A PASSION FOR SPACE
With The Sky at Night co-presenter Maggie Aderin-Pocock.
Visiting e2v in Chelmsford is like going to see an old friend that I have not seen for many years. The company makes detectors for ground and space-based instrumentation across the world. My dealings with them occurred some 12 years ago, when they supplied two massive charge-coupled devices (CCDs) for the instrument that I was managing.
At the time, the detectors seemed colossal: two chips each 2,048 pixels wide and 4,608 pixels long – and they were quite cutting edge compared to what you would find in your average mobile phone or even a top of the range digital camera. But my detectors paled into insignificance when I met the mock-up to the Gaia array.
The real thing, launched just over a year ago, consists of 106 CCDs each 4,500 by 1,966 pixels, making an array of one billion pixels in total. But what is such a gargantuan array designed to do? Well, like its array the Gaia mission’s goals are vast.
Primarily it is a survey operation, its main objective being to create the largest and most precise 3D map of our Galaxy. It will achieve this by analysing one billion of the Milky Way’s stars, which is about one per cent of its population. Gaia’s instruments will repeatedly scan the sky, observing each of these billion stars an average of 70 times over the five years of the mission’s life. As well as the positions and motions of the stars, Gaia will measure the key physical properties of the celestial bodies in its field of view, building a picture of the brightness, temperature and chemical composition for each.
More than a star mapper
By analysing this data astronomers hope to understand the history and evolution of our Galaxy, looking at star formation, star death and the reuse of heavier elements in these processes. Such a detailed survey is also likely to increase the number of exoplanets we know of: it is expected that Gaia will detect between 10,000 to 50,000 new Jupiter-like planets by measuring the small wobble that these planets create on their local stars.
Due to Gaia’s supersensitivity it will also be able to detect a multitude of faint objects closer to home – minor planets, comets and asteroids – useful for cataloguing near-Earth objects, which are often hard to see and have the potential to be devastating if left undetected.
The data flowing out of the project will not only be immense, but also available to the public. A number of school projects will allow children access to real scientific data to process. And for scientists, the huge amounts of Gaia data coming in over the next few years could prove to transform our understanding of our place in the Universe.
But to my mind, we are just following in the paths of our ancestors. The first recorded star charts and almanacs date back thousands of years. We are merely continuing a long-standing tradition – albeit with accuracies and instruments that would not only have astounded our ancestors, but that even by today’s standards are really quite mind boggling.