Seeing the invisible at the edge of the Universe

Seeing the invisible The Hubble space telescope reveals the two galaxies of the Antennae merging together. The next generation of instruments will enable more detailed study of these galaxies

Dr Helen Walker and Dr Bruce Swinyard, CLRC Rutherford Appleton Laboratory.
Professor Matt Griffin, University of Cardiff.
Dr Dave Clements, Imperial College London.
Dr Alistair Glasse, UK Astronomy Technology Centre.

By changing wavelengths from the visible to the infrared, a new view of the Universe appears: the invisible becomes visible. Tens of thousands of previously undetectable galaxies have come into view through use of infrared-detecting space- and ground- based telescopes. The next generation of instruments will enable scientists to study these galaxies in detail. Scientists will be able to look far back in space and time to the cosmic background radiation generated by the Big Bang, revealing the seeds from which all galaxies grew.

'Light travelling from the most far away galaxies shifts into longer wavelengths the infrared due to the expansion of the Universe', explains Helen Walker of the Council for the Central Laboratory of the Research Councils (CCLRC) Rutherford Appleton Laboratory (RAL). 'As the light travelling from these far away galaxies takes so long to get to earth, what is in fact being seen are the very early stages of development of the Universe. We are in effect looking back in time'.

The first glimpses of young galaxies at large distances were made by the Infrared Astronomical Satellite (IRAS) launched in 1983. By observing infrared emission from enormous bursts of star formation, IRAS has detected about a quarter of a million infrared objects, over half of which are not detected at any other wavelength. 'We believe many of these new objects are galaxies', says Helen, 'but we are waiting for the next generation of instruments to study them with higher resolution and more sensitive detectors'.

The UK is playing a vital role in designing, building, testing and calibrating this next generation of instruments for many different projects. The European Space Agency's (ESA) Herschel satellite