Archive for October 11, 2017

Post-Planck Cosmology: Day 3

Posted in The Universe and Stuff with tags , , , , on October 11, 2017 by telescoper

Before carrying on with my daily updates from this meeting on Post-Planck Cosmology I’ll just remark that this is a great venue: it has all the facilities necessary to keep a group of cosmologists happy…

At the tea break this morning I managed to find a shot that included all four of the statues in the main quadrangle too:

This morning kicked off with Roy Maartens discussing the cosmological potential of the Square Kilometre Array and other future galaxy surveys, one of his main points being the benefit of using multiple tracers to beat down some of the problems with single surveys.  The first phase of this project, SKA1,  will deliver 10 million redshifts with z<0.6. With SKA2 that will go up to 1 billion galaxies out to z<2, but many things can be done without redshifts using intensity mapping. SKA1 is some way off, but the precursor `Meerkat' consisting of 64 × 13.5 metre dishes will be hopefully starting next year in South Africa.

We then had a series of talks about reionization and the formation of the first stars, an epoch usually referred to as `Cosmic Dawn' or `First Light', taking us into lunch.

In the afternoon we had talks loosely grouped around the theme of `classical cosmology' – using geometric or other probes to study the expansion history of the Universe. This session included a talk by Chris Messenger of the LIGO collaboration about the beginnings of gravitational wave cosmology, though as the current generation of detectors is only sensitive to relatively nearby sources for the time being the main effort will be devoted to distance scale measurements, attempting to measure the Hubble constant directly without the need for the traditional distance ladder.

The last part of the day was devoted to a panel discussion, chaired by Francois Bouchet that was interesting and wide-ranging but largely motivated by responses to Paul Steinhardt's talk last night.

Now, no conference dinner to tear me away tonight – but I do have to finish my talk, which is at 9am tomorrow – so that will have to do for now. Toodle-pip!


Memories of Mumbai

Posted in Biographical with tags , , on October 11, 2017 by telescoper

My first trip to India was in early 1994 and I passed through Bombay (as it was then called) on my way to and from Poona (Pune). My flight from London to Bombay arrived at about three o’clock in the morning and I was greeted outside the immigration area by a young man holding a sign with my name on it who had my train tickets for the next leg of the journey. The train didn’t leave until 6.30am so he asked me what I wanted to do until then. I said I thought I would just go to the station if it was open and wait there. He looked surprised, but said that, yes, the station was open all night. He then kindly offered me a lift in his car as he was heading home and would be going roughly in that direction.

When we got to Bombay Victoria I realised why he had been surprised. I had assumed the station would be fairly empty and I might be able to sleep on a bench or something. When I walked into the concourse it was jam-packed with people sleeping all over the floor. I wandered in sheepishly, the only westerner to be seen, and started to look for what platform my train would be leaving from. Immediately I was surrounded by beggars – women with small babies, cripples, people with gruesome scabs and sores – all pushing me around and pleading for money. Then a teenage boy tried to lift my walkman from my pocket and I started to feel not just uncomfortable but scared.

Pretty soon, though, an official from the State Railways saw my predicament and came to my rescue. Delivering numerous clips around ears he speedily liberated me from my oppressors, took me to into a small kiosk situated on the platform, and offered me a cup of tea. It had far too much sugar in it, but I drank it gratefully anyway. He asked me where I was going, and I told him. He was initially suspicious, I think, because the primary place westerners tended to visit in Pune those days was the Ashram run by Bhagwan Shree Rasjneesh where his disciplines were encouraged to participate in unrestricted sexual activities. When I told my friend from the railways that I actually going to visit IUCAA, which at that time was run by the famous Professor Narlikar, he beamed with relief. I think he wasn’t unique amongst Indians who thought that Rasjneesh was a fraud and his disciples gullible idiots.

It turned out that the train I was to take to Pune was actually already in the station but was being cleaned. Since they cleaned the first class compartments first, I was allowed to get on the train early, about 4.30, and immediately nodded off. I only woke up when the train pulled out of the station and started on its journey up towards the Deccan plateau.

