Disturbing the Universe

David L Clements, science and science fiction


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An Academic Rite of Passage

Today I get to be the internal examiner for a PhD. This is an unusual rite of passage that all those aspiring to a doctorate have to undergo. The procedures are different in different countries, and even different universities in the same country. In the UK, the student and two examiners – one internal, one external – are sealed in a room for an indeterminate period, and the student is asked questions on not only their thesis but anything else the examiners deem appropriate. This can certainly be stressful, but in the best cases it becomes a scientific discussion between equals.

In other countries the vivas may be public, in which case woe betide the examiner who asks a difficult question in front of the student’s parents, and may include specific things outside the nominal remit of the thesis. I particularly like the Dutch system whereby the student must make, and be able to defend, a certain number of propositions several of which have to be outside their field. An good example of this from a Dutch astronomy thesis I read (they’re published as books and circulated to people who might be interested in them) was the proposition that ‘glaciologists who drive up the mountain to do their fieldwork are biasing their own research’.

So that’s how I’m spending my afternoon.

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The Night with No Sky

There have been rumours rumbling around for the last few weeks, and it was something we were all worried would happen once Patrick Moore died, but the Daily Telegraph and The Guardian have now broken the story that the BBC is planning to cancel The Sky at Night in the New Year. An alternative would be to revamp the series, but  this would have to be handled very carefully. Revamps of long running science programmes, such as Time Team, can all too easily go disastrously wrong. The Sky at Night has a loyal following of about 250000 viewers and currently has such a tiny budget that the science content is king. Attempts to push to a larger audience and more flashy presentation will risk ruining that dynamic, which has been established over 50 years.

Other revamps of science shows by the BBC, for example of Horizon some years back (‘real science, real drama’ – argh!) or Material World on radio 4 more recently (with much loved, and very skilled, presenter Quentin thrown on the scrap heap) have not gone well, possibly because the arts dominated BBC really doesn’t understand an audience that wants content and cares less about flashy presentation or flashy presenters.

There is a petition at chamge.org to save the show, so please go there and sign it, but, more than keeping it on air, we need to make sure that its focus remains on content, on the science, and doesn’t get diverted to something that will just put off its highly loyal audience.


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Paranal and the Very Large Telescope

During the middle of July I headed out to Chile to visit the European Southern Observatory’s Very Large Telescope, and to use one of the 8m Unit Telescopes for the first time as a visiting astronomer. Most of the data from the VLT, and all the data I’ve had until now, is taken in Service Mode – someone makes the observations for you and sends you the results. So, despite having had a fair bit of data from the VLT, I had never actually visited. Many other people have, including James Bond, who got to blow up the accommodation block for the telescope in the movie Quantum of Solace.

The trip involves flying to Santiago, the capital of Chile, and then another flight up the coast to Antofagasta, a port of the Pacific coast, at the edge of the Atacama desert, followed by a two hour drive through the desert, past mines and ore refineries, then up into the mountains and to the observatory itself.

The first thing I got to see when I got there was the Residencia, which is really quite something.

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This is the building Bond blew up. Fortunately he left us astronomers somewhere to sleep. He also left a couple of plastic rocks that he hid behind in the movie. There aren’t any real large rocks in the area, so they had to make a few, which they then left behind.

The outside of the residencia is actually less impressive than the interior, which wasn’t shown in the movie. The key thing to remember about the place is that it is in the middle of a very dry desert, so there isn’t much water vapour in the atmosphere. That isn’t conducive to good human health, so the architects decided to do something about it, and built not only a swimming pool inside the building, but also added a small jungle.

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There is also a second small forest which was just outside my room.

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The telescopes themselves are also rather imnoressive. This is a view from the Residencia of the observatory ‘platform’ at the top of Cero Paranal, where the top of the mountain was removed, and four 8m telescopes, the 2.5m VLT Survey telescope, and the auxiliary telescopes of the VLT Interferometer were built.

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Up close one of the unit telescopes looks like this:

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and the inside is like this:

ImageThe telescopes are actually so big, and fill the interior of the domes so well, that it’s very difficult to get over the feeling of size that you have when inside the domes. They also move completely silently – a sign of very high quality engineering.

The overall impression I got from my visit to the VLT is that it is a very well run operation, that knows it’s one of the best observatories in the world, if not the best, and it offers a world class service to its users.

I got some great data, but that’s another post, since there’s a lot more work to be done reducing and analysing it.


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Royal Society Show

Some people seem to think that academics don’t do anything in their long ‘vacations’. I think I’d quite like to go back to term term, as I’ve pretty much been non-stop ever since term ended at the end of June.

The main reason for this, and for my absence from these pages, is that I was running the Planck stand at the Royal Society Summer Science Exhibition. This is a week long extravaganza, where scientists from about 23 selected teams show off their science to the public using exhibition stands set up in the Royal Society’s building, just off the Mall. I’ve been part of shows before, most recently last year’s Herschel exhibit, but this was the first time I had run a stand. The experience of being in charge is very different!

Things that were new to me, at least with respect to running the stand, was sorting the budget, ordering piles of stuff from many different people, getting artwork sorted from our excellent graphic designer and much more. The most stressful, from my point of view, was ensuring that everything we needed was going to be there on time. Mostly this worked, and, at the end of the Sunday before the exhibition opened, we had a stand.

