What caused the ripple in the Microwave Background?

The retreat from light pollution

Edinburgh has a long, esteemed history in the study of astronomy – two to three hundred years. A snowflake in a bonfire compared to the object of study but pretty grand, nonetheless, in the human scale of things. The Royal Observatory, where once the Astronomer Royal, an assistant and possibly a gardener or two lived and worked, stands on Edinburgh's Blackford Hill, with stunning terrestrial views of Salisbury Crags and the Firth of Forth beyond. The copper plated domes were erected there over a hundred years ago when the official observation site was moved from Calton Hill, above the city's centre, to outwith the city boundaries in order to escape the urban night glare.

Now when astronomers and astro-physicists want to gaze at the stars they have to go to mountain tops that meet an exacting brief. Not only do they have to be high enough to minimise light pollution and increase the chances of cloudless nights and dry air, they also have to be close to the ocean to benefit from the planet's purest and most smoothly flowing air. Only school parties and guests at the Royal Observatory's Visitor Centre stargaze from Blackford Hill these days, or rather, these nights. For the cutting-edge professors of Edinburgh University's Institute for Astronomy who are based at Blackford Hill, real-time observation requires trips to those faraway mountain tops in places like Hawaii and Chile. But it's no doubt pleasing to know that crucial high-tech components for many of the telescopes they use half way across the world were made in the labs of their neighbours at the UK Astronomy Technology Centre (ATC).

£550 million – now watch this space

The UK Astronomy Technology Centre is the sole UK site funded and administrated by the Particle Physics and Astronomy Research Council (PPARC) and its remit is to keep the UK at the forefront of world astronomy by designing and producing state-of-the-art astronomical technology. PPARC's other two sites are observational sites: the Isaac Newton Group in La Palma and the Joint Astronomy Centre in Hawaii. ATC's current instrumentation projects include the design and manufacture of multi object and mid infrared echelle spectrometers and Submillimetre Common User Bolometer Arrays and its customer-base extends far beyond its sister sites and includes Gemini (in Hawaii and Chile), the European Space Agency and the James Clerk Maxwell Telescope. All these clients operate state of the art land based telescopes. In September 2002 ATC won a £550 million contract from NASA to play a major role in building the successor to the Hubble Space Telescope. The centre will help construct one of three infrared instruments for the Next Generation Space Telescope also known as the James Webb Space Telescope.

Not only is this a prestigious win for Edinburgh, but it also marks the beginning of another exciting chapter for astro-physics as it continues to explore an ever expanding universe in which there are more stars than there are grains of sand on all the beaches of planet Earth. The new telescope will allow astronomers to look even deeper into space as it will have six times the light collecting power of the Hubble Space Telescope and a main mirror – at 20 feet or more – at least three times as wide.

Very old chestnuts

But what do scientists see as they look deeper and deeper into space? Professor James Dunlop of Edinburgh University puts it succinctly: "We see history." Not the history of periwigged and tailcoated luminaries on Calton Hill, but the beginnings of stars and galaxies and the universe itself. To understand the formation of galaxies astro-physicists both wind back the clock to the time before there were any galaxies and observe new galaxies being born. When last at the JCMT in Hawaii Professor Dunlop observed galaxy formation using submillimetre photography which, based on radio wave technology, allows us to see through the shrouding cocoon of dust that optical telescopes cannot penetrate. He's now off to Chile to use the Very Large Telescope at Gemini South to make further optical observations of the submillimetre sources. But he and his contemporaries and his counterparts in space programmes around the world are also grappling with questions like: what is the nature of Dark Matter (the stuff between galaxies that is differently distributed to the matter we know) and, what caused the ripple in the unimaginably hot microwave background, 100,000 years after the Big Bang?

Tomorrow's students of light

For students who want to probe such questions and who want to continue to build the scientific basis on which we might, one day, be able to discover life elsewhere in the universe, Scotland offers an enviable trinity of educational opportunities. Undergraduate and postgraduate courses are offered at St. Andrews and Glasgow Universities as well as Edinburgh. Maybe – who knows – it will be the next generation of astro-physicists that first see through the fog masking the split second after the beginning.