan was to study in unprecedented detail the structure of the scattering of visible light from dust grains in reflection nebulae. Unfortunately we were not able to use the AO system to do this work, as the central stars illuminating the reflection nebulae were too far from the dust regions we wanted to study for the AO system to work. In addition, our primary target, NGC 7023, is located at too high a declination for the 100-inch with its yolk mount to be able to reach. I thus undertook an alternative observing programme of observing close binary star systems to determine their orbital properties, systems which were too close to be resolved with conventional telescopes not using an AO system.

During all of these four observing runs I do not remember seeing the stars twinkle when it was clear (which it was most nights), which is testimony to the incredible seeing the Observatory enjoys. Even way down towards the horizon, the stars remained rock steady to the naked eye. It is because of this exceptional seeing that Mount Wilson was the testing ground for Adaptive Optics systems, and is now the testing ground for optical interferometry, with projects like the CHARA project run by Georgia State University (see this link for more information).

Here are the slides from my talk. I hope you enjoy them, and of course if you have any questions please feel free to ask in the comments section.

Here is a video of my talk. Apologies for the quality.

Read Full Post »

Recently the following list of the World’s best universities was published. The list has been put together by an organisation called QS. I have no idea who this organisation is, but you can read more about them here. The top 20 were, in order

  1. Massachusetts Institute of Technology, USA
  2. University of Cambridge, UK
  3. Harvard University, USA
  4. University College London, UK
  5. Oxford University, UK
  6. Imperial College London, UK
  7. Yale University, USA
  8. University of Chicago, USA
  9. Princeton University, USA
  10. California Institute of Technology, USA

  11. Columbia University, USA
  12. University of Pennsylvania, USA
  13. ETH Zurich (Swiss Federal Institute of Technology), Switzerland
  14. Cornell University, USA
  15. Stanford University, USA
  16. Johns Hopkins University, USA
  17. University of Michigan, USA
  18. McGill University, Canada
  19. University of Toronto, Canada
  20. Duke University, USA

Compare this to this list drawn up by the Times Higher Education(THE) in 2011/12, which has

  1. California Institute of Technology, USA
  2. Harvard University, USA
  3. Stanford University, USA
  4. Oxford University, UK
  5. Princeton University, USA
  6. Cambridge University, UK
  7. Massachusetts Institute of Technology, USA
  8. Imperial College London, UK
  9. University of Chicago, USA
  10. University of California, Berkeley, USA

  11. Yale University, USA
  12. Columbia University, USA
  13. University of California, Los Angeles, USA
  14. Johns Hopkins University, USA
  15. ETH Zurich (Swiss Federal Institute of Technology), Switzerland
  16. University of Pennsylvania, USA
  17. University College London, UK
  18. University of Michigan, USA
  19. University of Toronto, Canada
  20. Cornell University, USA

The first thing that strikes me about the two lists is how Caltech can be 10th in the first list and 1st in the second list. But, also, how consistent the two lists are in terms of their top 10. Of the top 10 universities in the first list, 8 are also in the top 10 in the second list, drawn up by an entirely different organisation. What this probably illustrates is that the differences between the top 10, or even the top 15 universities in the World are minimal, and depend on exactly what is assessed and what weight is given to each element of the assessment.

When I was applying to university in 1981, the only criterion used for the assessment of a university or a department was its research. I had a lot of pressure put on my to apply to either Oxford or Cambridge, as I was deemed to be “Oxbridge” material. I was not keen to go to either, and thankfully for me I found out that the top rated Physics department in the UK at the time was neither Oxford nor Cambridge, but was Imperial College London. I applied to Imperial, without applying to either Oxford or Cambridge, and it was at Imperial I studied my Physics degree. I found it interesting when I arrived there to discover that about 50% of my class-mates had, like me, chosen Imperial above all others; and the other 50% had failed to get into Cambridge (I don’t remember anyone being an Oxford reject).

Nowadays, things have broadened in terms of how departments and universities are assessed. In addition to research reputation, other factors such as teaching quality, staff to student ratio, library and sporting facilities, student accommodation, diversity of students, cost of living etc are also taken into consideration. But, I would wager that the top 15 universities in the World, as assessed by the various organisations who compile such lists, has probably remained largely unchanged over the last 30 years.

In 1993-94, I was lucky enough to spend a year lecturing at Swathmore College in the USA. I must admit, prior to applying there for a job, I had never heard of the place. It turns out it is one of the top 3 private liberal arts colleges in the US. Along with Williams and Amherst, Swarthmore seems to be perennially in the top 3. Certainly I was taken aback by the quality of the students who attend Swarthmore, they had all graduated top of their high-school classes, and had chosen Swarthmore rather than Harvard of Yale or MIT or Princeton because of the excellent undergraduate teaching for which it is renowned. It is a very small college, only 1200 students attended when I lectured there, although this has now grown to some 1500. But that is still tiny compared to the 50,000+ undergraduates one tends to find at the larger US universities. A staggering 5 Swarthmore graduates have won a Nobel prize, which given that only some 300 graduate each year, is a truly incredible ratio. I is also, per student, the best endowed higher education institute in the World. How I wish the Dinsunited Kingdom had undergraduate teaching colleges/universities of such quality.

Imperial College London, my alma mater.

Read Full Post »