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I think we had one of the nicest stands, though I would say that. We had the centrepiece, which is a 1/4 scale model of Planck, we had videos running above, a Planck version of Chromoscope running around the side of the stand to the right, some examples of flight hardware in a display box, two touchscreens running appropriate games/demos, one of which can be found here, and even a telephone where you can dial up the sound of the Big Bang!

We also had lots of freebies – pens, fridge magnets, bookmarks, leaflets, and even papercraft models of Planck to cut out and build. All of those even arrived on time. However, what was meant to be the piece de resistance did not arrive on time. I ordered small inflatable beachballs with the Planck CMB map printed on them. I was promised delivery the Friday before the exhibition opened and they did not turn up. They also didn’t turn up on the Monday or Tuesday. By the Wednesday, my first full day away from the stand since it started, I was on to the suppliers playing – well not exactly Dr Angry, but certainly Dr Disappointed.

It turned out that the company was disappointed too, since our universes, and several other customers’ orders, were unaccountably being held by HMRC for no readily apparent reason.

They didn’t turn up until the Monday after the show had ended, and there are some production problems with them as well as the delivery issue. Still, some novel uses have already been found for them…

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This is what happens when graduate students get to play with too many universes!

Despite the lack of beach balls, the show went very well. This is what was left of the stand late into the packing up process, as we awaited the van to collect the model.

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According to the Royal Society we had over 11000 people through the front door, and a further 30000 who looked at our web material during the show, and you can still look at the stuff on the web.

The visitors were very varied, from 5 year olds to Fellows of the Royal Society and everything in between, so you have to think on your feet when answering questions. It was a lot of fun, but exhausting to be in charge. I’ll happily stand aside so that someone else can have that pleasure next time.


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Herschel: The End of the End

SPIRE, the UK-led instrument on the Herschel Space Observatory, which was the first instrument turned on during the on orbit commissioning back in May 2009, has now been turned off. It was the last instrument on Herschel to be switched off after the technical tests following the end of helium, and thus the end of observations, earlier this year.

Herschel is over.

Long live Herschel!


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Merger Reveals Secrets of Galaxy Formation: Another Press Release

We had another paper out in Nature this week, a further product of Herschel and the HerMES survey.

This is what ESA had to say about our results:

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A rare encounter between two gas-rich galaxies spotted by ESA’s Herschel space observatory indicates a solution to an outstanding problem: how did massive, passive galaxies form in the early Universe?

Most large galaxies fall into one of two major categories: spirals like our own Milky Way that are full of gas and actively forming stars, or gas-poor ellipticals, populated by old cool red stars and showing few signs of ongoing star formation.

It was long assumed that the large elliptical galaxies seen in the Universe today built up gradually over time via the gravitational acquisition of many small dwarf galaxies. The theory held that the gas in those galaxies would gradually be converted into cool, low-mass stars, so that by today they would have exhausted all of their star-forming material, leaving them ‘red and dead’.

So the discovery in the last decade that very massive elliptical galaxies had managed to form during just the first 3–4 billion years of the Universe’s history posed something of a conundrum. Somehow, on short cosmological timescales, these galaxies had rapidly assembled vast quantities of stars and then ‘switched off’.

One idea is that two spiral galaxies might collide and merge to produce a vast elliptical galaxy, with the collision triggering such a massive burst of star formation that it would rapidly deplete the gas reservoir. In a new study using Herschel data, astronomers have captured the onset of this process between two massive galaxies, seen when the Universe was just 3 billion years old.

The galaxy pair was initially identified in the Herschel data as a single bright source, named HXMM01. Follow-up observations showed that it is in fact two galaxies, each boasting a stellar mass equal to about 100 billion Suns and an equivalent amount of gas.

The galaxies are linked by bridge of gas, indicating that they are merging.

“This monster system of interacting galaxies is the most efficient star-forming factory ever found in the Universe at a time when it was only 3 billion years old,” says Hai Fu from University of California, Irvine, USA, who led the study published in Nature.

“The HXMM01 system is unusual not only because of its high mass and intense star-forming activity, but also because it exposes a crucial, intermediate step of the merging process, providing valuable insight that will help us constrain models for the formation and evolution of galaxies,” adds co-author Asantha Cooray, also from University of California, Irvine.

The onset of the merger has sparked a star-formation frenzy, with the system spawning stars at a phenomenal rate equivalent to roughly 2000 stars like the Sun every year. By comparison, a galaxy like the Milky Way today only manages to produce the equivalent of one Sun-like star per year.

Furthermore, the efficiency with which gas is being converted into stars is around ten times higher than that seen in more normal galaxies, which form stars at much slower rates.

Such a high star-formation rate is not sustainable, however, and the gas reservoir contained in the HXMM01 system will be quickly exhausted, quenching further star formation and leading to an aging population of low-mass, cool, red stars.

Dr Fu’s team estimate that it will take about 200 million years to convert all the gas into stars, with the merging process completed within a billion years. The final product will be a massive red and dead elliptical galaxy of about 400 billion solar masses.

“We were very lucky to catch this extreme system in such a critical transitional phase. It shows that the merger of gas-rich and actively star-forming galaxies is a possible mechanism to form the most massive ellipticals that are observed in the young Universe,” says Seb Oliver from University of Sussex, UK, and Principal Investigator for the HerMES Key Programme, within which the data have been collected.

“This discovery highlights the importance of the vast sky-scanning surveys that were completed with Herschel. In this case, the exceptional source HXMM01 was revealed, which may point to a solution of the riddle of how very massive galaxies formed and evolved when the Universe was still young,” adds Göran Pilbratt, ESA’s Herschel Project Scientist.