I enjoyed the journey enormously, partly because the train was slow enough to allow me to take in all the sights, and partly because I was sharing a compartment with a very friendly Indian couple (a professor of engineering and his wife). They had done the customary thing when on a long railway journey in India, which is to consult the list of passenger names posted on the platform before the train left the station. When I woke up as the train left the station, they greeted me by name and introduced themselves. It was a refreshing change from the United Kingdom, where it is apparently forbidden to talk to strangers on a train.

I stayed about a month in Pune working with a colleague, Varun Sahni, on a lengthy article for Physics Reports. When that was over I had been invited to visit the Tata Institute for Fundamental Research in Bombay for a few days on my way home, so I got the train back to Victoria. Arriving on time, I left the train to be confronted by a crowd of small boys who tried to convince me that there were no taxis but that they would arrange one for me for a price of 200 rupees. That was way over the odds for a taxi (at the time) so I laughed and said no thanks.

Proceeding out of the station to the taxi rank, I realised that they had been telling the truth. All the taxis in Bombay were on strike that day. I started to panic. How am I going to get to TIFR? Then I remembered that I was to have asked the taxi driver for “Navy Nagar Bus Stop”, which is right next to the guest house I was supposed to stay in.

I thought that if there’s a bus stop there must be a bus, so I found a policeman and asked him where the buses went from. He gave me very clear directions and told me I needed the Number 11. I found the stop without much difficulty, but then there was a hitch. The buses themselves were red double-decker Routemaster types just like those you could find in London. Unfortunately, though, the numbers were written in Marathi script which I couldn’t read. Only when a bus went past did I see that the arabic numerals “11” were written on the back. A few minutes later I was joined at the bus stop by an Indian guy so I asked him if he could tell me the numbers of the buses as they came into view. He asked me where I was going, so I told him and it turned out he was going there too. Sorted.

On the bus I sat with my luggage around me and the front of the lower saloon facing backwards. All the locals peered at me like I was an exhibit in a museum, but most of them smiled. A couple of stops into the journey an old man got on wearing a scruffy coat. He looked rather poorly and had some sort of skin condition. He sat facing me and started scratching himself through his coat. I started to feel quite uncomfortable because this performance went on for some time. Then he started to unbutton his coat as if he was going to take it off. It was then that I realised the cause of his discomfort as a chicken poked its head out.

The bus was quite slow and the journey quite long so, when I finally got to the TIFR guest house, it was quite late. When I found the building, I was pleased to see my host, a physicist called TP Singh, in the lobby talking on the phone. He had his back towards me and was in the middle of a heated conversation, so I waited until he had finished before introducing myself. After a few minutes he put the phone down and turned around, so I offered my handshake and said hello.

He had a look of complete confusion on his face which gradually gave way to relief. “Peter!”, he shouted. “How did you get here?”

I got the bus, was my answer. It turned out he had found out in the afternoon (when I had already left Pune) that there would be no taxis,  so he had sent the TIFR car and driver to meet me at the station. I hadn’t seen the driver amongst the crowds and wasn’t expecting to be met anyway. In those days I didn’t have a mobile phone so there was no way of warning me about it. After scouring the station, the driver had returned to TIFR and reported that I was missing. When I had arrived at the guest house, my host had actually been on the phone to the local police in order to report me lost.

It was during this short visit of three days or so before flying back to London that I behaved as a tourist although I was taken around by students and staff from TIFR which was nicer than the more usual guided tour. I visited the Gateway to India, had tea at the Cafe Leopold, and took a boat to Elephanta Island.

Mumbai (as it is now called) is an enormous, bustling city in which extreme wealth and abject poverty can be found in close proximity and where religious tensions are never far away. Riots are fairly commonplace and there are powerful grievances between the different social groups and claims of police corruption. The sheer scale of the place means that no casual visitor can hope to understand what it  is really like to live. But my visit there left me with an impression of a city full of energy and determination in which there is much kindness to be found not far below the surface.